List of neoplasms

• ACTH-producing pituitary gland carcinoma - a rare, hormonally functioning or non-functioning pituitary gland adenocarcinoma that produces corticotropin. It may be associated with cushing disease.
• alk-positive large b-cell lymphoma - a usually aggressive large b-cell lymphoma characterized by the presence of monomorphic immunoblast-like neoplastic b-lymphocytes in a sinusoidal growth pattern. The neoplastic b-lymphocytes express the alk kinase but they lack the 2;5 translocation.
• acanthoma - a benign skin neoplasm composed of epithelial cells.
• accelerated phase chronic myelogenous leukemia, bcr-abl1 positive - a phase of chronic myelogenous leukemia characterized by one or more of the following: 1) myeloblasts accounting for 10-19% of the peripheral blood white cells or of the nucleated cells in the bone marrow, 2) peripheral blood basophils at least 20%, 3) persistent thrombocytopenia that is unrelated to therapy, 4) persistent thrombocytosis despite adequate therapy, 5) increasing white blood cell count and increasing spleen size unresponsive to therapy, and/or evidence of clonal evolution. (who, 2001)
• acidophil stem cell pituitary gland adenoma - an infrequent pituitary gland adenoma composed of cells showing immunoreactivity for prolactin and less often growth hormone. Electron microscopic studies reveal giant mitochondria, a finding not present in any other type of pituitary gland adenomas.
• acinar cell carcinoma - a malignant glandular epithelial neoplasm consisting of secretory cells forming acinar patterns. Representative examples include the acinar cell carcinoma of the pancreas and the acinar adenocarcinoma of the prostate gland.
• acquired hemangioma - a hemangioma that is not present at birth but develops later in life.
• actinic keratosis - a precancerous lesion of the skin composed of atypical keratinocytes. It is characterized by the presence of thick, scaly patches of skin. Several histologic variants have been described, including atrophic, acantholytic, and hyperkeratotic variants.
• acute basophilic leukemia - a rare acute myeloid leukemia in which the immature cells differentiate towards basophils.
• acute bilineal leukemia - an acute leukemia of ambiguous lineage in which there is a dual population of blasts with each population expressing markers of a distinct lineage (myeloid and lymphoid or b-and t-lymphocyte). (who, 2001)
• acute biphenotypic leukemia - an acute leukemia of ambiguous lineage characterized by blasts which coexpress myeloid and t or b lineage antigens or concurrent b and t lineage antigens. (who, 2001)
• acute erythroid leukemia - an acute myeloid leukemia characterized by a predominant immature erythroid population. There are two subtypes recognized: erythroleukemia and pure erythroid leukemia. (who, 2001)
• acute leukemia of ambiguous lineage - an acute leukemia in which the blasts lack sufficient evidence to classify as myeloid or lymphoid or they have morphologic and/or immunophenotypic characteristics of both myeloid and lymphoid cells. (who, 2001)
• acute lymphoblastic leukemia - leukemia with an acute onset, characterized by the presence of lymphoblasts in the bone marrow and the peripheral blood. It includes the acute b lymphoblastic leukemia and acute t lymphoblastic leukemia.
• acute lymphoblastic leukemia by gene expression profile - gene expression-based patient cluster groups in acute lymphoblastic leukemia.
• acute lymphoblastic leukemia by rose cluster - unique gene expression-based patient cluster groups in high-risk b-precursor acute lymphoblastic leukemia determined by recognition of outliers by sampling ends (rose).
• acute megakaryoblastic leukemia - an acute myeloid leukemia in which at least 50% of the blasts are of megakaryocytic lineage. (who, 2001)
• acute monoblastic leukemia - an acute myeloid leukemia in which the monoblasts represent 80% or more of the total cellular population. (who, 2001)
• acute monoblastic and monocytic leukemia - acute myeloid leukemia in which 80% or more of the leukemic cells are of monocytic lineage, including monoblasts, promonocytes, and monocytes. Bleeding disorders are common presenting features.
• acute monocytic leukemia - an acute myeloid leukemia in which the majority of monocytic cells are promonocytes. (who, 2001)
• acute myeloid leukemia - a clonal expansion of myeloid blasts in the bone marrow, blood or other tissues. The classification of acute myeloid leukemias (amls) encompasses four major categories: 1) aml with recurrent genetic abnormalities; 2) aml with multilineage dysplasia; 3) therapy-related aml; 4) aml not otherwise specified. The required bone marrow or peripheral blood blast percentage for the diagnosis of aml is 20% (who classification).
• acute myeloid leukemia (megakaryoblastic) with t(1;22)(p13.3;q13.1); rbm15-mkl1 - an acute myeloid leukemia associated with t(1;22)(p13.3;q13.1) resulting in the expression of rbm15-mkl1 fusion protein. It affects infants and children and usually shows megakaryocytic maturation.
• acute myeloid leukemia arising from previous myelodysplastic syndrome - an acute myeloid leukemia developing in patients with a prior history of myelodysplastic syndrome.
• acute myeloid leukemia not otherwise specified - acute myeloid leukemias that do not fulfill the criteria for inclusion in the group of acute myeloid leukemias which have recurrent genetic abnormalities or myelodysplastic changes, or are therapy-related. This category includes entities classified according to the french-american-british classification scheme.
• acute myeloid leukemia with gene mutations - a term referring to acute myeloid leukemias associated with gene mutations most often of the flt3, npm1, and cebpa genes. These leukemias may have normal karyotypes or additional chromosomal aberrations.
• acute myeloid leukemia with maturation - an acute myeloid leukemia (aml) characterized by blasts with evidence of maturation to more mature neutrophils. (who, 2001)
• acute myeloid leukemia with minimal differentiation - an acute myeloid leukemia (aml) in which the blasts do not show evidence of myeloid differentiation by morphology and conventional cytochemistry. (who, 2001)
• acute myeloid leukemia with multilineage dysplasia - an acute myeloid leukemia arising de novo and not as a result of treatment. It is characterized by the presence of myelodysplastic features in at least 50% of the cells of at least two hematopoietic cell lines. Patients often present with severe cytopenia.
• acute myeloid leukemia with mutated cebpa - an acute myeloid leukemia with non-germline mutations of the cebpa gene.
• acute myeloid leukemia with mutated npm1 - an acute myeloid leukemia with mutation of the nucleophosmin gene. It is usually associated with normal karyotype and frequently has myelomonocytic or monocytic features. It usually responds to induction therapy.
• acute myeloid leukemia with myelodysplasia-related changes - an acute myeloid leukemia with at least 20% blasts in the bone marrow or blood, and either a previous history of myelodysplastic syndrome, multilineage dysplasia or myelodysplastic syndrome-related cytogenetic abnormalities. There is no history of prior cytotoxic therapy for an unrelated disorder, and there is absence of the cytogenetic abnormalities that are present in acute myeloid leukemia with recurrent genetic abnormalities.
• acute myeloid leukemia with recurrent genetic abnormalities - a group of acute myeloid leukemias characterized by recurrent genetic abnormalities, mainly balanced translocations. (who, 2001)
• acute myeloid leukemia with variant mll translocations - a term referring to acute myeloid leukemias with rearrangement of the mll gene which results in translocations with various genes other than the mllt3 (af9) gene.
• acute myeloid leukemia with a variant rara translocation - a term referring to acute myeloid leukemias which show variant translocations involving the rara gene. The variant fusion partners include numa1, zbtb16, stat5b, and npm1. These leukemias often have the morphologic features of acute promyelocytic leukemia.
• acute myeloid leukemia with inv(16)(p13.1q22) or t(16;16)(p13.1;q22); cbfb-myh11 - an acute myeloid leukemia with monocytic and granulocytic differentiation and the presence of a characteristically abnormal eosinophil component in the bone marrow. This type of acute myeloid leukemia has a favorable prognosis. (who, 2001)
• acute myeloid leukemia with inv(16)(p13.1q22); cbfb-myh11 - acute myeloid leukemia characterized by the presence of abnormal bone marrow eosinophils and the characteristic cytogenetic abnormality inv(16)(p13.1q22) which results in the expression of the fusion protein cbfb-myh11.
• acute myeloid leukemia with inv(3) (q21.3;q26.2) or t(3;3) (q21.3;q26.2); gata2, mecom - an acute myeloid leukemia associated with inv(3)(q21.3q26.2) or t(3;3)(q21.3;q26.2) resulting in the reposition of a distal gata2 enhancer to activate mecom expression. It may present de novo or follow a myelodysplastic syndrome. The clinical course is aggressive.
• acute myeloid leukemia with inv(3) (q21.3;q26.2); gata2, mecom - an acute myeloid leukemia associated with inv(3)(q21.3q26.2) resulting in the reposition of a distal gata2 enhancer to activate mecom expression. It may present de novo or follow a myelodysplastic syndrome. The clinical course is aggressive.
• acute myeloid leukemia with t(11;17)(q13;q21) - acute myeloid leukemia with the variant rara t(11;17)(q13;q21) and the expression of numa1-rara fusion protein.
• acute myeloid leukemia with t(11;17)(q23;q21) - acute myeloid leukemia with the variant rara t(11;17)(q23;q21) and the expression of plzf-rara fusion protein. It lacks differentiation response to retinoids treatment.
• acute myeloid leukemia with t(16;16)(p13.1;q22); cbfb-myh11 - acute myeloid leukemia characterized by the presence of abnormal bone marrow eosinophils and the characteristic cytogenetic abnormality t(16;16)(p13.1;q22) which results in the expression of the fusion protein cbfb-myh11.
• acute myeloid leukemia with t(17;17)(q21;q21) - acute myeloid leukemia with the variant rara t(17;17)(q21;q21) and the expression of stat5b-rara fusion protein.
• acute myeloid leukemia with t(3;3) (q21.3;q26.2); gata2, mecom - an acute myeloid leukemia associated with t(3;3)(q21.3;q26.2) resulting in the reposition of a distal gata2 enhancer to activate mecom expression. It may present de novo or follow a myelodysplastic syndrome. The clinical course is aggressive.
• acute myeloid leukemia with t(5;17)(q35;q21) - acute myeloid leukemia with the variant rara t(5;17)(q35;q21) and the expression of npm1-rara fusion protein.
• acute myeloid leukemia with t(6;9) (p23;q34.1); dek-nup214 - an acute myeloid leukemia associated with t(6;9)(p23;q34.1) resulting in dek-nup214(can) fusion protein expression. It is often associated with multilineage dysplasia and basophilia. It affects both children and adults and it usually has an unfavorable clinical outcome.
• acute myeloid leukemia with t(7;12)(q36;p13); hlxb9-etv6 - an acute myeloid leukemia in infancy characterized by t(7;12)(q36;p13) and fusion of the homeobox gene hlxb9 (mnx1) with the etv6 gene.
• acute myeloid leukemia with t(8;21); (q22; q22.1); runx1-runx1t1 - an acute myeloid leukemia with t(8;21)(q22; q22.1) giving rise to runx1/runx1t1 fusion transcript and showing maturation in the neutrophil lineage. The bone marrow and the peripheral blood show large myeloblasts with abundant basophilic cytoplasm, often containing azurophilic granules. This type of aml is associated with good response to chemotherapy and high complete remission rate.
• acute myeloid leukemia with t(9;11)(p21.3;q23.3); mllt3-mll - an acute myeloid leukemia associated with t(9;11)(p21.3;q23.3) and mllt3-mll (kmt2a) fusion protein expression. Morphologically it usually has monocytic features. It may present at any age but it is more commonly seen in children. Patients may present with disseminated intravascular coagulation.
• acute myeloid leukemia without maturation - an acute myeloid leukemia (aml) characterized by blasts without evidence of maturation to more mature neutrophils. (who, 2001)
• acute myelomonocytic leukemia - an acute leukemia characterized by the proliferation of both neutrophil and monocyte precursors. (who, 2001)
• acute myelomonocytic leukemia with abnormal eosinophils - acute myelomonocytic leukemia characterized by the presence of abnormal bone marrow eosinophils. It is associated with inv(16)(p13.1;q22) or t(16;16)(p13.1;q22). It has a favorable prognosis.
• acute myelomonocytic leukemia without abnormal eosinophils - acute myelomonocytic leukemia without an abnormal eosinophilic component in the bone marrow.
• acute panmyelosis with myelofibrosis - an acute myeloid leukemia characterized by bone marrow fibrosis without preexisting primary myelofibrosis.
• acute promyelocytic leukemia with pml-rara - an acute myeloid leukemia (aml) in which abnormal promyelocytes predominate. It is characterized by the pml-rara fusion. There are two variants: the typical and microgranular variant. This aml is particularly sensitive to treatment with all trans-retinoic acid and has a favorable prognosis. (who)
• acute undifferentiated leukemia - a rare acute leukemia of ambiguous lineage in which the blasts do not express markers specific to myeloid or lymphoid lineage.
• adamantinoma - a low grade malignant neoplasm arising from the long bones. The tibia is the most frequently affected bone site. Patients present with swelling which may or may not be associated with pain. Morphologically, it is characterized by a biphasic pattern consisting of an epithelial and an osteofibrous component. The vast majority of cases recur if they are not treated with radical surgery. In a minority of cases the tumor may metastasize to other anatomic sites including lymph nodes, lungs, liver, brain, and skeleton.
• adenocarcinoma - a common cancer characterized by the presence of malignant glandular cells. Morphologically, adenocarcinomas are classified according to the growth pattern (e.G., papillary, alveolar) or according to the secreting product (e.G., mucinous, serous). Representative examples of adenocarcinoma are ductal and lobular breast carcinoma, lung adenocarcinoma, renal cell carcinoma, hepatocellular carcinoma (hepatoma), colon adenocarcinoma, and prostate adenocarcinoma.
• adenocarcinoma in situ - a lesion in which the normally situated glands are partially or completely replaced by atypical cells with malignant characteristics.
• adenoid cystic carcinoma - a malignant tumor arising from the epithelial cells. Microscopically, the neoplastic epithelial cells form cylindrical spatial configurations (cribriform or classic type of adenoid cystic carcinoma), cordlike structures (tubular type of adenoid cystic carcinoma), or solid structures (basaloid variant of adenoid cystic carcinoma). Adenoid cystic carcinomas mostly occur in the salivary glands. Other primary sites of involvement include the lacrimal gland, the larynx, and the lungs. Adenoid cystic carcinomas spread along nerve sheaths, resulting in severe pain, and they tend to recur. Lymph node metastases are unusual; hematogenous tumor spread is characteristic.
• adenoma of the colon with intramucosal adenocarcinoma - an intramucosal malignant glandular epithelial infiltrate in a colonic adenoma. There is no evidence of submucosal invasion.
• adenomatoid tumor - a benign neoplasm arising from mesothelial cells. It is characterized by the formation of glandular and tubular patterns. It can occur in several anatomic sites including the pleura, peritoneum, and epididymis.
• adenomyoma - a benign neoplasm characterized by the presence of a glandular and a mesenchymal (fibromyomatous) component. It occurs in the uterine corpus and the cervix. A variant of adenomyoma associated with glandular architectural complexity is called atypical polypoid adenomyoma. Simple polypectomy is usually curative. Atypical polypoid adenomyoma may recur following polypectomy.
• adenosarcoma - a low grade malignant neoplasm characterized by the presence of a benign epithelial component (tubular and cleft-like glands) and a low grade sarcomatous component that contains varying amounts of fibrous and smooth muscle tissues. In a minority of cases, the sarcomatous component contains heterologous elements including striated muscle, cartilage, and fat. It occurs in the uterine corpus, ovary, fallopian tube, cervix, and vagina. It may recur and in a minority of cases may metastasize to distant anatomic sites.
• adenosquamous carcinoma - an invasive carcinoma composed of malignant glandular cells and malignant squamous cells.
• adnexal carcinoma - a carcinoma arising from the sebaceous glands, sweat glands, or the hair follicles. Representative examples include sebaceous carcinoma, apocrine carcinoma, eccrine carcinoma, and pilomatrical carcinoma.
• adrenal cortex adenoma - a benign neoplasm that can arise from any of the adrenal cortical layers. It can be associated with the overproduction of glucocorticoids (cushing's syndrome), androgenic or estrogenic steroids (adrenogenital syndrome), or mineralocorticoids (conn's syndrome). (sternberg diagnostic surgical pathology, 3rd ed.)
• adrenal cortex carcinoma - a rare, usually large (greater than 5cm), malignant epithelial tumor arising from the adrenal cortical cells. Symptoms are usually related to the excessive production of hormones, and include cushing's syndrome and virilism in women. Common sites of metastasis include liver, lung, bone, and retroperitoneal lymph nodes. Advanced radiologic procedures have enabled the detection of small tumors, resulting in the improvement of the 5-year survival.
• adrenal gland pheochromocytoma - a benign or malignant neuroendocrine neoplasm of the sympathetic nervous system that secretes catecholamines. It arises from the chromaffin cells of the adrenal medulla. Clinical presentation includes headaches, palpitations, chest and abdominal pain, hypertension, fever, and tremor. Microscopically, a characteristic nesting (zellballen) growth pattern is usually seen. Other growth patterns including trabecular pattern may also be present.
• aflatoxins-related hepatocellular carcinoma - a hepatocellular carcinoma that develops following exposure to aflatoxin.
• aggressive nk-cell leukemia - a rare, highly aggressive, epstein-barr virus-associated leukemia, also known as aggressive nk-cell leukemia/lymphoma; it may represent the leukemic counterpart of nasal type extranodal nk/t-cell lymphomas. It affects primarily teenagers and young adults. It is characterized by the systemic proliferation of nk cells in the peripheral blood, bone marrow, liver, and spleen.
• aggressive osteoblastoma - an osteoblastoma characterized by the presence of prominent epithelioid osteoblasts and recurrences.
• aggressive systemic mastocytosis - an aggressive and progressive mast cell neoplasm characterized by systemic infiltration of internal organs by aggregates of neoplastic mast cells. There is no evidence of mast cell leukemia or clonal hematologic malignancy. Clinical symptoms include hepatomegaly, splenomegaly, portal hypertension, malabsorption syndrome, and pathologic fractures.
• alcohol-related hepatocellular carcinoma - a hepatocellular carcinoma that develops following alcohol-induced injury of the liver parenchyma.
• alkylating agent-related acute myeloid leukemia - acute myeloid leukemia occurring as late complication of prior therapy with alkylating agents.
• alkylating agent-related myelodysplastic syndrome - a disorder seen following cancer chemotherapy. It is the most common cause of therapy-related myelodysplastic syndromes. It typically manifests several years after initiation of single or multi-agent chemotherapy with alkylators. Mutagenic potential of alkylating agents is believed to be age and cumulative dose-dependent. Deletions in chromosomes 5 and 7 are associated with susceptibility to this disorder. Clinical signs may include fatigue, dyspnea, bruising and frequent infections. Clinical course may progress to bone marrow failure or acute myeloid leukemia that is refractory to treatment. Prognosis is dismal with survivability usually less than one year.
• alpha heavy chain disease - a clonal disorder, also known as immunoproliferative small intestinal disease or mediterranean lymphoma, characterised by the secretion of a defective alpha heavy chain. It predominantly affects young people in the mediterranean region. It involves the small intestine, and patients usually present with malabsorption syndrome, abdominal pain, weight loss, and fever. There is extensive villous atrophy of the small intestinal mucosa, which is heavily infiltrated by small lymphocytes and plasma cells. The small intestinal morphologic changes are consistent with a mucosa-associated lymphoid tissue lymphoma (malt lymphoma).
• alveolar adenoma - a benign, well circumscribed lung neoplasm morphologically characterized by the presence of cystic spaces resembling alveoli, lined by a simple cuboidal epithelium. The cystic spaces are surrounded by a spindle cell stroma which may show myxoid changes. It is a solitary, usually peripheral lung lesion. Patients are usually asymptomatic and its discovery is an incidental finding during chest x-ray examination. Surgical excision is curative.
• alveolar rhabdomyosarcoma - a rapidly growing malignant mesenchymal neoplasm. It is characterized by the presence of round cells with myoblastic differentiation and a fibrovascular stroma resembling an alveolar growth pattern. The tumor usually presents in the extremities.
• amelanotic melanoma - a melanoma characterized by the complete absence of melanin pigment in the melanoma cells. It occurs more frequently on the face and it is often associated with desmoplastic reaction.
• ampulla of vater adenocarcinoma - an invasive carcinoma with glandular differentiation arising from the ampulla of vater. Signs and symptoms include jaundice, abdominal pain, anorexia, nausea, vomiting, and weight loss.
• ampulla of vater adenoma, intestinal-type - an adenoma that arises from the ampulla of vater and resembles the adenomas of the small and large intestines. Morphologically, according to the growth pattern, it may be classified as tubular, tubulovillous, or villous. Dysplasia is always present. Jaundice may be an early symptom.
• ampulla of vater carcinoma - a carcinoma arising from the ampulla of vater. The vast majority of cases are adenocarcinomas. Signs and symptoms include jaundice, abdominal pain, anorexia, nausea, vomiting, and weight loss.
• anal adenocarcinoma - an adenocarcinoma arising in the anal canal epithelium, including the mucosal surface, the anal glands, and the lining of fistulous tracts. The prognosis is related to the stage at diagnosis.
• anal canal adenocarcinoma - an anal adenocarcinoma arising from the anal canal mucosa. Morphologically, it resembles the adenocarcinoma which arises from the colorectal glandular epithelium. Symptoms include anal pruritus, discomfort when sitting, pain, change in bowel habit, and bleeding.
• anal canal carcinoma - a squamous cell carcinoma or less frequently an adenocarcinoma, often associated with human papillomavirus (hpv) infection. Homosexual men are at particular risk. The most important prognostic factors are tumor stage and nodal status.
• anal canal squamous cell carcinoma - a squamous cell carcinoma arising from the mucosa of the anal canal.
• anal carcinoma - a carcinoma that arises from the anus. Anal carcinomas include the anal canal and perianal area (anal margin) carcinomas. Perianal carcinomas are staged separately as skin carcinomas in ajcc v6 and v7 editions. The ajcc v8 edition staging system applies to all carcinomas arising in the anal canal, including carcinomas that arise within anorectal fistulas and those arising in the perianal area (anal margin).
• anal extramucosal (perianal) adenocarcinoma - an anal adenocarcinoma arising from the lining of an anorectal fistulous tract or the anal glands. The overlying anal mucosa does not show evidence of neoplastic changes. It usually presents as a submucosal tumor.
• anal margin carcinoma - a carcinoma arising in the anal margin or perianal skin (below the anal verge and involving the perianal hair-bearing skin). It includes basal cell and squamous cell carcinoma. Anal margin carcinoma is staged as a skin carcinoma, separately from anal canal carcinoma.
• anal margin squamous cell carcinoma - a squamous cell carcinoma arising from the perianal skin.
• anal paget disease - a slowly spreading, erythematous eczematoid plaque in the anal region. Histologically, the basal part or whole thickness of the squamous epithelium is infiltrated by large cells with abundant pale cytoplasm and large nuclei. Half of the cases are associated with an internal malignancy, most often a colorectal adenocarcinoma. The other half of the cases, have a high local recurrence rate and they may become invasive (who).
• anal squamous cell carcinoma - a squamous cell carcinoma (scc) arising from the anal canal or the anal margin (perianal skin). Human papillomavirus is detected in the majority of cases. Homosexual hiv-positive men have an increased risk of developing anal squamous cell carcinoma in comparison to the general male population. Symptoms include anal pruritus, discomfort when sitting, pain, change in bowel habit, and bleeding. The prognosis is generally better for anal margin scc than for anal canal scc.
• anaplastic (malignant) meningioma - a who grade iii meningioma characterized by the presence of malignant morphologic features, including malignant cytology and a very high mitotic index (20 or more mitoses per ten high power fields).
• anaplastic adrenal cortex carcinoma - an adrenal cortex carcinoma characterized by the presence of necrotic changes, hemorrhage, nuclear atypia, and mitotic activity.
• anaplastic astroblastoma - an astroblastoma characterized by the presence of high mitotic activity, cytologic atypia, and architectural distortion.
• anaplastic astrocytoma - a diffusely infiltrating, who grade iii astrocytoma with focal or dispersed anaplasia, and a marked proliferative potential. It may arise from a low-grade astrocytoma, but it can also be diagnosed at first biopsy, without indication of a less malignant precursor lesion. It has an intrinsic tendency for malignant progression to glioblastoma. (who)
• anaplastic astrocytoma, idh-mutant - anaplastic astrocytoma carrying idh mutations.
• anaplastic astrocytoma, not otherwise specified - anaplastic astrocytoma in which there is insufficient information on the idh genes status.
• anaplastic ependymoma - a who grade iii malignant glioma of ependymal origin with accelerated growth and an unfavorable clinical outcome, particularly in children. It is characterized by high mitotic activity, often accompanied by microvascular proliferation and pseudo-palisading necrosis. (adapted from who)
• anaplastic kidney wilms tumor - wilms tumor of the kidney characterized by the presence of nuclear anaplasia. Anaplasia is defined by the presence of all of the following: multipolar polyploid mitotic figures, marked nuclear enlargement, and hyperchromasia. When anaplasia is diffuse, it is associated with an unfavorable clinical outcome.
• anaplastic large cell lymphoma - a peripheral (mature) t-cell lymphoma, consisting of usually large anaplastic, cd30 positive cells. The majority of cases are positive for the anaplastic large cell lymphoma (alk) protein. The most frequently seen genetic alteration is a t(2;5) translocation. Majority of patients present with advanced disease. The most important prognostic indicator is alk positivity, which has been associated with a favorable prognosis. (who, 2001)
• anaplastic large cell lymphoma, alk-negative - a t-cell peripheral lymphoma morphologically indistinguishable from anaplastic large cell lymphoma, alk-positive. It is characterized by the absence of the translocation involving the alk gene and lacks expression of alk fusion protein.
• anaplastic large cell lymphoma, alk-positive - a t-cell peripheral lymphoma composed of usually large, pleomorphic, cd30 positive t-lymphocytes with abundant cytoplasm characterized by the presence of a translocation involving the alk gene and expression of alk fusion protein. Most patients present with peripheral and/or abdominal lymphadenopathy, and often have advanced disease and extranodal involvement.
• anaplastic lymphoma - a diffuse large b-cell lymphoma variant characterized by the presence of large round, oval, or polygonal cells with bizarre pleomorphic nuclei resembling hodgkin or reed-sternberg cells. It is unrelated to anaplastic large cell lymphoma which is a t-cell non-hodgkin lymphoma.
• anaplastic medulloblastoma - a medulloblastoma characterized by marked nuclear pleomorphism, and high mitotic activity.
• anaplastic oligoastrocytoma - an oligoastrocytoma characterized by the presence of increased cellularity, nuclear atypia, pleomorphism, and high mitotic activity.
• anaplastic oligodendroglioma - a who grade iii oligodendroglioma with focal or diffuse malignant morphologic features (prominent nuclear pleomorphism, mitoses, and increased cellularity).
• anaplastic oligodendroglioma, idh-mutant and 1p/19q-codeleted - an anaplastic oligodendroglioma carrying idh gene family mutation and combined whole-arm losses of 1p and 19q (1p/19q codeletion).
• anaplastic oligodendroglioma, not otherwise specified - an anaplastic oligodendroglioma in which there is insufficient information on the idh genes and 1p/19q codeletion status.
• anaplastic pleomorphic xanthoastrocytoma - a who grade iii pleomorphic xanthoastrocytoma characterized by the presence of five or more mitoses per 10 high-power fields. Necrosis may be present. Patients have shorter survival rates when compared to those with who grade ii pleomorphic xanthoastrocytoma.
• angiofibroma - a morphologic variant of fibroma characterized by the presence of numerous dilated vascular channels.
• angioimmunoblastic t-cell lymphoma - a peripheral t-cell lymphoma of mature t follicular helper (tfh) cells characterized by systemic disease and a polymorphous infiltrate involving lymph nodes, with a prominent proliferation of high endothelial venules and follicular dendritic cells. Ebv-positive cells are nearly always present. It is a clinically aggressive lymphoma and seen mainly in older adults. (who 2017)
• angioleiomyoma - a benign, slow-growing neoplasm that arises from the dermis or subcutaneous tissue. It is characterized by the presence of well-differentiated smooth muscle cells which are arranged around numerous vessels.
• angiomatous meningioma - a who grade I meningioma characterized by the presence of small and medium sized vessels that predominate over the meningioma cells.
• angiosarcoma - a malignant tumor arising from the endothelial cells of the blood vessels. Microscopically, it is characterized by frequently open vascular anastomosing and branching channels. The malignant cells that line the vascular channels are spindle or epithelioid and often display hyperchromatic nuclei. Angiosarcomas most frequently occur in the skin and breast. Patients with long-standing lymphedema are at increased risk of developing angiosarcoma.
• apocrine carcinoma - a carcinoma with apocrine differentiation arising from the sweat glands. It presents as single or multiple nodular lesions which may be ulcerated or hemorrhagic and is usually in the axilla and less often in the anogenital region. It grows in the dermis and infiltrates subcutaneous tissues. It is characterized by the presence of large cells with abundant eosinophilic cytoplasm and large often vesicular nuclei. Most cases are slow growing tumors and have a prolonged course.
• apocrine hidrocystoma - a slow-growing, usually solitary, dome-shaped benign sweat gland adenoma, most frequently located on the eyelid. It is characterized by a cystic proliferation of apocrine glands. Surgical excision is curative.
• appendix adenocarcinoma - a malignant neoplasm arising from the glandular epithelium of the appendix with invasion of the appendiceal wall beyond the muscularis mucosa. The majority of cases are well differentiated adenocarcinomas with mucinous stroma formation. Clinically, it may present as an abdominal mass or with symptoms of acute appendicitis. Patients with chronic ulcerative colitis are at a higher risk in developing appendiceal adenocarcinomas compared to the general population.
• appendix adenoma - a circumscribed neoplasm arising from the glandular epithelium of the appendix. Morphologically, it is characterized by a proliferation of neoplastic glandular cells and it is associated with dysplasia. According to the growth pattern, it may be classified as tubular, villous, or tubulovillous. The dysplasia is classified as mild, moderate, or severe.
• appendix carcinoma - a malignant epithelial neoplasm arising from the appendix. The vast majority of the cases are adenocarcinomas.
• appendix goblet cell adenocarcinoma - an invasive mixed adenoneuroendocrine carcinoma of the appendix characterized by a submucosal growth and the presence of neoplastic signet-ring cells resembling goblet cells of the intestine.
• appendix mucinous adenocarcinoma - an adenocarcinoma arising from the appendix, characterized by the presence of mucinous stroma formation.
• appendix signet ring cell carcinoma - an adenocarcinoma arising from the appendix, characterized by the presence of signet-ring, mucin-producing malignant cells. The signet-ring cells constitute more than fifty-percent of the malignant cells.
• appendix small cell carcinoma - an aggressive, poorly differentiated neuroendocrine malignant neoplasm arising from the wall of the appendix. It is characterized by the presence of small malignant cells, necrotic changes, and an increased mitotic rate.
• asbestos-related malignant mesothelioma - malignant mesothelioma occurring in a patient exposed to asbestos.
• askin tumor - a primitive neuroectodermal tumor (small round blue cell tumor) of the thorax which can involve the periosteum, thoracic wall and/or pleura though it spares the lung parenchyma.
• astroblastoma - a rare glial neoplasm more commonly found in young adults. It is characterized by tumor cells with characteristics suggestive of an astrocytic origin (positive for gfap), arranged perivascularly. The cells have broad, non-tapering processes radiating towards a central blood vessel. The biologic behavior of astroblastomas is variable, so no who grade has been established, yet. (adapted from who.)
• astrocytic tumor - a glial tumor of the brain or spinal cord showing astrocytic differentiation. It includes the following clinicopathological entities: pilocytic astrocytoma, diffuse astrocytoma, anaplastic astrocytoma, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, and glioblastoma.
• astrocytoma - a tumor of the brain or spinal cord showing astrocytic differentiation. It includes the following clinicopathological entities: pilocytic astrocytoma, diffuse astrocytoma, anaplastic astrocytoma, pleomorphic xanthoastrocytoma, and subependymal giant cell astrocytoma.
• atypical burkitt/burkitt-like lymphoma - a morphologic variant of burkitt lymphoma characterized by marked nuclear pleomorphism, abundant apoptotic debris, and the presence of tangible body macrophages.
• atypical carcinoid tumor - a carcinoid tumor characterized by a high mitotic rate, often associated with the presence of necrosis and nuclear pleomorphism.
• atypical chronic myeloid leukemia, bcr-abl1 negative - a myelodysplastic/myeloproliferative neoplasm characterized by the principal involvement of the neutrophil series with leukocytosis and multilineage dysplasia. The neoplastic cells do not have a philadelphia chromosome or the bcr/abl fusion gene. (who, 2001)
• atypical lipomatous tumor - an intermediate, locally aggressive lipomatous neoplasm. Microscopically, the adipose tissue contains large and pleomorphic lipoblasts, and is dissected by fibrous septa containing spindle cells. It requires a wide local excision, may recur locally, but never metastasizes.
• atypical meningioma - a who grade ii meningioma characterized by the presence of brain invasion and an increased mitotic activity, or at least three of the following morphologic features: small cells, high cellularity, prominent nucleoli, lack of architectural pattern, and necrosis.
• atypical teratoid/rhabdoid tumor - an aggressive malignant embryonal neoplasm arising from the central nervous system. It is composed of cells with a large eccentric nucleus, prominent nucleolus, and abundant cytoplasm. Mutations of the ini1 gene or very rarely smarca4 (brg1) gene are present. The vast majority of cases occur in childhood. Symptoms include lethargy, vomiting, cranial nerve palsy, headache, and hemiplegia.
• b acute lymphoblastic leukemia - the most frequent type of acute lymphoblastic leukemia. Approximately 75% of cases occur in children under six years of age. This is a good prognosis leukemia. In the pediatric age group the complete remission rate is approximately 95% and the disease free survival rate is 70%. Approximately 80% of children appear to be cured. In the adult age group the complete remission rate is 60-85%. (who, 2001)
• b acute lymphoblastic leukemia with t(12;21)(p13.2;q22.1); etv6-runx1 - a b-cell acute leukemia characterized by the presence of lymphoblasts that carry a translocation between the tel gene on chromosome 12 and the aml1 gene on chromosome 21, (p13.2;q22.1). It results in the production of the tel-aml1 (etv6-runx1) fusion protein. It is commonly seen in children and rarely in adults. It has a favorable clinical outcome.
• b acute lymphoblastic leukemia with t(1;19)(q23;p13.3); e2a-pbx1 (tcf3-pbx1) - a b-cell acute leukemia characterized by the presence of lymphoblasts that carry a translocation between the e2a gene on chromosome 19 and the pbx1 gene on chromosome 1. It occurs in children and less often in adults.
• b acute lymphoblastic leukemia with t(5;14)(q31.1;q32.3); il3-igh - a rare b-cell acute leukemia characterized by the presence of lymphoblasts that carry a translocation between the il3 gene on chromosome 5 and the igh locus on chromosome 14, (q31.1;q32.3). It results in eosinophilia.
• b acute lymphoblastic leukemia with t(9;22)(q34.1;q11.2); bcr-abl1 - a b-cell acute leukemia characterized by the presence of lymphoblasts that carry a translocation between the bcr gene on chromosome 22 and the abl1 gene on chromosome 9. It results in the production of the p190 kd or p210 kd fusion protein. It has an unfavorable clinical outcome.
• b acute lymphoblastic leukemia with t(v;11q23.3); mll rearranged - a b-cell acute leukemia characterized by the presence of lymphoblasts that carry a translocation between the mll (kmt2a) gene at 11q23.3 and another gene partner resulting in the production of an mll related fusion protein. It is the most commonly seen leukemia in the pediatric population under the age of one year. The prognosis is unfavorable.
• b lymphoblastic leukemia/lymphoma - a neoplasm of lymphoblasts committed to the b-cell lineage, typically composed of small to medium-sized blast cells. When the neoplasm involves predominantly the bone marrow and the peripheral blood, it is called b acute lymphoblastic leukemia. When it involves nodal or extranodal sites, it is called b lymphoblastic lymphoma. (who, 2001)
• b lymphoblastic leukemia/lymphoma with hyperdiploidy - a precursor lymphoid neoplasm composed of b-lymphoblasts which contain more than 50 and usually less than 66 chromosomes. It has a favorable clinical outcome.
• b lymphoblastic leukemia/lymphoma with hypodiploidy - a precursor lymphoid neoplasm composed of b-lymphoblasts which contain less than 46 chromosomes. It has an unfavorable clinical outcome.
• b lymphoblastic leukemia/lymphoma with recurrent genetic abnormalities - the term refers to precursor lymphoid neoplasms which are composed of b-lymphoblasts and characterized by the presence of recurrent genetic abnormalities.
• b lymphoblastic leukemia/lymphoma with t(12;21)(p13.2;q22.1); etv6-runx1 - a precursor lymphoid neoplasm which is composed of b-lymphoblasts and carries a translocation between the tel gene on chromosome 12 and the aml1 gene on chromosome 21, (p13.2;q22.1). It results in the production of the tel-aml1 (etv6-runx1) fusion protein. It has a favorable clinical outcome.
• b lymphoblastic leukemia/lymphoma with t(1;19)(q23;p13.3); e2a-pbx1 (tcf3-pbx1) - a precursor lymphoid neoplasm which is composed of b-lymphoblasts and carries a translocation between the e2a gene on chromosome 19 and the pbx1 gene on chromosome 1.
• b lymphoblastic leukemia/lymphoma with t(5;14)(q31.1;q32.3); il3-igh - a precursor lymphoid neoplasm which is composed of b-lymphoblasts and carries a translocation between the il3 gene on chromosome 5 and the igh locus on chromosome 14, (q31.1;q32.3). It results in eosinophilia.
• b lymphoblastic leukemia/lymphoma with t(9;22)(q34.1;q11.2); bcr-abl1 - a precursor lymphoid neoplasm which is composed of b-lymphoblasts and carries a translocation between the bcr gene on chromosome 22 and the abl1 gene on chromosome 9. It results in the production of the p190 kd or p210 kd fusion protein. It has an unfavorable clinical outcome.
• b lymphoblastic leukemia/lymphoma with t(v;11q23.3); mll rearranged - a precursor lymphoid neoplasm which is composed of b-lymphoblasts and carries a translocation between the mll (kmt2a) gene at 11q23.3 and another gene partner resulting in the production of an mll related fusion protein.
• b lymphoblastic leukemia/lymphoma, not otherwise specified - the term refers to precursor lymphoid neoplasms which are composed of b-lymphoblasts and characterized by the absence of recurrent genetic abnormalities.
• b lymphoblastic lymphoma - an uncommon type of lymphoma. It constitutes approximately 10% of cases of lymphoblastic lymphoma. Approximately 75% of cases reported in a literature review involved patients who were less than 18 years of age. The most commonly affected sites are the skin, bone, soft tissue, and lymph nodes. It has a high remission rate with a median survival of approximately 60 months. (who, 2001)
• b-cell lymphoma, unclassifiable, with features intermediate between diffuse large b-cell lymphoma and classic hodgkin lymphoma - a group of lymphomas displaying molecular, morphologic, immunophenotypic, and clinical overlap between classic hodgkin lymphoma and diffuse large b-cell lymphoma. This term particularly applies to mediastinal lymphomas with overlapping features of mediastinal (thymic) large b-cell lymphoma and classic hodgkin lymphoma.
• b-cell non-hodgkin lymphoma - the most common type of non-hodgkin lymphoma. It includes the most frequently seen morphologic variants which are: diffuse large b-cell lymphoma, follicular lymphoma, small lymphocytic lymphoma and marginal zone b-cell lymphoma.
• b-cell proliferation of uncertain malignant potential - a b-cell lymphoproliferative disorder with uncertain malignant potential. The representative example of this category is lymphomatoid granulomatosis.
• b-cell prolymphocytic leukemia - a malignant b-cell lymphoproliferative process affecting the blood, bone marrow, and spleen. The b-prolymphocytes are medium-sized, round lymphoid cells with prominent nucleoli. The b-prolymphocytes must exceed 55% of lymphoid cells in the blood. Cases of transformed chronic lymphocytic leukemia (cll) and cll with increased prolymphocytes are excluded. The prognosis is poor. (who, 2001)
• balloon cell nevus - an uncommon variant of melanocytic nevus. It presents as a small pigmented skin lesion. It is characterized by the presence of large melanocytes with clear, foamy or finely vacuolated cytoplasm. It may recur if it is not completely excised.
• barrett adenocarcinoma - an adenocarcinoma arising from barrett metaplastic epithelium in the esophagus. There is evidence supporting the idea that the barrett adenocarcinomas develop through a stepwise progression through intestinal metaplastic epithelium to epithelial dysplasia to malignancy. Adenocarcinomas arising in the setting of barrett esophagus are typically papillary and/or tubular. In terms of grading, they are well or moderately differentiated adenocarcinomas.
• bartholin gland carcinoma - a carcinoma that arises from the bartholin gland. It usually affects women over fifty and presents with enlargement of the bartholin gland. Various histologic subtypes have been identified and include adenocarcinoma, squamous cell carcinoma, adenoid cystic carcinoma, adenosquamous carcinoma, transitional cell carcinoma, and small cell carcinoma.
• basal-like breast carcinoma - a biologic subset of breast carcinoma defined by high expression of genes characteristic of basal epithelial cells, including krt5 and krt17, annexin 8, cx3cl1, and trim29, and usually by lack of expression of the estrogen receptor (er), progesterone receptor (pr), and human epidermal growth factor receptor 2 (her2). It is the most common subtype of breast cancer associated with brca1 mutations, and is associated with a poor prognosis.
• basaloid carcinoma - a malignant epithelial neoplasm characterized by the presence of neoplastic cells with hyperchromatic nuclei, small amount of cytoplasm, and peripheral nuclear palisading.
• benign adrenal gland pheochromocytoma - a sporadic or familial pheochromocytoma that is confined to the adrenal gland and does not have any metastatic potential. The majority of cases are sporadic, and usually unilateral. Familial cases are usually bilateral.
• benign breast phyllodes tumor - a usually unilateral, benign and well circumscribed biphasic neoplasm that arises from the breast. It usually affects middle-aged women. It is characterized by the presence of a double layer of epithelial cells that are arranged in clefts, surrounded by a cellular, monomorphic spindle cell mesenchymal component. Mitoses are rare. Necrotic changes may be present in large tumors.
• benign extragonadal germ cell tumor - a non-metastasizing germ cell tumor that arises from an anatomic site other than the testis or ovary.
• benign fibrous histiocytoma - a benign neoplasm composed of fibroblastic spindle cells in a whorled storiform pattern. It is characterized by the presence of foam cells, inflammatory cells, hemosiderin deposition and stromal hemorrhage.
• benign gastrointestinal stromal tumor - a gastrointestinal stromal tumor that is characterized by a maximum diameter equal or less than 5 cm (gastric localization), or equal or less than 2 cm (intestinal localization) and no more than 5 mitotic figures per 50 high power fields.
• benign germ cell tumor - a germ cell tumor without metastatic potential.
• benign glomus tumor - a glomus tumor of small size characterized by the absence of nuclear atypia and mitotic activity.
• benign granular cell tumor - a granular cell tumor that is confined to the site of origin, without metastatic potential.
• benign mixed tumor of the skin - a rare, benign, slow-growing and painless neoplasm of sweat glands. It usually arises in the head and neck. It is characterized by the presence of a mesenchymal chondroid stroma, fibrosis, and epithelial structures.
• benign notochordal cell tumor - an intraosseous benign tumor of notochord origin that arises in the bones of the base of the skull, vertebral bodies, sacrum or coccyx. It contains vacuolated tumor cells without atypia, but lacks myxoid matrix, necrosis, and lobular architecture, which are features that characterize its malignant counterpart, chordoma. Most lesions are incidental findings.
• benign ovarian germ cell tumor - a non-metastasizing germ cell tumor that arises from the ovary. The vast majority of cases are benign dermoid cysts.
• benign phyllodes tumor - a benign, circumscribed fibroepithelial neoplasm arising from the breast and rarely the prostate gland. It is characterized by the presence of epithelial structures which are arranged in clefts and by a hypercellular mesenchymal stroma which is organized in leaf-like structures. There is no evidence of cellular atypia or sarcomatous features.
• benign prostate phyllodes tumor - a rare benign neoplasm that arises from the prostate gland and is characterized by the presence of hyperplastic glands and stroma that contains spindle-shaped cells.
• benign skin melanocytic nevus - a benign, circumscribed proliferation of melanocytes in the skin. Variants include the spitz nevus, halo nevus, blue nevus, and balloon cell nevus.
• bilateral breast carcinoma - carcinoma that affects both breasts in a simultaneous or non-simultaneous manner.
• bilateral retinoblastoma - retinoblastoma involving both eyes. This occurs in the majority of patients with the inherited variant. A minority of patient with bilateral retinoblastoma were found to have involvement of the pineal gland as well.
• bile duct adenocarcinoma - an adenocarcinoma arising from the intrahepatic or extrahepatic bile ducts.
• bile duct adenoma - a benign, well-demarcated polypoid neoplasm arising from the bile duct epithelium. According to the growth pattern, it is classified as tubular, papillary, or tubulopapillary. Adenomas arising from the extrahepatic bile ducts usually produce symptoms related to biliary obstruction.
• bile duct carcinoma - a carcinoma arising from the intrahepatic or extrahepatic bile ducts.
• biphasic mesothelioma - a malignant mesothelioma characterized by the presence of epithelioid and sarcomatoid components, with each component representing at least 10% of the tumor.
• bladder adenocarcinoma - a rare adenocarcinoma arising from metaplastic bladder epithelium. It is frequently associated with long-standing local irritation. The majority of cases originate from the trigone and the posterior wall of the bladder.
• bladder carcinoma - a carcinoma arising from the bladder epithelium. Approximately 90% of the bladder carcinomas are transitional cell carcinomas. The remainder are squamous cell carcinomas, adenocarcinomas and small cell neuroendocrine carcinomas.
• bladder papillary urothelial carcinoma - an invasive or non-invasive papillary transitional cell carcinoma of the urinary bladder. It is classified as low - or high-grade.
• bladder squamous cell carcinoma - a squamous cell carcinoma of the bladder arising from metaplastic epithelium. It represents less than 10% of bladder carcinomas. The exception is the middle east along the nile valley, where it represents the most common form of carcinoma because of the endemic nature of schistosomiasis. Bladder squamous cell carcinoma is often associated with long-standing chronic inflammation of the bladder and usually has a poor prognosis. The diagnosis of squamous cell carcinoma of the bladder should be reserved for those tumors that are predominantly keratin forming.
• bladder urachal urothelial carcinoma - a transitional cell carcinoma of the urinary bladder that arises from the urachal epithelium.
• bladder urothelial carcinoma - the most common morphologic subtype of urinary bladder carcinoma (over 90% of cases). It arises from the transitional epithelium. It most often affects males in their sixth and seventh decades of life. Hematuria is the most common symptom at presentation. Pathologic stage is the strongest predictor of survival.
• blast phase chronic myelogenous leukemia, bcr-abl1 positive - an advanced phase of chronic myelogenous leukemia. It is characterized by: 1. The presence of blasts in the peripheral blood or bone marrow that are at least 20% of the peripheral blood white cells or of the nucleated cells in the bone marrow respectively, or 2. An extramedullary proliferation of blasts, and/or 3. When there are large aggregates and clusters of blasts in the bone marrow biopsy specimen (adapted from who, 2001).
• blastema predominant kidney wilms tumor - wilms tumor of the kidney characterized by the predominance of the blastema component.
• blastic plasmacytoid dendritic cell neoplasm - a clinically aggressive neoplasm derived from the precursors of plasmacytoid dendritic cells (also called professional type I interferon-producing cells or plasmacytoid monocytes), with a high frequency of cutaneous and bone marrow involvement and leukemic dissemination. (who 2017)
• blastoid variant mantle cell lymphoma - an aggressive mantle cell lymphoma characterized by the presence of neoplastic b-lymphocytes resembling lymphoblasts.
• blue nevus - an intradermal nevus characterized by the presence of benign pigmented dendritic spindle-shaped melanocytes. It most frequently occurs in the skin of the distal upper extremities, followed by the lower extremities, scalp, face, and buttocks. It usually presents as a single blue or blue-black papular lesion less than 1cm in diameter. Simple excision is usually curative.
• borderline breast phyllodes tumor - a phyllodes tumor of the breast characterized by the presence of intermediate features and a stroma which usually resembles low grade fibrosarcoma.
• borderline phyllodes tumor - a phyllodes tumor with morphologic characteristics which are intermediate between a benign and a malignant phyllodes tumor. The stromal sarcomatous changes are of low grade and are often reminiscent of low grade fibrosarcomas.
• borrelia burgdoferi-associated cutaneous marginal zone lymphoma of mucosa-associated lymphoid tissue - primary cutaneous marginal zone lymphoma of mucosa-associated lymphoid tissue that arises from chronically stimulated lymphoid tissue in the skin in response to borrelia burgdoferi infection.
• bowenoid papulosis - dysplastic papular lesions presenting on the genitalia of either sex. The lesions are associated with human papillomavirus infection. The majority of cases have a benign clinical course, although, a small number of cases with malignant transformation have been reported.
• brain neoplasm - a benign or malignant neoplasm that arises from or metastasizes to the brain.
• breast acinic cell carcinoma - a breast adenocarcinoma characterized by the presence of serous (acinic cell) differentiation.
• breast adenocarcinoma - the most common histologic type of breast carcinoma. Representative examples include invasive ductal carcinoma not otherwise specified, ductal carcinoma in situ, inflammatory carcinoma, secretory carcinoma, signet ring cell carcinoma, tubular carcinoma, invasive lobular carcinoma, and lobular carcinoma in situ.
• breast adenoid cystic carcinoma - an adenoid cystic carcinoma primarily involving the breast. Three morphologic patterns are seen: cribriform, trabecular, and solid. The prognosis is excellent.
• breast adenoma - a benign, well circumscribed neoplasm that arises from the breast. Representative examples include apocrine adenoma, tubular adenoma, and pleomorphic adenoma.
• breast apocrine adenoma - a rare, benign and well circumscribed neoplasm that arises from the breast. It is characterized by the proliferation of epithelial cells with extensive apocrine metaplasia.
• breast carcinoma - a carcinoma arising from the breast, most commonly the terminal ductal-lobular unit. It is the most common malignant tumor in females. Risk factors include country of birth, family history, menstrual and reproductive history, fibrocystic disease and epithelial hyperplasia, exogenous estrogens, contraceptive agents, and ionizing radiation. The vast majority of breast carcinomas are adenocarcinomas (ductal or lobular). Breast carcinoma spreads by direct invasion, by the lymphatic route, and by the blood vessel route. The most common site of lymph node involvement is the axilla.
• breast carcinoma by gene expression profile - a header term that includes the following breast carcinoma subtypes determined by gene expression profiling: luminal a breast carcinoma, luminal b breast carcinoma, her2 positive breast carcinoma, basal-like breast carcinoma, triple-negative breast carcinoma, and normal breast-like subtype of breast carcinoma.
• breast complex fibroadenoma - a breast fibroadenoma that displays fibrocystic changes including apocrine metaplasia, sclerosing adenosis, and cyst formation.
• breast ductal adenoma - a benign, well circumscribed neoplasm that is located within the lumen of a duct in the breast parenchyma. It is characterized by the presence of glandular structures at the periphery and fibrous tissue at the center of the tumor.
• breast ductal carcinoma - a breast carcinoma arising from the ducts. While ductal carcinomas can arise at other sites, this term is universally used to refer to carcinomas of the breast. Ductal carcinomas account for about two thirds of all breast cancers. Two types of ductal carcinomas have been described: ductal carcinoma in situ (dcis) and invasive ductal carcinoma. The latter often spreads to the axillary lymph nodes and other anatomic sites. The two forms of ductal carcinoma often coexist.
• breast ductal carcinoma in situ - a carcinoma entirely confined to the mammary ducts. It is also known as dcis. There is no evidence of invasion of the basement membrane. Currently, it is classified into three categories: high-grade dcis, intermediate-grade dcis and low-grade dcis. In this classification the dcis grade is defined by a combination of nuclear grade, architectural growth pattern and presence of necrosis. The size of the lesion as well as the grade and the clearance margins play a major role in dictating the most appropriate therapy for dcis.
• breast fibroadenoma - a benign tumor of the breast characterized by the presence of stromal and epithelial elements. It presents as a painless, solitary, slow growing, firm, and mobile mass. It is the most common benign breast lesion. It usually occurs in women of childbearing age. The majority of fibroadenomas do not recur after complete excision. A slightly increased risk of developing cancer within fibroadenomas or in the breast tissue of patients previously treated for fibroadenomas has been reported.
• breast giant fibroadenoma - a breast fibroadenoma characterized by a very large size. This term has also been used as a synonym for juvenile fibroadenoma by some authors. The latter is characterized by epithelial hyperplasia and an increased stromal cellularity.
• breast inflammatory carcinoma - an advanced, invasive breast adenocarcinoma characterized by the presence of distinct changes in the overlying skin. These changes include diffuse erythema, edema, peau d'orange (skin of an orange) appearance, tenderness, induration, warmth, enlargement, and in some cases a palpable mass. The skin changes are the consequence of lymphatic obstruction from the underlying invasive breast adenocarcinoma. Microscopically, the dermal lymphatics show prominent infiltration by malignant cells. The invasive breast adenocarcinoma is usually of ductal, nos type. There is not significant inflammatory cell infiltrate present, despite the name of this carcinoma.
• breast intracanalicular fibroadenoma - a morphologic variant of breast fibroadenoma without clinical significance. It is characterized by distortion and compression of the ducts by proliferating stromal cells.
• breast intraductal papillary carcinoma - a non-invasive breast adenocarcinoma located in a distended duct. It is characterized by the presence of papillary structures with fibrovascular stalks. In the absence of ductal carcinoma in situ or invasive carcinoma in adjacent tissues, the prognosis is usually favorable.
• breast juvenile fibroadenoma - a breast fibroadenoma characterized by epithelial hyperplasia and an increased stromal cellularity.
• breast lobular carcinoma - an adenocarcinoma of the breast arising from the lobules. This is a relatively uncommon carcinoma, represents approximately 10% of the breast adenocarcinomas and is often bilateral or multifocal.
• breast lobular carcinoma in situ - a non-invasive adenocarcinoma of the breast characterized by a proliferation of monomorphic cells completely filling the lumina. The overall lobular architecture is preserved. It is frequently multifocal (90% in some series) and bilateral. It seldom becomes invasive; however there is an increased risk of infiltrating ductal adenocarcinoma.
• breast medullary carcinoma - an infiltrating breast carcinoma with a relatively favorable prognosis. It is an uncommon carcinoma, accounting for less than 1% of all infiltrating breast carcinomas. It is well circumscribed, with soft cut surface and often of considerable size. Microscopically, the predominant growth pattern is syncytial with broad anastomosing bands or sheets of malignant cells. The malignant cells are round with abundant cytoplasm and vesicular nuclei. The sheets of malignant cells are associated with a marked lymphoplasmacytic infiltrate. Glandular or tubular structures are absent.
• breast mixed ductal and lobular carcinoma - a breast carcinoma characterized by the presence of a lobular and a ductal component. The ductal component comprises less than 50 percent of the tumor.
• breast mucinous carcinoma - an invasive adenocarcinoma of the breast characterized by the presence of islands of small and uniform cells, surrounded by large amounts of mucin. Pure mucinous breast carcinomas generally have a favorable prognosis.
• breast paget disease - a malignant neoplasm in which there is infiltration of the skin overlying the breast by neoplastic large cells with abundant pale cytoplasm and large nuclei with prominent nucleoli (paget cells). It is almost always associated with an intraductal or invasive ductal carcinoma of the breast. The clinical features include focal skin reddening, and eczema. Retraction of the nipple may sometimes occur.
• breast papillary carcinoma - a breast carcinoma characterized by the formation of irregular, finger-like projections of fibrous stroma covered with neoplastic epithelial cells.
• breast pericanalicular fibroadenoma - a morphologic variant of breast fibroadenoma without clinical significance. It is characterized by circumferential proliferation of stromal cells around the ducts. This results in the formation of rounded ductal-epithelial structures.
• breast phyllodes tumor - a benign, malignant, or borderline circumscribed biphasic neoplasm that arises from the breast. It usually affects middle-aged women. It is characterized by the presence of a double layer of epithelial cells that are arranged in clefts, surrounded by a spindle cell mesenchymal (stromal) component.
• breast pleomorphic adenoma - a rare, benign and well circumscribed neoplasm that arises from the breast. It is characterized by the proliferation of epithelial and myoepithelial cells surrounded by chondroid stroma.
• breast secretory carcinoma - a rare, low grade invasive adenocarcinoma of the breast characterized by the presence of cells that secrete milk-like material. Morphologically, it usually appears as a circumscribed lesion, composed of cystic spaces, tubular structures, and solid areas.
• breast small cell carcinoma - a small cell carcinoma that arises from the breast. The morphologic and immunohistochemical features are identical to those seen in the small cell carcinoma of the lung.
• breast squamous cell carcinoma - a rare carcinoma that arises from the breast parenchyma and is entirely composed of squamous cells.
• breast tubular adenoma - a benign, well circumscribed neoplasm that arises from the breast. It is composed entirely of tubular structures that contain epithelial and myoepithelial cells.
• breast tubular carcinoma - an invasive adenocarcinoma of the breast with a favorable prognosis. It is composed of tubular structures lined by a single layer of epithelium.
• bronchial mucosa-associated lymphoid tissue lymphoma - an extranodal marginal zone lymphoma that arises from the lung. It is characterized by the neoplastic proliferation of small b-lymphocytes, monocytoid cells and cells with plasma cell differentiation in the marginal zones of reactive lymphoid follicles. The neoplastic cells infiltrate the interfollicular areas and the bronchial epithelium forming lymphoepithelial lesions. The neoplasm is usually discovered as a mass in a chest x-ray in asymptomatic patients. When symptoms occur, they include cough, dyspnea, hemoptysis, and chest pain. If the lung lesions are resectable, surgery can result in prolonged remission.
• bronchogenic carcinoma - a lung carcinoma arising from the bronchial epithelium.
• buccal mucosa squamous cell carcinoma - a squamous cell carcinoma of the oral cavity that arises from the buccal mucosa.
• burkitt leukemia - the leukemic counterpart of burkitt's lymphoma. The characteristic burkitt cells are seen in the bone marrow and the peripheral blood. This is an aggressive leukemia.
• burkitt lymphoma - a highly aggressive lymphoma composed of monomorphic medium-sized b-cells with basophilic cytoplasm and numerous mitotic figures. It is often associated with the presence of epstein-barr virus (ebv) and is commonly seen in aids patients. Three morphologic variants are recognized: classical burkitt lymphoma, burkitt lymphoma with plasmacytoid differentiation, and atypical burkitt/burkitt-like lymphoma. All cases express the myc translocation [t(8;14)]. (who, 2001)
• burkitt lymphoma with plasmacytoid differentiation - burkitt lymphoma characterized by the presence of malignant cells with eccentric basophilic cytoplasm. The nucleoli of these cells are often single and central. This morphologic variant of burkitt lymphoma is more often seen in patients with immunodeficiency.
• capillary hemangioma - a common hemangioma characterized by the presence of capillary-sized vascular channels without prominent epithelioid endothelial cells.
• carcinoid tumor - a slow growing neuroendocrine tumor, composed of uniform, round, or polygonal cells having monotonous, centrally located nuclei and small nucleoli, infrequent mitoses, and no necrosis. The tumor may show a variety of patterns, such as solid, trabecular, and acinar. Electron microscopy shows small secretory granules. Immunohistochemical studies reveal nse, as well as chromogranin immunoreactivity. Malignant histology (cellular pleomorphism, hyperchromatic nuclei, prominent nucleoli, necrosis, and mitoses) can occasionally be seen. Such cases may have an aggressive clinical course. Gastrointestinal tract and lung are common sites of involvement.
• carcinoma - a malignant tumor arising from epithelial cells. Carcinomas that arise from glandular epithelium are called adenocarcinomas, those that arise from squamous epithelium are called squamous cell carcinomas, and those that arise from transitional epithelium are called transitional cell carcinomas. Morphologically, the malignant epithelial cells may display abnormal mitotic figures, anaplasia, and necrosis. Carcinomas are graded by the degree of cellular differentiation as well, moderately, or poorly differentiated. Carcinomas invade the surrounding tissues and tend to metastasize to other anatomic sites. Lung carcinoma, skin carcinoma, breast carcinoma, colon carcinoma, and prostate carcinoma are the most frequently seen carcinomas.
• carcinoma in situ - a malignant epithelial neoplasm which is confined to the epithelial layer without evidence of further tissue invasion.
• carcinoma ex pleomorphic adenoma - a carcinoma arising in a pre-existing pleomorphic adenoma. It most often occurs in the parotid gland and less often in the submandibular gland and minor salivary gland. Patients usually present with a history of a long-standing mass which recently had undergone rapid growth. The prognosis depends on the invasiveness of the malignant component. Patients with non-invasive or minimally invasive tumors usually have a good prognosis following surgical resection. Invasive tumors are usually aggressive and are associated with recurrences and metastases.
• carcinosarcoma - a malignant tumor composed of a mixture of carcinomatous and sarcomatous elements.
• cardiac rhabdomyoma - a well circumscribed benign tumor arising from cardiac muscle. It usually affects children and may be present in the fetus. Depending on tumor location and size, cardiac, respiratory, and hemodynamic parameters may be affected. There is an association between cardiac rhabdomyoma and tuberous sclerosis.
• cavernous hemangioma - a hemangioma characterized by the presence of cavernous vascular spaces.
• cavernous lymphangioma - a lymphangioma characterized by the presence of thin-walled cavernous lymphatic spaces.
• cecum adenocarcinoma - an adenocarcinoma arising from the cecum. It is more frequently seen in populations with a western type diet and in patients with a history of chronic inflammatory bowel disease. Histologic variants include mucinous adenocarcinoma, signet ring cell carcinoma, medullary carcinoma, serrated adenocarcinoma, cribriform comedo-type adenocarcinoma, and micropapillary adenocarcinoma.
• cellular congenital mesoblastic nephroma - a congenital mesoblastic nephroma characterized by increased cellularity, sheet-like proliferation of fibroblastic cells, and increased mitotic activity. Necrotic changes are commonly present.
• cellular ependymoma - an ependymoma which shows conspicuous cellularity without a significant increase in mitotic rate. (adapted from who)
• cellular fibroma - a morphologic variant of fibroma characterized by increased cellularity.
• central nervous system embryonal tumor, not otherwise specified - a term that refers to central nervous system embryonal tumors which are not fully characterized. This category includes tumors previously designated as central nervous system primitive neuroectodermal tumors.
• central nervous system ganglioneuroblastoma - a supratentorial primitive neuroectodermal tumor characterized by the presence of poorly differentiated or undifferentiated neuroepithelial cells and ganglion cells.
• central nervous system hemangioblastoma - a hemangioblastoma arising from structures of the central nervous system.
• central nervous system medulloepithelioma - a rare, usually aggressive malignant embryonal neoplasm of the central nervous system occurring in children. It is characterized by the presence of neuroepithelial cells which form papillary, trabecular, or tubular structures and absence of c19mc amplification. Symptoms include headache, nausea, and vomiting.
• central nervous system neoplasm - a benign or malignant, primary or metastatic neoplasm that affects the brain, meninges, or spinal cord. Representative examples of primary neoplasms include astrocytoma, oligodendroglioma, ependymoma, and meningioma. Representative examples of metastatic neoplasms include carcinoma and leukemia.
• central nervous system neuroblastoma - a neuroblastoma arising from the cerebral hemispheres.
• central nervous system solitary fibrous tumor/hemangiopericytoma - a mesenchymal, non-meningothelial neoplasm arising from the central nervous system. It is characterized by a collagenous and low cellularity spindle cell and/or hemangiopericytomatous histopathological pattern, recurrent intrachromosomal rearrangement on chromosome 12q that results in the fusion of the nab2 and stat6 genes, high recurrence rates, and long-term risk of systemic metastasis.
• central nervous system solitary fibrous tumor/hemangiopericytoma, grade 1 - a solitary fibrous tumor/hemangiopericytoma that arises from the central nervous system. It corresponds most often to the collagenous and low cellularity spindle cell tumor which was diagnosed as central nervous system solitary fibrous tumor in the past.
• central nervous system solitary fibrous tumor/hemangiopericytoma, grade 2 - a solitary fibrous tumor/hemangiopericytoma that arises from the central nervous system. It corresponds to the more cellular, less collagenous tumor with plump cells and staghorn vasculature which was diagnosed as central nervous system hemangiopericytoma in the past.
• central nervous system solitary fibrous tumor/hemangiopericytoma, grade 3 - a solitary fibrous tumor/hemangiopericytoma that arises from the central nervous system. It most often corresponds to the tumor previously diagnosed as anaplastic hemangiopericytoma.
• central neurocytoma - an intraventricular neuronal neoplasm composed of uniform round cells with neuronal differentiation. It is typically located in the lateral ventricles in the region of the foramen of monro. It generally affects young adults and has a favorable prognosis. (adapted from who)
• centroblastic lymphoma - a b-cell non-hodgkin lymphoma composed of large noncleaved cells. This is a subtype of diffuse large b-cell non-hodgkin lymphoma.
• cerebellar hemangioblastoma - a histologically benign tumor, usually cystic with a vascular mural nodule, that is most often found in the cerebellum though it has been reported at other sites within the neuraxis. It is associated with von hippel-lindau disease (vhl gene located on chr 3p25-26).
• cerebellar liponeurocytoma - a rare, who grade ii cerebellar neoplasm which shows consistent neuronal, variable astrocytic and focal lipomatous differentiation. It occurs in adults, has a low proliferative potential and usually has a favorable prognosis. (adapted from who)
• cerebellopontine angle embryonal tumor, not otherwise specified - a central nervous system embryonal tumor, not otherwise specified arising from the cerebellopontine angle of the infratentorial brain.
• cervical adenocarcinoma - an adenocarcinoma arising from the cervical epithelium. It accounts for approximately 15% of invasive cervical carcinomas. Increased numbers of sexual partners and human papillomavirus (hpv) infection are risk factors. Grossly, advanced cervical adenocarcinoma may present as an exophytic mass, an ulcerated lesion, or diffuse cervical enlargement. Microscopically, the majority of cervical adenocarcinomas are of the endocervical (mucinous) type.
• cervical adenocarcinoma in situ - stage 0 includes: (tis, n0, m0). Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. Figo no longer includes stage 0. (ajcc 7th ed.)
• cervical adenosquamous carcinoma - an uncommon carcinoma arising from the cervix. It is composed of malignant glandular epithelial cells and malignant squamous epithelial cells.
• cervical carcinoma - a carcinoma arising from either the exocervical squamous epithelium or the endocervical glandular epithelium. The major histologic types of cervical carcinoma are: squamous carcinoma, adenocarcinoma, adenosquamous carcinoma, adenoid cystic carcinoma and undifferentiated carcinoma.
• cervical microglandular polyp - a benign endocervical polypoid epithelial hyperplasia characterized by the presence of tightly packed glandular structures. It is usually seen in women on oral contraceptive therapy and during pregnancy.
• cervical small cell carcinoma - a small cell carcinoma arising from the cervix.
• cervical squamous cell carcinoma in situ - stage 0 includes: (tis, n0, m0). Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. Figo no longer includes stage 0. (ajcc 7th ed.)
• cervical squamous cell carcinoma, not otherwise specified - a squamous cell carcinoma arising from the cervical epithelium. It usually evolves from a precancerous cervical lesion. Increased numbers of sexual partners and human papillomavirus (hpv) infection are risk factors for cervical squamous cell carcinoma. The following histologic patterns have been described: conventional squamous cell carcinoma, papillary squamous cell carcinoma, transitional cell carcinoma, lymphoepithelioma-like carcinoma, verrucous carcinoma, condylomatous carcinoma and spindle cell carcinoma. Survival is most closely related to the stage of disease at the time of diagnosis.
• chemotherapy-related leukemia - a leukemia arising as a result of the mutagenic effect of chemotherapy agents that are used for the treatment of a malignant tumor.
• chlamydia psittaci-associated ocular adnexal mucosa-associated lymphoid tissue lymphoma - mucosa-associated lymphoid tissue lymphoma that arises from the ocular adnexa and caused by stimulation of lymphoid tissue due to chlamydia psittaci bacterial infection.
• cholangiocarcinoma - a carcinoma that arises from the intrahepatic bile ducts, the hepatic ducts, or the common bile duct distal to the insertion of the cystic duct. The vast majority of tumors are adenocarcinomas.
• chondroblastic osteosarcoma - an osteosarcoma characterised by the presence of atypical cartilage of variable cellularity. It may or may not be associated with the presence of myxoid areas or focal bone formation.
• chondroblastoma - a benign, chondroid-producing, well-circumscribed, lytic neoplasm usually arising from the epiphysis of long bones. It is characterized by the presence of chondroblasts, osteoclast-like giant cells, chondroid formation, calcification, and mitotic activity. In aggressive cases, there is rearrangement of the 8q21 chromosome band. It occurs most frequently in children and young adults and rarely metastasizes.
• chondroid chordoma - a slow-growing malignant bone tumor arising from the remnants of the notochord and occurring in the base of the skull. The tumor is characterized by a lobulated growth pattern, myxoid stroma formation, and the presence of physaliphorous cells and cartilage.
• chondroma - a benign well circumscribed neoplasm of hyaline cartilage arising from bone or soft tissue. It is characterized by the presence of chondrocytes.
• chondrosarcoma - a malignant cartilaginous matrix-producing mesenchymal neoplasm arising from the bone and soft tissue. It usually affects middle-aged to elderly adults. The pelvic bones, ribs, shoulder girdle, and long bones are the most common sites of involvement. Most chondrosarcomas arise de novo, but some may develop in a preexisting benign cartilaginous lesion.
• chordoid meningioma - a who grade ii, usually recurring meningioma characterized by the predominance of tissues that are histologically similar to chordoma.
• chordoma - a malignant bone tumor arising from the remnants of the fetal notochord. Although it can occur at all ages, it is more frequently seen in middle-aged adults. The most frequent sites of involvement are the sacrococcygeal area, spheno-occipital area, and cervico-thoraco-lumbar spine. Microscopically, chordomas are composed of cells that form cords and lobules, separated by mucoid intercellular tissue. Some of the cells are large (physaliphorous) and have vacuolated cytoplasm and prominent vesicular nuclei. Other tumor cells are small with small nuclei without visible nucleoli. Chordomas tend to recur and may metastasize. The most common sites of metastasis are the skin and bone.
• choriocarcinoma - an aggressive malignant tumor arising from trophoblastic cells. The vast majority of cases arise in the uterus and represent gestational choriocarcinomas that derive from placental trophoblastic cells. Approximately half of the cases develop from a complete hydatidiform mole. A minority of cases arise in the testis or the ovaries. There is often marked elevation of human chorionic gonadotropin (hcg) in the blood. Choriocarcinomas disseminate rapidly through the hematogenous route; the lungs are most frequently affected.
• choroid plexus carcinoma - a malignant neoplasm arising from the choroid plexus. It shows anaplastic features and usually invades neighboring brain structures. Cerebrospinal fluid metastases are frequent. (adapted from who)
• chromophobe renal cell carcinoma - a type of carcinoma that comprises a minority of renal cell carcinomas. It is characterized by loss of chromosomes 1 and y. Based on the cytoplasmic characteristics of the neoplastic cells, this type of carcinoma is classified as classic (typical) or eosinophilic. It has a much better prognosis than other renal cell carcinomas.
• chronic eosinophilic leukemia, not otherwise specified - a rare myeloproliferative neoplasm characterized by a clonal proliferation of eosinophilic precursors resulting in persistently increased numbers of eosinophils in the blood, marrow and peripheral tissues. Since acute eosinophilic leukemia is at best exceedingly rare, the term eosinophilic leukemia is normally used as a synonym for chronic eosinophilic leukemia. In cases in which it is impossible to prove clonality and there is no increase in blast cells, the diagnosis of "Idiopathic hypereosinophilic syndrome" is preferred. (who, 2001)
• chronic lymphocytic leukemia - the most common type of chronic lymphoid leukemia. It comprises 90% of chronic lymphoid leukemias in the united states. Morphologically, the neoplastic cells are small, round b-lymphocytes. This type of leukemia is not considered to be curable with available therapy. (who, 2001)
• chronic lymphocytic leukemia with immunoglobulin heavy chain variable-region gene somatic hypermutation - chronic lymphocytic leukemia characterized by the presence of somatic hypermutation within the immunoglobulin heavy chain gene variable region of neoplastic clones. Patients have a better prognosis as compared to those with unmutated immunoglobulin heavy chain gene variable region rearrangements.
• chronic lymphocytic leukemia with plasmacytoid differentiation - a chronic lymphocytic leukemia characterized by the presence of neoplastic lymphocytes with plasmacytoid morphology.
• chronic lymphocytic leukemia with unmutated immunoglobulin heavy chain variable-region gene - chronic lymphocytic leukemia characterized by the absence of somatic hypermutation within the immunoglobulin heavy chain gene variable region of neoplastic clones. Patients have a significantly worse prognosis as compared to those with mutated immunoglobulin heavy chain gene variable region rearrangements.
• chronic lymphocytic leukemia/small lymphocytic lymphoma - an indolent, mature b-cell neoplasm composed of small, round b-lymphocytes. When the bone marrow and peripheral blood are involved, the term chronic lymphocytic leukemia is used. The term small lymphocytic lymphoma is restricted to cases which do not show leukemic involvement of the bone marrow and peripheral blood.
• chronic lymphocytic leukemia/small lymphocytic lymphoma with immunoglobulin heavy chain variable-region gene somatic hypermutation - a recently recognized variant of chronic lymphocytic leukemia/small lymphocytic lymphoma (cll/sll) expressing somatic hypermutations of the immunoglobulin heavy chain (igh) genes. The recognition of this variant alters the belief that cll/sll is always derived from a naive, pregerminal center b-cell. The presence of somatic hypermutations of igh genes occurs in approximately 50% of cll/sll cases and implies a postgerminal center, memory origin. Patients with this variant of cll/sll have a favorable prognosis, with a reported median survival of more than 24 years.
• chronic lymphocytic leukemia/small lymphocytic lymphoma with unmutated immunoglobulin heavy chain variable-region gene - a recently recognized variant of chronic lymphocytic leukemia/small lymphocytic lymphoma (cll/sll) that lacks somatic hypermutations of the immunoglobulin heavy chain (igh) genes, implying pregerminal center b-cell origin. Microarray gene expression profiling studies have demonstrated the expression of zap-70 gene (syk family tyrosine kinase) in this subset of cll/cll. Patients with this variant of cll/sll have an unfavorable prognosis compared to those with somatic hypermutations of the igh genes, with a median survival of approximately 6-8 years.
• chronic myelogenous leukemia, bcr-abl1 positive - a chronic myeloproliferative neoplasm characterized by the expression of the bcr-abl1 fusion gene. It presents with neutrophilic leukocytosis. It can appear at any age, but it mostly affects middle aged and older individuals. Patients usually present with fatigue, weight loss, anemia, night sweats, and splenomegaly. If untreated, it follows a biphasic or triphasic natural course; an initial indolent chronic phase which is followed by an accelerated phase, a blast phase, or both. Allogeneic stem cell transplantation and tyrosine kinase inhibitors delay disease progression and prolong overall survival.
• chronic myelomonocytic leukemia - a myelodysplastic/myeloproliferative neoplasm which is characterized by persistent monocytosis, absence of a philadelphia chromosome and bcr/abl fusion gene, fewer than 20 percent blasts in the bone marrow and blood, myelodysplasia, and absence of pdgfra or pdgfrb rearrangement.
• chronic myelomonocytic leukemia with eosinophilia - a chronic myelomonocytic leukemia characterized by a peripheral blood eosinophil count of equal or greater than 1.5x10e9/l, and absence of pdgfra or pdgfrb gene abnormalities.
• chronic myelomonocytic leukemia-1 - a chronic myelomonocytic leukemia characterized by the presence of less than 10 percent blasts in the bone marrow and less than 5 percent blasts in the peripheral blood.
• chronic myelomonocytic leukemia-2 - a chronic myelomonocytic leukemia characterized by the presence of 10-19 percent blasts in the bone marrow and 5-19 percent blasts in the peripheral blood or by the presence of auer rods regardless of the blasts count.
• chronic neutrophilic leukemia - a rare chronic myeloproliferative neoplasm characterized by neutrophilic leukocytosis. There is no detectable philadelphia chromosome or bcr/abl fusion gene.
• chronic phase chronic myelogenous leukemia, bcr-abl1 positive - a phase of chronic myelogenous leukemia in which the peripheral blood smear shows leukocytosis due mainly to neutrophils in different stages of maturation. Blasts usually account for less than 2% of the white blood cells counts. The platelet count is normal or increased. Thrombocytopenia is very uncommon during the chronic phase. Most patients have mild anemia. The bone marrow biopsy is hypercellular due to increased numbers of neutrophils and their precursors. Blasts usually account for fewer than 5% of the marrow cells, and more than 10% indicates transformation to the accelerated phase. Megakaryocytes are smaller than normal and have hypolobated nuclei. The spleen is enlarged due to infiltration of the cords of the red pulp by granulocytes. Most patients with chronic myelogenous leukemia are diagnosed in the chronic phase, which usually has an insidious onset and may last from several months to several years. (who, 2001)
• ciliary body benign medulloepithelioma - a rare, unilateral, benign embryonal neoplasm typically presenting as a ciliary body mass during childhood. It arises from primitive medullary epithelium.
• classic congenital mesoblastic nephroma - a congenital mesoblastic nephroma characterized by the presence of interlacing fascicles of fibroblastic cells, low mitotic activity, and collagen formation.
• classic hodgkin lymphoma - a monoclonal b-cell lymphoproliferation in the vast majority of cases. It is characterized by a bimodal age distribution (15-30 years of life and late life). Epstein-barr virus has been postulated to play a role in the pathogenesis of classic hodgkin lymphoma. Morphologically, it is characterized by the presence of reed-sternberg cells and mononuclear hodgkin cells. The reed-sternberg and mononuclear hodgkin cells are cd30 positive in nearly all cases and cd15 positive in the majority of cases. Four histologic subtypes have been distinguished: lymphocyte-rich, nodular sclerosis, mixed cellularity, and lymphocyte-depleted classic hodgkin lymphoma.
• classic medulloblastoma - a medulloblastoma composed of malignant cells with hyperchromatic nucleus and scanty cytoplasm. Homer wright rosettes may be present.
• classical burkitt lymphoma - a burkitt lymphoma characterized by the presence of a uniform malignant lymphocytic infiltrate that is composed of medium-sized cells with round nuclei and multiple basophilic nucleoli, abundant mitotic figures, and a starry-sky pattern due to the presence of multiple tangible body macrophages.
• classical glioblastoma - a molecular subtype of glioblastoma characterized by lack of p53 mutations, chromosome 7 amplifications or deletions, and high levels of egfr amplification.
• clear cell adenocarcinoma - a malignant neoplasm composed of glandular epithelial clear cells. Various architectural patterns may be seen, including papillary, tubulocystic, and solid.
• clear cell chondrosarcoma - a rare, usually low grade chondrosarcoma characterized by the presence of tumor cells with clear cytoplasm. It usually arises in the epiphyseal ends of long bones.
• clear cell ependymoma - an ependymoma, often supratentorial in location, characterized by the presence of ependymal cells with a perinuclear halo.
• clear cell meningioma - a who grade ii morphologic variant of meningioma characterized by the presence of clear glycogen-rich polygonal cells.
• clear cell renal cell carcinoma - a malignant epithelial neoplasm of the kidney characterized by the presence of lipid-containing clear cells within a vascular network. The tumor may metastasize to unusual sites and late metastasis is common.
• clitoral carcinoma - a carcinoma that arises from the clitoris.
• collecting duct carcinoma - also known as collecting duct carcinoma, this is a rare type of renal carcinoma. It arises from the collecting ducts of the renal medulla, and most authors suggest that this is an aggressive tumor.
• colon adenocarcinoma - an adenocarcinoma arising from the colon. It is more frequently seen in populations with a western type diet and in patients with a history of chronic inflammatory bowel disease. Signs and symptoms include intestinal bleeding, anemia, and change in bowel habits. According to the degree of cellular differentiation, colonic adenocarcinomas are divided into well, moderately, and poorly differentiated. Histologic variants include mucinous adenocarcinoma, signet ring cell carcinoma, medullary carcinoma, serrated adenocarcinoma, cribriform comedo-type adenocarcinoma, and micropapillary adenocarcinoma.
• colon adenoma - an adenoma that arises from the colon. The group of colonic adenomas includes tubular, villous, and tubulovillous adenomas, traditional serrated adenomas, sessile serrated adenomas/polyps, and familial adenomatous polyposis.
• colon adenoma with severe dysplasia - an adenoma that arises from the colon. It is characterized by the presence of severe epithelial dysplasia.
• colon adenomatous polyp - a polypoid adenoma that arises from and protrudes into the lumen of the colon. Epithelial dysplasia is always present. According to the architectural pattern it is classified as tubular, tubulovillous, or villous.
• colon adenosquamous carcinoma - an unusual colon carcinoma characterized by the presence of glandular and squamous carcinomatous components. The two carcinomatous components may be admixed within the tumor, or the two may appear separately in different areas.
• colon carcinoma - a malignant epithelial neoplasm that arises from the colon and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas.
• colon intramucosal adenocarcinoma - an adenocarcinoma that arises from the colonic glandular epithelium and invades the lamina propria or muscularis mucosa but not the submucosa.
• colon medullary carcinoma - a rare, invasive colon adenocarcinoma characterized by the presence of sheets of malignant epithelial cells with vesicular nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm. It usually has a favorable prognosis.
• colon mucinous adenocarcinoma - an invasive adenocarcinoma of the colon characterized by the presence of pools of extracellular mucin. Malignant glandular epithelial cells are present in the mucin collections. Mucin constitutes more than 50% of the lesion.
• colon serrated adenocarcinoma - a rare, invasive colon adenocarcinoma characterized by the presence of a malignant infiltrate with serrated glandular architecture.
• colon serrated lesions and polyps - polyps that arises from the colon. They are characterized by the presence of serrated glands and the absence of generalized dysplasia.
• colon signet ring cell adenocarcinoma - an invasive adenocarcinoma of the colon characterized by the presence of malignant glandular epithelial cells which contain prominent intracytoplasmic mucin (signet ring cells). The signet ring cells constitute more than 50% of the malignant cells.
• colon small cell carcinoma - an aggressive, high-grade, and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the colon. It is characterized by the presence of malignant small cells.
• colon squamous cell carcinoma - a very rare colon carcinoma characterized by the presence of a malignant squamous cell infiltrate.
• colon traditional serrated adenoma - an adenoma that arises from the colon. It is characterized by prominent serration of the glands.
• colon tubular adenoma - a usually polypoid neoplasm that arises from the glandular epithelium of the colonic mucosa. It is characterized by a tubular architectural pattern. The neoplastic glandular cells have dysplastic features.
• colon tubulovillous adenoma - a neoplasm that arises from the glandular epithelium of the colonic mucosa. It is characterized by tubular and villous architectural patterns. The neoplastic glandular cells have dysplastic features.
• colon undifferentiated carcinoma - an invasive malignant epithelial tumor that arises from the colon. There is no morphologic, immunophenotypic, or molecular biological evidence of glandular or squamous differentiation.
• colon villous adenoma - a neoplasm that arises from the glandular epithelium of the colonic mucosa. It is characterized by a villous architectural pattern. The neoplastic glandular cells have dysplastic features.
• colorectal adenocarcinoma - the most common type of colorectal carcinoma. It is characterized by the presence of malignant glandular epithelial cells invading through the muscularis mucosa into the submucosa. Histologic variants include mucinous adenocarcinoma, signet ring cell carcinoma, medullary carcinoma, serrated adenocarcinoma, cribriform comedo-type adenocarcinoma, and micropapillary adenocarcinoma.
• colorectal adenoma - an adenoma that arises from the colon or rectum. The group of colorectal adenomas includes tubular, villous, and tubulovillous adenomas, traditional serrated adenomas, sessile serrated adenomas/polyps, and familial adenomatous polyposis.
• colorectal adenoma with mild dysplasia - an adenoma that arises from the colon or rectum. It is characterized by the presence of mild epithelial dysplasia.
• colorectal adenoma with moderate dysplasia - an adenoma that arises from the colon or rectum. It is characterized by the presence of moderate epithelial dysplasia.
• colorectal adenoma with severe dysplasia - an adenoma that arises from the colon or rectum. It is characterized by the presence of severe epithelial dysplasia.
• colorectal adenosquamous carcinoma - an unusual colorectal carcinoma characterized by the presence of glandular and squamous carcinomatous components. The two carcinomatous components may be admixed within the tumor, or the two may appear separately in different areas.
• colorectal carcinoma - a malignant epithelial neoplasm that arises from the colon or rectum and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas.
• colorectal medullary carcinoma - a rare, invasive colorectal adenocarcinoma characterized by the presence of sheets of malignant epithelial cells with vesicular nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm. It usually has a favorable prognosis.
• colorectal mucinous adenocarcinoma - an invasive colorectal adenocarcinoma characterized by the presence of extracellular mucin pools that contain malignant glandular epithelial structures. The extracellular mucin pools occupy more than 50% of the malignant lesion.
• colorectal serrated adenocarcinoma - a rare, invasive colorectal adenocarcinoma characterized by the presence of a malignant infiltrate with serrated glandular architecture.
• colorectal serrated lesions and polyps - polyps that arises from the colon or rectum. They are characterized by the presence of serrated glands and the absence of generalized dysplasia.
• colorectal signet ring cell carcinoma - an invasive colorectal adenocarcinoma characterized by the presence of malignant glandular epithelial cells with prominent intracytoplasmic mucin resulting in the displacement of the nuclei. The malignant glandular cells with intracytoplasmic mucin constitute more than 50% of the malignant cellular infiltrate.
• colorectal small cell carcinoma - an aggressive, high-grade, and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the colon or rectum. It is characterized by the presence of malignant small cells.
• colorectal squamous cell carcinoma - a very rare colorectal carcinoma characterized by the presence of a malignant squamous cell infiltrate.
• colorectal traditional serrated adenoma - an adenoma that arises from the colon or rectum. It is characterized by prominent serration of the glands.
• colorectal tubular adenoma - a usually polypoid neoplasm that arises from the glandular epithelium of the colonic and rectal mucosa. It is characterized by a tubular architectural pattern. The neoplastic glandular cells have dysplastic features.
• colorectal tubulovillous adenoma - a neoplasm that arises from the glandular epithelium of the colonic and rectal mucosa. It is characterized by tubular and villous architectural patterns. The neoplastic glandular cells have dysplastic features.
• colorectal undifferentiated carcinoma - an invasive malignant epithelial tumor that arises from the colon or rectum. There is no morphologic, immunophenotypic, or molecular biological evidence of glandular or squamous differentiation.
• colorectal villous adenoma - a neoplasm that arises from the glandular epithelium of the colonic and rectal mucosa. It is characterized by a villous architectural pattern. The neoplastic glandular cells have dysplastic features.
• combined hepatocellular carcinoma and cholangiocarcinoma - a rare tumor containing unequivocal elements of both hepatocellular and cholangiocarcinoma that are intimately admixed. This tumor should be distinguished from separate hepatocellular carcinoma and cholangiocarcinoma arising in the same liver. The prognosis of this tumor is poor.
• composite hemangioendothelioma - an intermediate, locally aggressive and rarely metastasizing blood vessel neoplasm. It is characterized by the presence of spindle, plump, and epithelioid endothelial cells and cellular atypia.
• composite lymphoma - coexistence of hodgkin and non-hodgkin lymphoma in the same anatomic site.
• compound nevus - a nevus composed of neoplastic melanocytes that infiltrate both the epidermis and the dermis.
• congenital mesoblastic nephroma - a low grade childhood congenital malignant neoplasm arising from the kidney. It is characterized by the presence of fibroblastic cells. The majority of cases occur in the first year of life. Complete excision is usually associated with an excellent prognosis.
• congenital non-progressive hemangioma - a hemangioma present at birth.
• conjunctival squamous cell carcinoma - a low-grade squamous cell carcinoma that arises from the conjunctiva. It is the most common primary malignant tumor that arises from the conjunctiva. It usually affects older white males. Excessive exposure to sunlight is a risk factor. Patients may present with a mass, red eye, or pain.
• conventional leiomyosarcoma - an uncommon, aggressive malignant smooth muscle neoplasm. It is characterized by the presence of atypical large spindle or round cells, nuclear palisading, tumor cell necrosis, mitotic figures and may be associated with vascular invasion.
• conventional osteosarcoma - a high grade malignant bone-forming mesenchymal neoplasm producing osteoid. The tumor arises from the medullary portion of the bone. It affects the long bones and most commonly, the distal femur, proximal tibia, and proximal humerus. Pain with or without a palpable mass is the most common clinical presentation. It usually has an aggressive growth and may metastasize through the hematogenous route. The lung is the most frequent site of metastasis.
• core binding factor acute myeloid leukemia - acute myeloid leukemia characterized by the presence of t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22). These cytogenetic abnormalities result in disruption of the transcription factor cbf, which is a regulator of normal hematopoiesis.
• corneal squamous cell carcinoma - a rare squamous cell carcinoma that arises from the cornea.
• corticotroph adenoma - an adenoma of the pituitary gland that produces corticotropin. The vast majority of cases are associated with cushing disease. Clinical manifestations include truncal obesity with thin extremities, thinning of the skin, osteoporosis, and a tendency to bruise easily. Silent or hormonally non-functioning acth producing adenomas have also been described. They produce symptoms of a mass-related lesion.
• cribriform neuroepithelial tumor - a very rare, nonrhabdoid, intraventricular tumor with relatively favorable prognosis. It is characterized by the presence of neuroepithelial cells forming cribriform patterns, trabeculae, epithelial membrane antigen immunopositivity on epithelial surfaces, and loss of nuclear ini 1 expression.
• cutaneous melanoma - a primary melanoma arising from atypical melanocytes in the skin. Precursor lesions include acquired and congenital melanocytic nevi, and dysplastic nevi. Several histologic variants have been recognized, including superficial spreading melanoma, acral lentiginous melanoma, nodular melanoma, and lentigo maligna melanoma.
• cutaneous nodular melanoma - an aggressive form of melanoma, frequently metastasizing to the lymph nodes. It presents as a papular or nodular raised skin lesion. It comprises approximately 10-15% of melanomas. Morphologically, it often displays an epithelioid appearance.
• cylindroma - a benign sweat gland neoplasm usually occurring in the scalp or the face. It may present as solitary or multiple papular or nodular lesions. It may be a sporadic lesion or part of brooke-spiegler syndrome. It arises from the dermis and has a multinodular, circumscribed appearance. The nodules contain basaloid cells with small, dark nuclei. Complete excision is usually curative.
• cystadenocarcinoma - a malignant cystic epithelial neoplasm arising from the glandular epithelium. The malignant epithelial cells invade the stroma. The cystic spaces contain serous or mucinous fluid. Representative examples include ovarian and pancreatic cystadenocarcinomas.
• cytogenetically normal acute myeloid leukemia - acute myeloid leukemia not associated with cytogenetic abnormalities.
• ddit4l acute lymphoblastic leukemia - a gene expression subtype of acute lymphoblastic leukemia characterized by its expression level of the ddit4l gene.
• dedifferentiated chondrosarcoma - an aggressive morphologic variant of chondrosarcoma. It is composed of a low grade chondrosarcoma and a high grade non-cartilagenous sarcomatous component. Due to the aggressive nature of the disease, its prognosis is poor.
• dedifferentiated chordoma - a high-grade malignant bone tumor arising from the remnants of the notochord. It is characterized by a lobulated growth pattern, myxoid stroma formation, the presence of physaliphorous cells, and a sarcomatous component.
• dedifferentiated liposarcoma - an atypical lipomatous tumor/well differentiated liposarcoma that shows progression to a usually non-lipomatous, high grade sarcoma. The non-lipomatous sarcoma component may be present in the primary lesion or at the site of recurrence.
• deep benign fibrous histiocytoma - a rare, well-circumscribed, pseudo-encapsulated benign fibrous histiocytoma that arises entirely within the subcutaneous tissue or deep soft tissue. It usually affects the extremities or the head and neck region. It recurs locally in a minority of cases.
• deep hemangioma - a hemangioma arising from the deep soft tissues.
• dermal fibroma - a benign neoplasm arising from the dermis. It is characterized by the presence of spindle-shaped fibroblasts.
• dermal nevus - a nevus characterized by the proliferation of nevus cells in the dermis without involvement of the dermal-epidermal junction.
• dermatofibrosarcoma protuberans - a low grade fibroblastic neoplasm presenting as a nodular cutaneous mass, most often on the trunk and the proximal extremities. The tumor diffusely infiltrates the dermis and the subcutaneous tissues. It is considered a locally aggressive neoplasm, which often recurs but rarely metastasizes.
• desmoid-type fibromatosis - an insidious, locally aggressive, poorly circumscribed neoplasm arising from the deep soft tissues. It is characterized by the presence of elongated spindle-shaped fibroblasts, collagenous stroma formation, and an infiltrative growth pattern. It lacks metastatic potential.
• desmoplastic infantile astrocytoma - a who grade I large cystic tumor that occurs almost exclusively in infants, with a prominent desmoplastic stroma having a neuroepithelial population consisting mainly of neoplastic astrocytes. It involves the superficial cerebral cortex and leptomeninges, and often attaches to the dura. Although clinically it presents as large tumor, it generally has a good prognosis following surgical resection. (adapted from who)
• desmoplastic infantile ganglioglioma - a who grade I large cystic tumor that occurs almost exclusively in infants, with a prominent desmoplastic stroma having a neuroepithelial population of neoplastic astrocytes together with a variable neuronal component. It involves the superficial cerebral cortex and leptomeninges, and often attaches to the dura. Although clinically it presents as a large tumor, it generally has a good prognosis following surgical resection. (adapted from who)
• desmoplastic mesothelioma - a malignant neoplasm arising from mesothelial cells. It is characterized by the presence of a dense collagenous tissue and atypical neoplastic cells. Sarcomatoid features, collagenous necrosis, and infiltration of muscle and adipose tissue may be present. It occurs in the pleura and less commonly in the peritoneum.
• desmoplastic nevus - a benign melanocytic nevus characterized by the presence of desmoplastic stroma.
• desmoplastic/nodular medulloblastoma - a medulloblastoma characterized by the presence of nodular, collagenous areas which do not contain reticulin, surrounded by hypercellular areas which contain an intercellular reticulin fiber network.
• differentiated retinoblastoma - a retinoblastoma with well differentiated features. It often produces flexner-wintersteiner rosettes or homer-wright rosettes. In some cases the tumor cells form fleurettes.
• differentiating neuroblastoma - a neuroblastoma in which the differentiating neuroblasts constitute more than five-percent of the tumor cells.
• diffuse astrocytoma - a low-grade (who grade ii) astrocytic neoplasm. It is characterized by diffuse infiltration of neighboring central nervous system structures. These lesions typically affect young adults and have a tendency for progression to anaplastic astrocytoma and glioblastoma. Based on the idh genes mutation status, diffuse astrocytomas are classified as idh-mutant, idh-wildtype, and not otherwise specified.
• diffuse astrocytoma, idh-mutant - diffuse astrocytoma carrying idh mutations.
• diffuse astrocytoma, not otherwise specified - diffuse astrocytoma in which there is insufficient information on the idh genes status.
• diffuse blastoid b-cell lymphoma - a distinct subtype of high-grade follicular center cell lymphoma, representing a diffuse transformation of conventional follicular lymphoma. Although this type of lymphoma strongly expresses bcl-2, it does not carry the characteristic t(14;18)(q32;q21) chromosomal translocation found in follicular lymphomas. Instead, extra copies of chromosome 18 are often detected.
• diffuse follicular lymphoma - a lymphoma with the morphologic and immunophenotypic features of a follicular lymphoma that shows entirely a diffuse pattern. It is usually seen in small biopsy specimens and most probably represents a diffuse area of a follicular lymphoma.
• diffuse glioma - a glioma that has diffusely infiltrated the surrounding central nervous system tissues.
• diffuse large b-cell lymphoma - a non-hodgkin lymphoma characterized by a diffuse proliferation of predominantly large neoplastic b lymphocytes. It is the most frequently seen type of non-hodgkin lymphoma, representing 30%-40% of the cases. Morphologic variants include centroblastic lymphoma, immunoblastic lymphoma, and anaplastic lymphoma. Subtypes/entities include t-cell/histiocyte rich large b-cell lymphoma, primary diffuse large b-cell lymphoma of the central nervous system, plasmablastic lymphoma, primary cutaneous diffuse large b-cell lymphoma, leg type, and alk-positive large b-cell lymphoma.
• diffuse large b-cell lymphoma activated b-cell type - a biologic subset of diffuse large b-cell lymphomas with a unique molecular signature or expression profile. It represents approximately 30% of diffuse large b-cell lymphomas, and is characterized by the expression of cd44, pkcbeta1, cyclin d2, bcl-2, and irf4/mum1 genes. Morphologically, these lymphomas are either centroblastic or immunoblastic (ratio 2:1). Patients with this type of diffuse large b-cell lymphoma are reported to have a less favorable outcome compared to those with a germinal center b-cell expression profile, with a 5-year survival rate of 35% and a median survival of 2 years.
• diffuse large b-cell lymphoma associated with chronic inflammation - a diffuse large b-cell lymphoma arising in body cavities or narrow spaces of long standing chronic inflammation. The classic example is the pyothorax-associated lymphoma that arises in the pleural cavity of patients with a history of long standing pyothorax.
• diffuse large b-cell lymphoma germinal center b-cell type - a biologic subset of diffuse large b-cell lymphomas with a unique molecular signature or expression profile. It represents approximately 50% of diffuse large b-cell lymphomas, and is characterized by the expression of cd10, bcl-6, a-myb, and lmo2 genes, bcl-2 translocation, and c-rel amplification. Morphologically, the vast majority of these lymphomas are centroblastic and a small minority are immunoblastic (ratio20:1). Patients with this type of diffuse large b-cell lymphoma have a more favorable outcome, with a 5-year survival rate of 60% and a median survival of 10 years.
• diffuse large b-cell lymphoma unclassifiable - a biologic subset of diffuse large b-cell lymphomas (dlbcl) that do not overexpress the genes whose overexpression characterizes the germinal center b-cell-like and activated b-cell-like dlbcl. Morphologically, these lymphomas are either immunoblastic or centroblastic. Patients with this type of diffuse large b-cell lymphoma are reported to have a less favorable outcome, similar to those with an activated b-cell-like gene expression profile.
• diffuse large b-cell lymphoma, not otherwise specified - a term referring to a group of diffuse large b-cell lymphomas which are biologically heterogeneous. These lymphomas have a centroblastic, immunoblastic, or anaplastic morphology.
• diffuse large b-cell lymphoma, not otherwise specified by gene expression profile - a header term that includes the following diffuse large b-cell lymphoma subtypes by gene expression profiling: activated b-cell-like diffuse large b-cell lymphoma, germinal center b-cell-like diffuse large b-cell lymphoma, and type 3 diffuse large b-cell lymphoma.
• diffuse malignant mesothelioma - a malignant neoplasm that arises from the mesothelial cells. Histologic variants include biphasic, epithelioid, sarcomatoid, and desmoplastic mesothelioma.
• diffuse retinoblastoma - a retinoblastoma characterized by the absence of a distinct retinal mass and the presence of malignant cells diffusely infiltrating the retina. It is often confused with uveitis and endophthalmitis, resulting in delayed diagnosis of the malignancy.
• digestive system adenoma - a sporadic or less frequently familial neoplasm, arising from the glandular epithelium of the stomach, small intestine, biliary tract, colon, and rectum. It is a polypoid or flat circumscribed lesion. Morphologically, it is characterized by a proliferation of neoplastic glandular cells and it is associated with dysplasia. According to the growth pattern, it may be classified as tubular, villous, or tubulovillous. The dysplasia is classified as mild, moderate, or severe. The frequency of malignant transformation depends on the size of the lesion and the degree of dysplasia. Larger adenomas with severe dysplastic changes (sometimes called carcinoma in situ) carry a higher risk of progressing to invasive adenocarcinoma. Gastrointestinal adenomas may present as solitary or multifocal lesions. Familial adenomas tend to be multifocal and carry a higher risk of malignant transformation.
• digestive system neuroendocrine tumor g1 - a usually small, slow-growing, well differentiated neuroendocrine tumor arising from the digestive system. It is composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with small vesicular nuclei. The mitotic count is less than 2 per 10 hpf and/or the ki67 index is equal to or less than 2 percent. The tumor can occur anywhere in the digestive system; approximately 90% arise in the appendix.
• digestive system neuroendocrine tumor g2 - a well differentiated, intermediate grade tumor with neuroendocrine differentiation that arises from the digestive system. The mitotic count is 2-20 per 10 hpf and/or the ki67 index is 3 to 20 percent.
• disseminated juvenile xanthogranuloma - juvenile xanthogranuloma disseminated to extracutaneous sites including mucosal surfaces, lung, central nervous system, pituitary, lymph nodes, eye, liver, and bone marrow. It is characterized by the presence of lipid-laden, foamy histiocytes and touton-type giant cells forming nodules in the affected anatomic sites.
• distal bile duct carcinoma - a carcinoma that arises from the common bile duct distal to the insertion of the cystic duct.
• distal urethral carcinoma - a carcinoma that arises from the distal part of the urethra.
• duodenal adenocarcinoma - an adenocarcinoma that arises from the duodenum. Histologic variants include mucinous adenocarcinoma and signet ring cell carcinoma.
• dysembryoplastic neuroepithelial tumor - a benign glial-neuronal neoplasm. It is usually supratentorial, located in the cortex. It occurs in children and young adults with a long-standing history of partial seizures. A histologic hallmark of this tumor is the 'specific glioneuronal element', characterized by columns, made up of bundles of axons, oriented perpendicularly to the cortical surface. (adapted from who)
• dysgerminoma - a malignant germ cell tumor characterized by the presence of a monotonous primitive germ cell population. The neoplastic cells form aggregates and have an abundant pale cytoplasm and uniform nuclei. The aggregates of the germ cells are separated by fibrous septa which contain inflammatory cells, mostly t-lymphocytes. It arises primarily in the ovaries, but can occur both primarily and secondarily at other sites, particularly the central nervous system. It responds to chemotherapy and radiotherapy. Its prognosis is related to the tumor stage.
• dysplastic cerebellar gangliocytoma - a benign, who grade I cerebellar mass, which occurs in young adults and is composed of dysplastic ganglion cells. It is the major cns manifestation of cowden disease, an autosomal dominant condition that causes a variety of hamartomas and neoplasms.
• dysplastic nevus - solitary or multiple, slightly raised pigmented melanocytic lesions with irregular borders, usually measuring more than 0.6cm in greatest dimension. Morphologically, there is melanocytic atypia and the differential diagnosis from melanoma may be difficult. Patients are at an increased risk for the development of melanoma.
• ebv-positive diffuse large b-cell lymphoma, not otherwise specified - a diffuse large b-cell lymphoma originally described in patients older than 50 years but it has been increasingly recognized in younger patients. Epstein-barr virus is present in all cases. There is no known history of immunodeficiency or prior lymphoma.
• ebv-related clonal post-transplant lymphoproliferative disorder - a clonal lymphoproliferative disorder that develops following an organ transplantation and is caused by epstein-barr virus infection.
• ear carcinoma - a carcinoma that arises from the ear. Representative examples include ceruminous adenocarcinoma and squamous cell carcinoma of the external ear and adenocarcinoma of the middle ear.
• early gastric cancer - an invasive adenocarcinoma confined to the mucosa or mucosa and submucosa of the gastric wall. The regional lymph nodes may or may not be involved. It usually occurs in the lesser curvature. The 5-year survival rate following resection is between 80 percent and 95 percent, and remains high even when lymph node metastases are present.
• early hepatocellular carcinoma - a low grade, well differentiated small hepatocellular carcinoma. It lacks obvious stromal invasion and significant atypia.
• eccrine carcinoma - an adenocarcinoma with eccrine differentiation arising from the sweat glands. It includes the following subtypes: ductal eccrine adenocarcinoma, papillary eccrine carcinoma, and eccrine porocarcinoma.
• eccrine hidrocystoma - a benign sweat gland cystic lesion that arises from the dermis. It is lined by a thin epithelial layer of cells with a slightly eosinophilic cytoplasm.
• embryonal carcinoma - a non-seminomatous malignant germ cell tumor characterized by the presence of large germ cells with abundant cytoplasm resembling epithelial cells, geographic necrosis, high mitotic activity, and pseudoglandular and pseudopapillary structures formation. It can arise from the testis, ovary, and extragonadal sites (central nervous system and mediastinum).
• embryonal rhabdomyosarcoma - a poorly circumscribed morphologic variant of rhabdomyosarcoma. It is characterized by the presence of primitive skeletal muscle differentiation in any stage of myogenesis.
• embryonal tumor with multilayered rosettes, c19mc-altered - an aggressive malignant embryonal neoplasm arising from the central nervous system. It is characterized by the presence of multilayered rosettes formation and the presence of amplification of the c19mc region on chromosome 19 (19q13.42).
• encapsulated thymoma - a thymoma that is confined within the capsule and may display benign or malignant morphologic characteristics.
• enchondroma - a common benign hyaline cartilage neoplasm arising in the intramedullary bone. It is characterized by the presence of chondrocytes, low mitotic activity, and in some cases, a nodular pattern and calcification. The small bones of the hands and feet are the most frequently affected sites.
• endocervical carcinoma - an adenocarcinoma characterized by the presence of malignant glandular epithelium resembling the endocervical epithelium.
• endocervical polyp - a polyp that arises from the endocervix. It is characterized by the presence of endocervical glands and a fibrovascular stroma.
• endometrial adenocarcinoma - an adenocarcinoma arising from the uterine body cavity. This is the most frequent malignant tumor affecting the uterine body, and is linked to estrogen therapy. Most patients present with uterine bleeding and are over age 40 at the time of diagnosis. The prognosis depends on the stage of the tumor, the depth of the uterine wall invasion, and the histologic subtype. Endometrioid adenocarcinoma is the most frequently seen morphologic variant of endometrial adenocarcinoma.
• endometrial adenosquamous carcinoma - a rare endometrial carcinoma characterized by the presence of both malignant glandular and malignant squamous cellular components.
• endometrial carcinoma - a malignant tumor arising from the epithelium that lines the cavity of the uterine body. The vast majority of endometrial carcinomas are adenocarcinomas; squamous cell and adenosquamous carcinomas represent a minority of the cases. Endometrioid adenocarcinoma is the most frequently seen variant of endometrial adenocarcinoma. Uterine bleeding is an initial clinical sign. The prognosis depends on the stage of the tumor, the depth of myometrial wall invasion, and the degree of differentiation.
• endometrial clear cell adenocarcinoma - a high-grade endometrial adenocarcinoma characterized by the presence of large neoplastic cells that display at least focal cytoplasmic clearing. The neoplastic cells form papillary, glandular, or sheet-like structures.
• endometrial endometrioid adenocarcinoma - a primary endometrial adenocarcinoma composed of neoplastic cells that form complex glandular patterns associated with budding and branching of the neoplastic glands. The neoplastic glands resemble those of the normal endometrium and may or may not be associated with sheet-like proliferation of malignant cells. Endometrioid adenocarcinoma is the most commonly seen morphologic variant of endometrial adenocarcinoma.
• endometrial mucinous adenocarcinoma - a primary, usually low grade adenocarcinoma of the endometrium in which the majority of the malignant epithelial cells contain abundant intracytoplasmic mucin.
• endometrial serous adenocarcinoma - a high grade, aggressive adenocarcinoma arising from the endometrium. It is characterized by the presence of complex papillary patterns with cellular budding. Atypical mitoses, necrosis, and psammoma bodies may be present. It is classified as type ii endometrial carcinoma and it is not associated with endometrial hyperplasia. It tends to invade deeply into the myometrium and spreads into the lymphatic vessels. Patients frequently present with spread of the tumor beyond the uterus at the time of diagnosis. The prognosis is usually poor.
• endometrial small cell carcinoma - a primary carcinoma of the endometrium that is similar to the small cell carcinoma of the lung, histologically.
• endometrial squamous cell carcinoma - a primary carcinoma of the endometrium characterized by the presence of malignant squamous cells.
• endometrioid stromal sarcoma - a malignant mesenchymal neoplasm that affects the uterine corpus, and rarely, the ovaries, cervix, and vagina. In the uterine corpus it is classified as low grade or high grade endometrial stromal sarcoma. In the remainder of the anatomic sites it is classified as low grade endometrioid stromal sarcoma.
• enteropathy-associated t-cell lymphoma - a mature t-cell and nk-cell non-hodgkin lymphoma of intraepithelial t-lymphocytes. It usually arises from the small intestine, most commonly the jejunum or ileum. Other less frequent primary anatomic sites include the duodenum, stomach, colon, or outside the gastrointestinal tract. It is characterized by the presence of pleomorphic medium-sized to large t-lymphocytes with vesicular nuclei, prominent nucleoli, and moderate to abundant pale cytoplasm. It is associated with celiac disease.
• eosinophilic granuloma - a clinical variant of langerhans cell histiocytosis characterized by unifocal involvement of a bone (most often), skin, or lung. Patients are usually older children or adults usually presenting with a lytic bone lesion. The etiology is unknown. Morphologically, eosinophilic granuloma is characterized by the presence of langerhans cells in a characteristic milieu which includes histiocytes, eosinophils, neutrophils, and small, mature lymphocytes.
• ependymal tumor - a group of neoplasms which arise from the ependymal lining of the cerebral ventricles and from the remnants of the central canal of the spinal cord. Ependymal tumors occur predominantly in children and young adults with varied morphological features and biological behavior. There are 4 types: ependymoma, anaplastic ependymoma, myxopapillary ependymoma and subependymoma. (who)
• ependymoma - a who grade ii, slow growing tumor of children and young adults, usually located intraventricularly. It is the most common ependymal neoplasm. It often causes clinical symptoms by blocking cerebrospinal fluid pathways. Key histological features include perivascular pseudorosettes and ependymal rosettes. (who)
• ependymoma, rela fusion-positive - an ependymoma characterized by gene fusions involving rela, a transcription factor involved in nk-kb pathway activity. It accounts for the majority of supratentorial ependymomas in children. It has an unfavorable outcome when compared to other ependymoma subtypes.
• epipodophyllotoxin-related myelodysplastic syndrome - a disorder seen following cancer chemotherapy. It typically manifests a few years after initiation of epipodophyllotoxin chemotherapy. Mutagenic potential of these non-intercalating dna topoisomerase ii inhibitors is believed to be increased with concurrent use of asparaginase or granulocyte colony-stimulating factor. Balanced translocations involving chromosomal bands 11q23 and 21q22 are commonly associated with this disorder. Clinical signs may include fatigue, dyspnea, bruising and frequent infections. Clinical course usually progresses to acute myeloid leukemia though most epipodophyllotoxin-related leukemias do not have an antecedent myelodysplastic phase. Prognosis is dismal with survivability usually less than one year.
• epithelial predominant kidney wilms tumor - wilms tumor of the kidney characterized by the predominance of the epithelial component. The epithelial cells may form papillary and tubular patterns and pseudorosettes.
• epithelial-myoepithelial carcinoma - a malignant neoplasm which occurs mostly in the major salivary glands (most frequently in the parotid gland), but also in the minor salivary glands of the oral mucosa and the tracheobronchial tree. It is characterized by the presence of ductal structures which are lined by an inner layer of cuboidal epithelial-type cells and an outer layer of myoepithelial cells with clear or eosinophilic cytoplasm.
• epithelioid cell melanoma - a melanoma characterized by the presence of malignant large epithelioid melanocytes.
• epithelioid hemangioendothelioma - a low-grade malignant blood vessel neoplasm. It is characterized by the presence of epithelioid endothelial cells. The neoplastic cells are arranged in cords and nests, which are embedded in a myxoid to hyalinized stroma.
• epithelioid leiomyosarcoma - a morphologic variant of leiomyosarcoma characterized by the presence of epithelioid round cells with eosinophilic to clear cytoplasm.
• epithelioid malignant peripheral nerve sheath tumor - a rare variant of malignant peripheral nerve sheath tumor composed predominantly or exclusively of epithelioid cells.
• epithelioid mesothelioma - a malignant neoplasm arising from mesothelial cells. It is characterized by the presence of cells with epithelioid morphology. The epithelioid cells usually have eosinophilic cytoplasm, bland nuclei, and form tubulopapillary, microglandular, or sheet-like patterns.
• esophageal adenocarcinoma - a malignant tumor with glandular differentiation arising predominantly from barrett mucosa in the lower third of the esophagus. Rare examples of esophageal adenocarcinoma deriving from ectopic gastric mucosa in the upper esophagus have also been reported. Grossly, esophageal adenocarcinomas are similar to esophageal squamous cell carcinomas. Microscopically, adenocarcinomas arising in the setting of barrett esophagus are typically papillary and/or tubular. The prognosis is poor.
• esophageal carcinoma - a malignant epithelial tumor arising from the esophageal mucosa. Two major histologic types of esophageal carcinoma have been described: squamous cell carcinoma and adenocarcinoma. This type of cancer is associated with excessive ethanol and cigarette usage.
• esophageal moderately differentiated squamous cell carcinoma - an esophageal squamous cell carcinoma characterized by the presence of variable morphologic characteristics that include areas of prominent and poor keratinization.
• esophageal poorly differentiated squamous cell carcinoma - an esophageal squamous cell carcinoma characterized by the presence of basal-like malignant squamous cells that form nests, often associated with central necrosis.
• esophageal small cell carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the esophagus. It is characterized by the presence of malignant small cells.
• esophageal squamous cell carcinoma - a squamous cell carcinoma arising from the esophagus. It is associated with a long history of tobacco and alcohol abuse and is exceedingly rare before the age of 30. The median age is around 65 in both males and females. It is located mostly in the middle and lower third of the esophagus. Grossly, polypoid, ulcerated, plaque-like and occult lesions have been described. The microscopic features are the same as in other squamous cell carcinomas. Any degree of differentiation may occur, and variation within a single tumor is common. The prognosis is poor.
• esophageal well differentiated squamous cell carcinoma - an esophageal squamous cell carcinoma characterized by the presence of prominent keratinization and low mitotic activity.
• essential thrombocythemia - a chronic myeloproliferative neoplasm that involves primarily the megakaryocytic lineage. It is characterized by sustained thrombocytosis in the blood, increased numbers of large, mature megakaryocytes in the bone marrow, and episodes of thrombosis and/or hemorrhage. (who, 2008)
• ewing sarcoma - a small round cell tumor that lacks morphologic, immunohistochemical, and electron microscopic evidence of neuroectodermal differentiation. It represents one of the two ends of the spectrum called ewing sarcoma/peripheral neuroectodermal tumor. It affects mostly males under age 20, and it can occur in soft tissue or bone. Pain and the presence of a mass are the most common clinical symptoms.
• ewing sarcoma of bone - a small round cell bone tumor that lacks morphologic, immunohistochemical, and electron microscopic evidence of neuroectodermal differentiation. It represents one of the two ends of the spectrum called ewing sarcoma/peripheral neuroectodermal tumor. It often affects the diaphysis or metaphyseal-diaphyseal portion of long bones. Clinical findings include pain and a mass in the involved area. Fever, anemia, leukocytosis, and an increased sedimentation rate are often seen. X-ray examination reveals osteolytic lesions. The prognosis depends on the stage, anatomic location, and size of the tumor.
• ewing sarcoma/peripheral primitive neuroectodermal tumor - a spectrum of malignant tumors, affecting mostly males under age 20, characterized morphologically by the presence of small round cells. Ewing sarcoma and peripheral primitive neuroectodermal tumor represent the ends of a spectrum, with ewing sarcoma lacking evidence of neural differentiation and the markers that characterize the peripheral primitive neuroectodermal tumor. Ewing sarcoma and peripheral primitive neuroectodermal tumor may share cytogenetic abnormalities, proto-oncogene expression, cell culture and immunohistochemical abnormalities. These tumors may occur in the soft tissues or the bones. Pain and the presence of a mass are the most common clinical symptoms.
• ewing sarcoma/peripheral primitive neuroectodermal tumor of bone - a spectrum of malignant tumors arising from the bone and characterized morphologically by the presence of small round cells. Ewing sarcoma and peripheral primitive neuroectodermal tumor represent the ends of a spectrum, with ewing sarcoma lacking evidence of neural differentiation and the markers that characterize the peripheral primitive neuroectodermal tumor. Ewing sarcoma and peripheral primitive neuroectodermal tumor may share cytogenetic abnormalities, proto-oncogene expression, cell culture and immunohistochemical abnormalities. Pain and the presence of a mass are the most common clinical symptoms.
• exocervical carcinoma - a carcinoma that arises from the squamous epithelium of the exocervix.
• external ear carcinoma - a carcinoma that arises from the external ear. This category includes squamous cell carcinoma, basal cell carcinoma, and ceruminous adenocarcinoma.
• extracardiac rhabdomyoma - a benign mesenchymal neoplasm that shows mature skeletal muscle differentiation.
• extracranial neuroblastoma - a neuroblastoma arising from an anatomic site other than the brain.
• extragonadal germ cell tumor - a germ cell tumor arising in an anatomic site other than the testis or ovary (e.G., central nervous system, lung, mediastinum, and retroperitoneum).
• extrahepatic bile duct adenocarcinoma - an adenocarcinoma arising from the epithelium of the extrahepatic bile ducts. Signs and symptoms include abdominal pain, anorexia, jaundice, pruritus, nausea and vomiting, and weight loss.
• extrahepatic bile duct carcinoma - a carcinoma that arises from the extrahepatic bile ducts. The majority are adenocarcinomas.
• extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue - an indolent, extranodal type of non-hodgkin lymphoma composed of small b-lymphocytes (centrocyte-like cells). The gastrointestinal tract is the most common site of involvement. Other common sites of involvement include lung, head and neck, ocular adnexae, skin, thyroid, and breast. Gastric involvement is associated with the presence of h. Pylori infection. (who, 2001)
• extraocular retinoblastoma - retinoblastoma that has spread beyond the eye e.G. To brain, soft tissue/bone, bone marrow.
• extraosseous plasmacytoma - a plasma cell neoplasm arising at an extraosseous site. There is no involvement of the bone marrow. It most frequently involves the oropharynx, nasopharynx, sinuses, and larynx. Other sites of involvement include the gastrointestinal tract, central nervous system, breast, skin, lymph nodes, and bladder. A minority of patients have a monoclonal gammopathy. Treatment includes radiation therapy. Progression to plasma cell myeloma occurs in a minority of patients.
• extrarenal rhabdoid tumor - a rhabdoid tumor which arises in the soft tissues. It occurs in infants and children and may be associated with loss of chromosome 22. It is characterized by the presence of cells with a large eccentric nucleus, prominent nucleolus, and abundant cytoplasm.
• extraskeletal ewing sarcoma - a rare malignant neoplasm of the soft tissues. It is typically a disease of children and young adults. Most commonly occurs in the paravertebral region, chest wall, pelvis and lower extremities. Treatment includes local excision with consideration for post-operative chemotherapy and/or radiotherapy.
• extraskeletal ewing sarcoma/peripheral primitive neuroectodermal tumor - a spectrum of malignant tumors arising from the soft tissues, characterized morphologically by the presence of small round cells. Ewing sarcoma and peripheral primitive neuroectodermal tumor represent the ends of a spectrum, with ewing sarcoma lacking evidence of neural differentiation and the markers that characterize the peripheral primitive neuroectodermal tumor. Ewing sarcoma and peripheral primitive neuroectodermal tumor may share cytogenetic abnormalities, proto-oncogene expression, cell culture and immunohistochemical abnormalities. Pain and the presence of a mass are the most common clinical symptoms.
• extraskeletal osteosarcoma - an osteosarcoma arising from the soft tissue.
• extraventricular neurocytoma - a who grade ii neoplasm that arises from the brain parenchyma. Morphologically it is characterized by the presence of neoplastic uniform, round cells with neuronal differentiation. Unlike central neurocytoma, it does not involve the lateral ventricles. It usually affects young adults and has a favorable prognosis.
• eye carcinoma - a carcinoma that arises from any of the structures of the eye.
• eyelid carcinoma - a carcinoma that arises from the eyelid. Examples include basal cell carcinoma and squamous cell carcinoma.
• fsh-producing gonadotroph adenoma - an adenoma of the anterior lobe of the pituitary gland that produces follicle-stimulating hormone (fsh).
• fallopian tube adenocarcinoma - an adenocarcinoma that arises from the fallopian tube. Histologic subtypes include clear cell, endometrioid, serous, and mucinous adenocarcinoma. It spreads to adjacent organs, regional lymph nodes, and peritoneum.
• fallopian tube carcinoma - a carcinoma arising from the fallopian tube. Most patients are postmenopausal, and postmenopausal bleeding is the most frequently seen symptom. Morphologically, the majority of fallopian tube carcinomas are serous or endometrioid adenocarcinomas.
• fallopian tube squamous cell carcinoma - a rare squamous cell carcinoma that arises from the fallopian tube.
• familial neuroblastoma - neuroblastoma inherited from a parent and caused by mutations in the alk or phox2b genes. Familial neuroblastomas have a higher incidence of multiple primary tumors and are diagnosed at an earlier age.
• familial nonmedullary thyroid gland carcinoma - a papillary or follicular thyroid gland carcinoma with a genetic component that develops within the same family. Current studies suggest that it is inherited in an autosomal dominant pattern. It is often multifocal and bilateral and usually affects younger patients.
• familial waldenstrom macroglobulinemia - waldenstrom macroglobulinemia in a patient who has at least one first degree relative with either waldenstrom macroglobulinemia or another b-cell lymphoproliferative disorder.
• female breast carcinoma - a carcinoma that arises from the breast in females. It is the most common malignant tumor that affects females.
• fibrillary astrocytoma - the most frequent histological variant of diffuse astrocytoma. It is predominantly composed of fibrillary neoplastic astrocytes. Nuclear atypia is a diagnostic criterion but mitotic activity, necrosis and microvascular proliferation are absent. The occasional or regional occurrence of gemistocytic neoplastic cells is compatible with the diagnosis of fibrillary astrocytoma. (who)
• fibroblastic osteosarcoma - a conventional osteosarcoma characterized by the presence of spindle shaped cells.
• fibroblastic reticular cell tumor - a very rare dendritic cell tumor affecting the lymph nodes, spleen, and soft tissues. Morphologically it is similar to the interdigitating dendritic cell sarcoma or follicular dendritic cell sarcoma. The tumor cells are positive for cytokeratin and cd68. Clinical outcome is variable.
• fibrolamellar carcinoma - a distinctive type of liver cell carcinoma that arises in non-cirrhotic livers and is seen predominantly in young patients. The tumor cells are polygonal and deeply eosinophilic, and are embedded in a fibrous stroma. The prognosis is similar to classical hepatocellular carcinoma that arises in non-cirrhotic livers, and better than hepatocellular carcinoma that arises in cirrhotic livers.
• fibrosarcoma - a malignant mesenchymal fibroblastic neoplasm affecting the soft tissue and bone.
• fibrous meningioma - a who grade I meningioma characterized by the presence of spindle cells that form bundles in a collagen matrix.
• flat adenoma - an adenoma of the gastrointestinal tract mucosa which grossly and morphologically does not appear as an elevated or polypoid lesion.
• floor of mouth squamous cell carcinoma - a squamous cell carcinoma of the oral cavity that arises from the floor of the mouth.
• follicular dendritic cell sarcoma - a neoplasm composed of spindle to ovoid cells which have morphologic and immunophenotypic characteristics of follicular dendritic cells. It affects lymph nodes and other sites including the tonsils, gastrointestinal tract, spleen, liver, soft tissues, skin, and oral cavity. It usually behaves as a low grade sarcoma. Treatment options include complete surgical removal of the tumor with or without adjuvant chemotherapy or radiotherapy. Recurrences have been reported in up to half of the cases.
• follicular lymphoma - a neoplasm of follicle centre b cells which has at least a partial follicular pattern. Follicular lymphomas comprise about 35% of adult non-hodgkin lymphomas in the u.S. And 22% worldwide. Most patients have widespread disease at diagnosis. Morphologically, follicular lymphomas are classified as grade 1, grade 2, and grade 3, depending on the percentage of the large lymphocytes present. The vast majority of cases (70-95%) express the bcl-2 rearrangement [t(14;18)]. Histological grade correlates with prognosis. Grades 1 and 2 follicular lymphomas are indolent and grade 3 is more aggressive (adapted from who, 2001).
• follicular t-cell lymphoma - a lymph node-based peripheral t-cell lymphoma of t-follicular helper (tfh) cells, with a predominantly follicular growth pattern. It lacks characteristic features of angioimmunoblastic t-cell lymphoma such as proliferation of high endothelial venules or extrafollicular follicular dendritic cells. (who 2017)
• functioning pituitary gland adenoma - a hormone producing pituitary gland adenoma, associated with a hormonal syndrome.
• fusion-negative rhabdomyosarcoma - a rhabdomyosarcoma characterized by the absence of chromosomal translocation t(1;13)(p36;q14) or t(2;13)(q35;q14) and therefore the absence of pax7-foxo1 or pax3-foxo1 gene fusion.
• fusion-positive rhabdomyosarcoma - a rhabdomyosarcoma characterized by the presence of chromosomal translocation t(1;13)(p36;q14) that results in pax7-foxo1 gene fusion; or translocation t(2;13)(q35;q14) that results in pax3-foxo1 gene fusion.
• gallbladder adenocarcinoma - an adenocarcinoma arising from the gallbladder. It is the most common malignant tumor of the gallbladder and it is usually well to moderately differentiated. The incidence is higher in patients with gallstones than in patients without gallstones. Signs and symptoms usually present late in the course of the disease and are reminiscent of those of chronic cholecystitis including right upper quadrant pain. Histologic variants include adenocarcinoma of the intestinal type, clear cell adenocarcinoma, mucinous adenocarcinoma, papillary adenocarcinoma, and signet ring adenocarcinoma.
• gallbladder adenoma - a polypoid epithelial neoplasm that arises from the gallbladder. According to the neoplastic growth pattern, it is classified as tubular, tubulopapillary, or papillary.
• gallbladder adenosquamous carcinoma - a carcinoma that arises from the gallbladder. It is characterized by the presence of glandular and squamous malignant epithelial components.
• gallbladder carcinoma - a malignant tumor arising from the epithelium of the gallbladder. It is usually associated with the presence of gallstones. Clinical symptoms are not specific and usually present late in the course. Morphologically, most gallbladder carcinomas are adenocarcinomas; squamous cell carcinomas, adenosquamous carcinomas, signet ring carcinomas, and undifferentiated carcinomas can also occur.
• gallbladder intracholecystic papillary neoplasm with an associated invasive carcinoma - an intracholecystic papillary neoplasm, usually with high grade intraepithelial neoplasia, that arises from the gallbladder. It is associated with the presence of an invasive carcinoma. The carcinomatous component is an adenocarcinoma.
• gallbladder small cell carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the gallbladder. It is characterized by the presence of malignant small cells.
• gallbladder squamous cell carcinoma - a carcinoma that arises from the gallbladder. It is composed entirely by malignant squamous epithelial cells.
• gamma heavy chain disease - a clonal disorder characterized by the secretion of a truncated gamma chain. In most cases, it is associated with morphologic changes also seen in lymphoplasmacytic lymphomas, but the clinical course is typically more aggressive than in lymphoplasmacytic lymphoma.
• gangliocytoma - a well differentiated, slow growing neuroepithelial neoplasm composed of neoplastic, mature ganglion cells.
• ganglioglioma - a well differentiated, slow growing neuroepithelial neoplasm composed of neoplastic, mature ganglion cells and neoplastic glial cells. Some gangliogliomas show anaplastic features in their glial component and are considered to be who grade iii. Rare cases of newly diagnosed gangliogliomas with grade iv (glioblastoma) changes in the glial component have also been reported. (adapted from who)
• ganglioneuroblastoma - a neuroblastic tumor characterized by the presence of neuroblastic cells, ganglion cells, and a stroma with schwannian differentiation constituting more than fifty-percent of the tumor volume. There are two histologic subtypes identified: ganglioneuroblastoma, intermixed and ganglioneuroblastoma, nodular.
• ganglioneuroblastoma, intermixed - a ganglioneuroblastoma characterized by the presence of neuroblastic cells in a schwannian stroma, without the presence of hemorrhagic neuroblastic nodules.
• ganglioneuroblastoma, nodular - a ganglioneuroblastoma characterized by the presence of neuroblastic cells in a schwannian stroma, and the formation of hemorrhagic neuroblastic nodules.
• ganglioneuroma - a benign neuroblastic tumor of the sympathetic nervous system that occurs in childhood. Ganglioneuroma typically arises from the sympathetic trunk in the mediastinum. Histologic features include spindle cell proliferation (resembling a neurofibroma) and the presence of large ganglion cells. Common presenting features include a palpable abdominal mass, hepatomegaly, and a thoracic mass detected on routine chest x-ray.
• gastric adenocarcinoma - an adenocarcinoma arising from the stomach glandular epithelium. Gastric adenocarcinoma is primarily a disease of older individuals. It most commonly develops after a long period of atrophic gastritis and is strongly associated with helicobacter pylori infection. The lack of early symptoms often delays the diagnosis of gastric cancer. The majority of patients present with advanced tumors which have poor rates of curability. Microscopically, two important histologic types of gastric adenocarcinoma are recognized: the intestinal and diffuse type. The overall prognosis of gastric adenocarcinomas is poor, even in patients who receive a "Curative" resection (adapted from sternberg's surgical pathology, 3rd ed., 1999).
• gastric adenoma - a neoplastic polyp that arises from the stomach. This category includes intestinal-type adenomatous polyps, gastric-type adenomas, and fundic gland polyps.
• gastric adenosquamous carcinoma - a carcinoma that arises from the stomach and is characterized by the presence of malignant cells with glandular and squamous differentiation.
• gastric carcinoma - a malignant epithelial tumor of the stomach mucosa. The vast majority of gastric carcinomas are adenocarcinomas, arising from the gastric glandular epithelium.
• gastric diffuse adenocarcinoma - an adenocarcinoma arising from the stomach. Microscopically, it is characterized by the presence of a diffuse infiltrate, composed of individual adenocarcinoma cells or groups of adenocarcinoma cells in a fibrous or mucoid stroma. Many cells contain mucin droplets, producing a signet-ring configuration.
• gastric intestinal-type adenocarcinoma - an adenocarcinoma of the stomach arising on a background of intestinal metaplasia. Microscopically, it is characterized by a glandular pattern and it closely resembles a colonic adenocarcinoma. Grossly, it tends to be nodular, polypoid or ulcerated.
• gastric intramucosal adenocarcinoma - a neoplasm that arises from the gastric glandular epithelium and invades the lamina propria but not the submucosa. There is marked glandular crowding, branching and budding, intraluminal necrosis, and prominent mitotic activity. Desmoplastic changes may be present or absent.
• gastric mucinous adenocarcinoma - a variant of gastric adenocarcinoma with more than half of the tumor containing extracellular mucinous pools.
• gastric mucosa-associated lymphoid tissue lymphoma - a low grade, indolent b-cell lymphoma, usually associated with helicobacter pylori infection. Morphologically it is characterized by a dense mucosal atypical lymphocytic (centrocyte-like cell) infiltrate with often prominent lymphoepithelial lesions and plasmacytic differentiation. Approximately 40% of gastric malt lymphomas carry the t(11;18)(q21;q21). Such cases are resistant to helicobacter pylori therapy.
• gastric poorly cohesive adenocarcinoma - an adenocarcinoma that arises from the gastric mucosa and is characterized by the presence of isolated malignant cells or malignant cells that form small aggregates. This category includes signet ring cell adenocarcinomas, adenocarcinomas that are composed of malignant cells resembling lymphocytes and histiocytes, and adenocarcinomas that are composed of malignant cells with deeply eosinophilic cytoplasm.
• gastric signet ring cell adenocarcinoma - a poorly cohesive gastric adenocarcinoma characterized by malignant cells containing intracytoplasmic mucin.
• gastric small cell carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the stomach. It is characterized by the presence of malignant small cells.
• gastric squamous cell carcinoma - a rare carcinoma of the stomach resembling squamous cell carcinomas arising elsewhere in the body.
• gastric undifferentiated carcinoma - a carcinoma that arises from the stomach and is characterized by the absence of microscopic features of glandular or squamous differentiation.
• gastroesophageal junction adenocarcinoma - an adenocarcinoma that arises from and straddles the junction of the stomach and esophagus. The category of adenocarcinomas of the gastroesophageal junction also includes the majority of adenocarcinomas previously called gastric cardia adenocarcinomas. Squamous cell carcinomas that affect or cross the junction of the stomach and esophagus are classified as carcinomas of the distal esophagus. Adenocarcinoma of the gastroesophageal junction occurs more often in caucasian middle aged and elderly males. Clinical signs and symptoms include dysphagia, abdominal pain, and weight loss. The prognosis depends on the completeness of the surgical resection, the number of lymph nodes involved by cancer, and the presence or absence of postoperative complications. The presence of tp53 mutations indicates worse prognosis.
• gastrointestinal stromal tumor - a stromal tumor most commonly seen in the gastrointestinal tract. Rare cases of solitary masses in the omentum or the mesentery have also been reported (extragastrointestinal gastrointestinal stromal tumor). It is a tumor that differentiates along the lines of interstitial cells of cajal. Most cases contain kit- or pdgfra-activating mutations. Until recently, surgery has been the only effective therapy for this tumor. However, many patients still experience recurrence. Conventional chemotherapy and radiation therapy have been of limited value. A kit tyrosine kinase inhibitor, imatinib mesylate (also known as sti-571 or gleevec), is now effective in the treatment of relapsed and unresectable cases.
• gastrointestinal stromal tumor of uncertain malignant potential - a gastrointestinal stromal tumor that is characterized by a maximum diameter greater than 5 cm and equal or less than 10 cm (gastric localization), or greater than 2 cm and equal or less than 5 cm (intestinal localization) and no more than 5 mitotic figures per 50 high power fields.
• gemistocytic astrocytoma - a rare variant of diffuse astrocytoma. It is characterized by the presence of a conspicuous, though variable, fraction of gemistocytic neoplastic astrocytes. Gemistocytes are round to oval astrocytes with abundant, glassy, non-fibrillary cytoplasm which appears to displace the dark, angulated nucleus to the periphery of the cell. To make the diagnosis of gemistocytic astrocytoma, gemistocytes should amount to more than approximately 20% of all tumor cells. (adapted from who)
• gemistocytic astrocytoma, idh-mutant - gemistocytic astrocytoma carrying idh mutations.
• germ cell tumor - a benign or malignant, gonadal or extragonadal neoplasm that originates from germ cells. Representative examples include teratoma, seminoma, embryonal carcinoma, and yolk sac tumor.
• germinoma - a malignant germ cell tumor arising in the central nervous system. It is characterized by the presence of primitive, large malignant germ cells and lymphocytes.
• gestational choriocarcinoma - a rare, highly malignant epithelial tumor that develops from a hydatidiform mole (50%), following abortion (25%), or during normal pregnancy (22%). It is characterized by the presence of invasive and anaplastic trophoblastic tissue composed of intermediate trophoblastic cells, cytotrophoblasts and syncytiotrophoblasts, abundant vascularity, and secretion of human chorionic gonadotropin. Because of rapid growth and a high propensity for hemorrhage, this neoplasm often constitutes a medical emergency.
• gestational trophoblastic tumor - a diverse group of pregnancy-related tumors characterized by excessive proliferation of trophoblasts. Representative examples include gestational choriocarcinoma and placental site trophoblastic tumor.
• giant cell carcinoma - a malignant epithelial neoplasm composed of giant, pleomorphic cells.
• giant cell fibroblastoma - a rare, locally aggressive fibroblastic neoplasm typically affecting young patients (predominantly boys). It manifests with painless nodules in the dermis or subcutaneous tissues. Morphologically, it contains giant cells and wide vessel-like spaces. This tumor can recur but metastases have not been reported.
• giant cell glioblastoma - a rare histological variant of glioblastoma (who grade iv) with a predominance of bizarre, multinucleated giant cells, an occasionally abundant stromal reticulin network, and a high frequency of tp53 mutations. (who)
• giant cell tumor - a benign, intermediate, or malignant tumor that arises from the bone or soft tissue. It is characterized by the presence of multinucleated osteoclast-like giant cells.
• giant cell tumor of soft tissue - a painless, well circumscribed tumor arising in soft tissue, usually of the upper and lower extremities. Morphologically, it is characterized by a multinodular growth pattern. The cellular infiltrate is composed of mononuclear round or oval cells and multinucleated osteoclast-like giant cells, in a rich vascular stroma. It rarely metastasizes.
• gingival spindle cell carcinoma - a poorly differentiated squamous cell carcinoma that arises from the gingiva. It is characterized by the presence of malignant pleomorphic spindle cells.
• gingival squamous cell carcinoma - a squamous cell carcinoma that arises from the gingival mucosa. It presents as an ulcerated lesion or exophytic mass. The prognosis is usually poor.
• glandular malignant peripheral nerve sheath tumor - a variant of malignant peripheral nerve sheath tumor characterized by the presence of glandular epithelium.
• glioblastoma - the most malignant astrocytic tumor (who grade iv). It is composed of poorly differentiated neoplastic astrocytes and it is characterized by the presence of cellular polymorphism, nuclear atypia, brisk mitotic activity, vascular thrombosis, microvascular proliferation and necrosis. It typically affects adults and is preferentially located in the cerebral hemispheres. It may develop from diffuse astrocytoma who grade ii or anaplastic astrocytoma (secondary glioblastoma, idh-mutant), but more frequently, it manifests after a short clinical history de novo, without evidence of a less malignant precursor lesion (primary glioblastoma, idh- wildtype). (adapted from who)
• glioblastoma by gene expression profile - classification of glioblastoma into molecular subtypes as defined by gene expression profiling.
• glioblastoma, idh-wildtype - a glioblastoma that arises de novo. It is more commonly seen in older patients. Mutations in idh1 or idh2 genes are not present.
• glioblastoma, not otherwise specified - glioblastoma in which there is insufficient information on the idh genes status.
• gliofibroma - an astrocytic tumor affecting young people. Morphologically, it is characterized by the presence of collagenous tissue surrounding neoplastic astrocytes. In some cases the collagen is produced by the tumor cells (desmoplastic astrocytoma), whereas in others it is produced by mesenchymal cells (mixed glioma/fibroma).
• glioma - a benign or malignant brain and spinal cord tumor that arises from glial cells (astrocytes, oligodendrocytes, ependymal cells). Tumors that arise from astrocytes are called astrocytic tumors or astrocytomas. Tumors that arise from oligodendrocytes are called oligodendroglial tumors. Tumors that arise from ependymal cells are called ependymomas.
• gliomatosis cerebri - a diffuse glial tumor which infiltrates the brain extensively, involving more than two lobes. It is frequently bilateral and often extends to the infratentorial structures, even to the spinal cord. It is probably of astrocytic origin, although gfap expression may be scant or absent. (adapted from who.)
• glioneuronal tumor with neuropil-like islands - a rare, who grade ii or iii infiltrating astrocytoma characterized by the presence of sharply demarcated foci, composed of a neuropil-like matrix.
• gliosarcoma - a rare histological variant of glioblastoma (who grade iv) characterized by a biphasic tissue pattern with alternating areas displaying glial and mesenchymal differentiation (who).
• glomus tumor - a rare benign or malignant mesenchymal neoplasm arising from cells that resemble the modified smooth muscle cells of the glomus body. The majority of glomus tumors occur in the distal extremities.
• glottic squamous cell carcinoma - a squamous cell carcinoma of the larynx that arises from the glottic area. It may remain localized for a long period then in late disease stage, it may spread to the opposite true vocal cord, supraglottic and subglottic areas, and the soft tissues of the neck. Hoarseness is the presenting symptom.
• gonadal polyembryoma - a rare malignant germ cell tumor arising from the testis and less often from the ovary. It is characterized by the presence of embryoid bodies which resemble early embryos.
• gonadoblastoma - a mixed germ cell/sex cord-stromal tumor characterized by the presence of large germ cells which resemble seminoma cells and small cells which resemble sertoli or granulosa cells. It occurs in the testis and the ovary and is identified in children and adults. It is often associated with gonadal dysgenesis and abnormal karyotype.
• gonadotroph adenoma - an adenoma of the anterior lobe of the pituitary gland that produces gonadotrophic hormones (fsh and/or lh) or shows evidence towards gonadotroph differentiation. The majority of cases are hormonally non-functional. Clinical manifestations include visual disturbances, hypopituitarism, headache, and acute hemorrhagic necrosis of the pituitary gland.
• grade 1 colon adenocarcinoma - a colon adenocarcinoma characterized by the presence of a malignant cellular infiltrate with more than 95% glandular formation.
• grade 1 colorectal adenocarcinoma - a colorectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with more than 95% glandular formation.
• grade 1 follicular lymphoma - a follicular lymphoma which contains up to 5 centroblasts per 40x high-power microscopic field.
• grade 1 rectal adenocarcinoma - a rectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with more than 95% glandular formation.
• grade 2 colon adenocarcinoma - a colon adenocarcinoma characterized by the presence of a malignant cellular infiltrate with 50-95% glandular formation.
• grade 2 colorectal adenocarcinoma - a colorectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with 50-95% glandular formation.
• grade 2 follicular lymphoma - a follicular lymphoma which contains 6-15 centroblasts per 40x high-power microscopic field.
• grade 2 rectal adenocarcinoma - a rectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with 50-95% glandular formation.
• grade 3 colon adenocarcinoma - a colon adenocarcinoma characterized by the presence of a malignant cellular infiltrate with less than 50% glandular formation.
• grade 3 colorectal adenocarcinoma - a colorectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with less than 50% glandular formation.
• grade 3 follicular lymphoma - a follicular lymphoma which contains more than 15 centroblasts per 40x high-power microscopic field.
• grade 3 rectal adenocarcinoma - a rectal adenocarcinoma characterized by the presence of a malignant cellular infiltrate with less than 50% glandular formation.
• grade I lymphomatoid granulomatosis - lymphomatoid granulomatosis characterized by the presence of a polymorphous lymphoid infiltrate without cytologic atypia. Large lymphocytes are absent or rare. By in situ hybridization, ebv-positive cells are infrequently seen.
• grade I meningioma - a benign meningioma which may recur in approximately 7-20% of the cases. This category includes the angiomatous meningioma, fibrous meningioma, lymphoplasmacyte-rich meningioma, meningothelial meningioma, metaplastic meningioma, microcystic meningioma, psammomatous meningioma, secretory meningioma, and transitional meningioma.
• grade ii lymphomatoid granulomatosis - lymphomatoid granulomatosis characterized by the presence of occasional large lymphoid cells or immunoblasts in a polymorphous background. Necrosis is more commonly seen as compared to grade I lymphomatoid granulomatosis. By in situ hybridization, ebv-positive cells are readily seen.
• grade ii meningioma - an atypical meningioma which may recur in approximately 29-40% of the cases. This category includes the atypical meningioma, chordoid meningioma, and clear cell meningioma.
• grade iii lymphomatoid granulomatosis - lymphomatoid granulomatosis characterized by the presence of aggregates of neoplastic large b-lymphocytes, usually admixed with pleomorphic and hodgkin-like cells, in a background of chronic inflammation. Necrotic changes are present and are usually extensive. Grade iii lymphomatoid granulomatosis should be approached clinically as a subtype of diffuse large b-cell lymphoma.
• grade iii meningioma - a malignant meningioma with aggressive clinical course. It recurs in approximately 50-78% of the cases. This category includes the anaplastic (malignant) meningioma, papillary meningioma, and rhabdoid meningioma.
• granular cell tumor - an unusual benign or malignant neoplasm characterized by the presence of neoplastic large polygonal cells with granular, eosinophilic cytoplasm which contains abundant lysosomes. It was originally thought to be a tumor originating from muscle cells and was named granular cell myoblastoma. Subsequent studies have suggested a derivation from schwann cells. It affects females more often than males and it usually presents as a solitary mass. A minority of patients have multiple tumors. It can arise from many anatomic sites including the posterior pituitary gland, skin, oral cavity, esophagus, stomach, heart, mediastinum, and breast.
• granulocytic sarcoma - a tumor mass composed of myeloblasts, neutrophils and neutrophil precursors. Granulocytic sarcoma is the most common type of myeloid sarcoma. (who, 2001)
• growth hormone-producing pituitary gland carcinoma - a rare, hormonally functioning or non-functioning pituitary gland adenocarcinoma that produces growth hormone. It may be associated with acromegaly.
• her2 positive breast carcinoma - a biologic subset of breast carcinoma defined by high expression of her2, grb7, and trap100, and by lack of expression of estrogen receptor (er).
• hairy cell leukemia - a neoplasm of small b-lymphocytes with "Hairy" projections in bone marrow, spleen, and peripheral blood. Most patients present with splenomegaly and pancytopenia. (who, 2001)
• hairy cell leukemia variant - an indolent chronic b-cell leukemia resembling classic hairy cell leukemia but shows variant cytologic, hematologic, and immunophenotypic features and is resistant to the conventional therapy applied to hairy cell leukemia. Biologically, it is not related to hairy cell leukemia.
• halo nevus - a melanocytic nevus characterized by circumferential depigmentation. It is usually associated with a brisk lymphocytic infiltrate.
• hand-schuller-christian disease - a multifocal, unisystem form of langerhans-cell histiocytosis. There is involvement of multiple sites in one organ system, most frequently the bone. Patients are usually young children presenting with multiple destructive bone lesions.
• head and neck carcinoma - a carcinoma that arises from the head and neck region. Representative examples include oral cavity squamous cell carcinoma, laryngeal squamous cell carcinoma, and salivary gland carcinoma.
• head and neck squamous cell carcinoma - a squamous cell carcinoma that arises from any of the following anatomic sites: lip and oral cavity, nasal cavity, paranasal sinuses, pharynx, larynx, and salivary glands.
• heavy chain disease - a group of rare disorders of immunoglobulin synthesis associated with b-cell proliferative disorders.
• helicobacter pylori-associated gastric mucosa-associated lymphoid tissue lymphoma - a low grade, indolent b-cell lymphoma that is associated with helicobacter pylori infection.
• helicobacter pylori-related gastric adenocarcinoma - an adenocarcinoma that arises from the gastric mucosa and is caused by persistent infection with helicobacter pylori.
• hemangioblastoma - a who grade I tumor of uncertain histogenesis which is composed of stromal cells and abundant capillaries. Approximately 25% of hemangioblastomas are associated with von hippel-lindau disease, a disease inherited through an autosomal dominant trait and characterized by the development of hemangioblastomas of the central nervous system and retina, clear cell renal carcinoma, pheochromocytoma, and pancreatic and inner ear tumors. (adapted from who)
• hemangioendothelioma - a vascular proliferation characterized by the presence of prominent endothelial cells and the formation of vascular channels. Hemangioendotheliomas may display borderline or low grade characteristics.
• hemangioma - a benign vascular lesion characterized by the formation of capillary-sized or cavernous vascular channels.
• hepatitis virus-related hepatocellular carcinoma - a hepatocellular carcinoma that develops following hepatitis virus exposure and injury of the liver parenchyma.
• hepatoblastoma - a malignant liver neoplasm that occurs almost exclusively in infants, although isolated cases in older children and adults have been reported. Grossly, hepatoblastoma is solid, well circumscribed, and more often solitary than multiple. Microscopically, most of the tumors are composed exclusively of immature hepatocytic elements. About a fourth of hepatoblastomas contain a stromal component that may be undifferentiated or develop into bone or cartilage. The treatment of choice for hepatoblastoma is surgical excision with adjuvant therapy. Liver transplantation is being increasingly used as well.
• hepatocellular adenoma - a benign epithelial neoplasm arising from the hepatocytes. Grossly, it appears as a soft, round mass which often contains areas of hemorrhage and necrosis. Morphologically, the neoplastic cells resemble normal hepatocytes and form plates separated by sinusoids. Most patients have a history of contraceptive or anabolic steroids use.
• hepatocellular carcinoma - a malignant tumor that arises from hepatocytes. Hepatocellular carcinoma is relatively rare in the united states but very common in all african countries south of the sahara and in southeast asia. Most cases are seen in patients over the age of 50 years, but this tumor can also occur in younger individuals and even in children. Hepatocellular carcinoma is more common in males than females and is associated with hepatitis b, hepatitis c, chronic alcohol abuse and cirrhosis. Serum elevation of alpha-fetoprotein occurs in a large percentage of patients with hepatocellular carcinoma. Grossly, hepatocellular carcinoma may present as a single mass, as multiple nodules, or as diffuse liver involvement. Microscopically, there is a wide range of differentiation from tumor to tumor (well differentiated to poorly differentiated tumors). Hepatocellular carcinomas quickly metastasize to regional lymph nodes and lung. The overall median survival of untreated liver cell carcinoma is about 4 months. The most effective treatment of hepatocellular carcinoma is complete resection of the tumor. Lately, an increasing number of tumors have been treated with liver transplantation.
• hepatosplenic t-cell lymphoma - an extranodal, mature t-cell non-hodgkin lymphoma that originates from cytotoxic t-cells, usually of gamma/delta t-cell type. It is characterized by the presence of medium-size neoplastic lymphocytes infiltrating the hepatic sinusoids. A similar infiltrating pattern is also present in the spleen and bone marrow that are usually involved at the time of the diagnosis.
• hereditary breast carcinoma - breast carcinoma that has developed in relatives of patients with history of breast carcinoma.
• hereditary clear cell renal cell carcinoma - hereditary clear cell renal cell carcinoma associated with biallelic loss/inactivation of the von hippel-lindau tumor suppressor gene.
• hereditary fallopian tube carcinoma - fallopian tube carcinoma that has developed in relatives of patients that have a history of fallopian tube carcinoma.
• hereditary gastric diffuse adenocarcinoma - an autosomal dominant inherited adenocarcinoma that arises from the gastric mucosa and is characterized by the presence of poorly cohesive malignant cells and absence of glandular formations.
• hereditary kidney wilms tumor - familial embryonal neoplasm derived from nephrogenic blastemal cells. Several lines of differentiation, including blastemal, stromal and epithelial, are usually expressed. Comprises approximately 1% of wilms tumors. (afip fascicle version 2.0)
• hereditary ovarian carcinoma - ovarian carcinoma that has developed in relatives of patients that have a history of ovarian carcinoma.
• hereditary pancreatic carcinoma - a carcinoma that arises from the pancreas in a patient with a family history of pancreatic cancer. In the minority of cases, patients have recognized genetic syndromes (e.G., fammm syndrome, brca2 syndrome, peutz-jeghers syndrome) however, in the majority of cases the genetic cause has not been identified.
• hereditary papillary renal cell carcinoma - a familial carcinoma inherited in an autosomal dominant trait. It is characterized by the development of multiple, bilateral papillary renal cell carcinomas. The carcinomas range from microscopic lesions to clinically symptomatic tumors. It is associated with activating mutations of the met oncogene.
• hereditary prostate carcinoma - prostate carcinoma that has developed in relatives of patients with a history of prostate carcinoma.
• hereditary retinoblastoma - an inherited malignant tumor that originates in the nuclear layer of the retina. A predisposition to retinoblastoma has been associated with 13q14 cytogenetic abnormalities. Patients with the inherited form appear to be at increased risk for secondary nonocular malignancies such as osteosarcoma, malignant fibrous histiocytoma, and fibrosarcoma.
• hereditary thyroid gland medullary carcinoma - a medullary thyroid gland carcinoma inherited through an autosomal dominant mode. It is associated with multiple endocrine neoplasia type ii (2a) or iii (2b).
• hidradenocarcinoma - a carcinoma with apocrine and less often eccrine differentiation, arising from the sweat glands. It usually presents as a solitary slow growing nodule in the dermis or subcutaneous tissues. It is characterized by a nodular growth pattern and it is often associated with necrotic changes.
• hidradenoma - a benign epithelial neoplasm arising from the sweat glands. Variants include the clear cell and nodular hidradenoma.
• hidrocystoma - a benign cystic proliferation of the sweat glands with apocrine or eccrine differentiation. It usually presents as a dome-shaped, cystic papular or nodular lesion usually in the face and neck. It is a unilocular or mutlilocular lesion lined by an inner and an outer layer of epithelium. Complete excision is usually curative.
• high grade astrocytic tumor - an anaplastic astrocytoma (grade iii astrocytic tumor) or glioblastoma (grade iv astrocytic tumor).
• high grade b-cell lymphoma with myc and bcl2 or bcl6 rearrangements - a rare b-cell non-hodgkin lymphoma that is characterized by the abnormal rearrangement of two genes, myc gene and either bcl2 or bcl6 genes. Patients with this type of lymphoma usually respond poorly to standard treatments and have a poor prognosis.
• high grade b-cell lymphoma, not otherwise specified - a high grade b-cell lymphoma with blastoid features or features between diffuse large b-cell lymphoma and burkitt lymphoma which lacks myc, bcl2, and bcl6 rearrangements.
• high grade ovarian serous adenocarcinoma - a rapidly growing serous adenocarcinoma that arises from the ovary. It is characterized by the presence of high grade cytologic features and frequent mitotic figures.
• hilar cholangiocarcinoma - a carcinoma that arises from the junction, or adjacent to the junction, of the right and left hepatic ducts.
• histiocytic sarcoma - an aggressive malignant neoplasm with a poor response to therapy, usually presenting as stage iii/iv disease. It is characterized by the presence of neoplastic cells with morphologic and immunophenotypic characteristics similar to those seen in mature histiocytes.
• histiocytic and dendritic cell neoplasm - rare tumors that affect the hematopoietic and lymphoid tissues. The cells of origin are the histiocytes and accessory cells. They can occur at any age and show no significant variations in geographical distribution. This category includes the histiocytic sarcoma, langerhans cell histiocytosis, langerhans cell sarcoma, interdigitading dendritic cell sarcoma/tumor, follicular dendritic cell sarcoma/tumor, and dendritic cell sarcoma, not otherwise specified. (who, 2001)
• hodgkin lymphoma - a lymphoma, previously known as hodgkin's disease, characterized by the presence of large tumor cells in an abundant admixture of nonneoplastic cells. There are two distinct subtypes: nodular lymphocyte predominant hodgkin lymphoma and classical hodgkin lymphoma. Hodgkin lymphoma involves primarily lymph nodes.
• human papillomavirus-related adenocarcinoma - an adenocarcinoma strongly associated with human papillomavirus infection.
• human papillomavirus-related cervical squamous cell carcinoma - a cervical squamous cell carcinoma associated with human papilloma virus infection. Histologic variants include papillary carcinoma, warty carcinoma, and squamotransitional carcinoma.
• human papillomavirus-related vulvar squamous cell carcinoma - a squamous cell carcinoma that arises from the vulva and is caused by human papillomavirus infection.
• hybrid nerve sheath tumor - a benign nerve sheath tumor characterized by the combination of histologic features seen in schwannomas, neurofibromas, and perineuriomas.
• hydroa vacciniforme-like lymphoproliferative disorder - a rare, ebv-positive cutaneous t-cell lymphoproliferative disorder, composed of cd8 positive cytotoxic t-lymphocytes. It affects children, almost exclusively in latin america and asia. Patients present with papulovesicular skin lesions, clinically resembling hydroa vacciniforme, in areas of sun-exposed skin.
• hyperdiploid b acute lymphoblastic leukemia - a b-cell acute leukemia characterized by the presence of lymphoblasts which contain more than 50 and usually less than 66 chromosomes. It is commonly seen in children and rarely in adults. It has a favorable clinical outcome.
• hypocellular myelodysplastic syndrome - myelodysplastic syndrome characterized by decreased cellularity in the bone marrow.
• hypodiploid b acute lymphoblastic leukemia - a b-cell acute leukemia characterized by the presence of lymphoblasts which contain less than 46 chromosomes. It occurs in both children and adults. It has an unfavorable clinical outcome.
• hypopharyngeal squamous cell carcinoma - a squamous cell carcinoma arising from the hypopharynx. Signs and symptoms include dysphagia, hemoptysis, and the presence of a neck mass.
• immature teratoma - a teratoma characterized by the presence of an extensive component of immature, fetal-type tissues.
• immunoblastic lymphoma - a diffuse large b-cell lymphoma characterized by the presence of immunoblasts with uniformly round-to-oval nuclei, a prominent nucleolus, and abundant cytoplasm.
• indeterminate dendritic cell tumor - a very rare dendritic cell tumor composed of spindle to ovoid cells with a phenotype that is similar to the langerhans cells. Patients usually present with cutaneous papules, nodules, and plaques. Systemic symptoms are usually absent. The clinical course is variable.
• infant acute lymphoblastic leukemia with mll rearrangement - an acute lymphoblastic leukemia with rearrangement of the mll (kmt2a) gene that occurs in infancy.
• infant acute lymphoblastic leukemia without mll gene rearrangement - an acute lymphoblastic leukemia without rearrangement of the mll (kmt2a) gene that occurs in infancy.
• infant leukemia - an acute lymphoblastic or acute myeloid leukemia that occurs in infancy.
• infantile fibrosarcoma - a fibrosarcoma that occurs in infants. It shares identical morphologic features with adult fibrosarcoma but carries the t(12;15)(p13;q25) translocation that results in etv6-ntrk3 gene fusion. It usually affects the superficial and deep soft tissues of the extremities. The prognosis is generally much more favorable than for adult fibrosarcoma, and it rarely metastasizes.
• infiltrating bladder urothelial carcinoma - an invasive transitional cell carcinoma that arises from the urinary bladder urothelium.
• infiltrating cervical carcinoma - a carcinoma that arises from the cervix and invades into the stromal tissue.
• infiltrating renal pelvis urothelial carcinoma, sarcomatoid variant - an infiltrating transitional cell carcinoma that arises from the renal pelvis and exhibits sarcomatoid features.
• inflammatory leiomyosarcoma - a morphologic variant of leiomyosarcoma characterized by the presence of an inflammatory infiltrate admixed with malignant spindle cells.
• inflammatory myofibroblastic tumor - a multinodular intermediate fibroblastic neoplasm that arises from soft tissue or viscera, in children and young adults. It is characterized by the presence of spindle-shaped fibroblasts and myofibroblasts, and a chronic inflammatory infiltrate composed of eosinophils, lymphocytes, and plasma cells.
• interdigitating dendritic cell sarcoma - a neoplastic proliferation of spindle to ovoid cells which show phenotypic features similar to those of interdigitating dendritic cells. The clinical course is generally aggressive. (who, 2008)
• intestinal follicular lymphoma - a follicular lymphoma arising from the intestine. The majority of cases occur in the small intestine, particularly the duodenum. Usually the patients have localized disease and a favorable clinical outcome.
• intestinal-type adenocarcinoma - an adenocarcinoma arising from epithelium which has undergone intestinal metaplasia. Representative examples include gastric, gallbladder, and ampulla of vater intestinal type adenocarcinomas.
• intrahepatic bile duct mucinous cystic neoplasm with an associated invasive carcinoma - a mucinous cystic neoplasm that arises from the intrahepatic bile ducts and it is associated with an invasive carcinomatous component.
• intrahepatic cholangiocarcinoma - a carcinoma that arises from the intrahepatic bile duct epithelium in any site of the intrahepatic biliary tree. Grossly, the malignant lesions are solid, nodular, and grayish. Morphologically, the vast majority of cases are adenocarcinomas. Signs and symptoms include malaise, weight loss, right upper quadrant abdominal pain, and night sweats. Early detection is difficult and the prognosis is generally poor.
• intramucosal adenocarcinoma - a neoplastic lesion that shows morphologic evidence of invasion into the lamina propria or muscularis mucosa. There is no evidence of invasion into the submucosa. Evidence of invasion may refer to stromal invasion by single cells or clusters of cells, presence of atypical and complex glandular architectural patterns beyond those that are present in normal mucosa, desmoplasia, and/or vascular invasion.
• intraocular retinoblastoma - retinoblastoma restricted to local involvement.
• intravascular large b-cell lymphoma - a rare extranodal b-cell non-hodgkin lymphoma, characterized by the presence of lymphoma cells exclusively in the lumina of small vessels, particularly capillaries. This is an extremely aggressive lymphoma which responds poorly to chemotherapy. (who, 2001)
• invasive breast carcinoma of no special type - the most common type of invasive breast carcinoma, accounting for approximately 70% of breast carcinomas. The gross appearance is usually typical with an irregular stellate outline. Microscopically, randomly arranged epithelial elements are seen. When large sheets of malignant cells are present, necrosis may be seen. With adequate tissue sampling, in situ carcinoma can be demonstrated in association with the infiltrating carcinoma. The in situ component is nearly always ductal but occasionally may be lobular or both.
• invasive breast lobular carcinoma - an infiltrating lobular adenocarcinoma of the breast. The malignant cells lack cohesion and are arranged individually or in a linear manner (indian files), or as narrow trabeculae within the stroma. The malignant cells are usually smaller than those of ductal carcinoma, are less pleomorphic, and have fewer mitotic figures.
• invasive breast papillary carcinoma - a ductal breast carcinoma which invades the breast parenchyma. It is characterized by the formation of papillary structures.
• invasive carcinoma - a carcinoma that is not confined to the epithelium, and has spread to the surrounding stroma.
• invasive malignant thymoma - a malignant thymoma that extends beyond the capsule and infiltrates the surrounding tissues.
• junctional nevus - a nevus characterized by the presence of an intraepidermal proliferation of nevus cells. The nevus cells form multiple nests in the dermal-epidermal junction. It presents as a small, slightly raised, pigmented skin lesion.
• juvenile myelomonocytic leukemia - a myelodysplastic/myeloproliferative neoplasm of childhood that is characterized by proliferation principally of the granulocytic and monocytic lineages. Myelomonocytic proliferation is seen in the bone marrow and the blood. The leukemic cells may infiltrate any tissue, however liver, spleen, lymph nodes, skin, and respiratory tract are the most common sites of involvement. (who, 2001)
• kaposi sarcoma - a malignant neoplasm characterized by a vascular proliferation which usually contains blunt endothelial cells. Erythrocyte extravasation and hemosiderin deposition are frequently present. The most frequent site of involvement is the skin; however it may also occur internally. It generally develops in people with compromised immune systems including those with acquired immune deficiency syndrome (aids).
• kaposiform hemangioendothelioma - an intermediate, locally aggressive blood vessel neoplasm characterized by the presence of spindle endothelial cells, and formation of capillary-sized and slit-like vascular channels. It is often associated with hemorrhage and hemosiderin deposition.
• keratoacanthoma - a dome-shaped, rapidly growing skin lesion composed of well differentiated squamous cells. It represents a proliferation of the infundibular epithelium of the hair follicle and its morphologic distinction from a well differentiated carcinoma may be difficult or impossible. Keratoacanthomas affect males more frequently than females and the majority tend to regress spontaneously. It has been suggested that keratoacanthoma represents a distinct subtype of squamous cell carcinoma of the skin.
• kidney carcinoma - a carcinoma arising from the epithelium of the renal parenchyma or the renal pelvis. The majority are renal cell carcinomas. Kidney carcinomas usually affect middle aged and elderly adults. Hematuria, abdominal pain, and a palpable mass are common symptoms.
• kidney medullary carcinoma - a type of renal carcinoma affecting mostly young african-americans. It is located in the medulla of the kidney, and follows an aggressive clinical course. Most reported cases have shown metastatic disease at the time of diagnosis.
• kidney oncocytoma - a benign tumor of the kidney, characterized by the presence of large cells with abundant eosinophilic granular cytoplasm. The majority of these tumors are discovered incidentally, during work-up of other conditions.
• kidney wilms tumor - an embryonal pediatric tumor of the kidney which may also be seen rarely in adults. The peak incidence of wilms tumor is between the second and fifth year of life. Microscopically, it is composed of a mixture of cellular elements (blastemal, stromal, and epithelial). The most common sites of metastasis include the regional lymph nodes, lungs, and liver.
• lh-producing gonadotroph adenoma - an adenoma of the anterior lobe of the pituitary gland that produces luteinizing hormone (lh).
• labia majora carcinoma - a carcinoma that arises from the labia majora.
• labia minora carcinoma - a carcinoma that arises from the labia minora.
• lacrimal gland carcinoma - a carcinoma that arises from the lacrimal glands. Representative examples include adenocarcinoma, carcinoma ex pleomorphic adenoma, squamous cell carcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma.
• lacrimal gland carcinoma ex pleomorphic adenoma - a carcinoma arising in a pre-existing pleomorphic adenoma in the lacrimal gland.
• lacrimal gland pleomorphic adenoma - a benign, usually encapsulated neoplasm of the lacrimal gland composed of epithelial and mesenchymal cells. Pleomorphic adenomas are neoplasms that develop in the salivary glands or heterotopic salivary gland tissues. It has been suggested that myoepithelial cells play a major role in the histogenesis of these tumors. In the lacrimal gland, pleomorphic adenomas presumably develop from metaplastic myoepithelial cells.
• lactating adenoma - a tubular type adenoma of the breast in which, during pregnancy and lactation, the epithelial cells show extensive secretory changes.
• lactotroph adenoma - an adenoma of the anterior lobe of the pituitary gland that produces prolactin. It is the most common type of pituitary gland adenomas and it is associated with hyperprolactinemia. Clinical manifestations include amenorrhea, galactorrhea, impotence, headache, and visual disturbances.
• langerhans cell histiocytosis - a neoplastic proliferation of langerhans cells which contain birbeck granules by ultrastructural examination. Three major overlapping syndromes are recognized: eosinophilic granuloma, letterer-siwe disease, and hand-schuller-christian disease. The clinical course is generally related to the number of organs affected at presentation. (who, 2001)
• langerhans cell sarcoma - a neoplastic proliferation of langerhans cells with overtly malignant cytologic features. It can be considered a higher grade variant of langerhans cell histiocytosis (lch) and it can present de novo or progress from antecedent lch. (who, 2001)
• large cell carcinoma - a malignant epithelial neoplasm composed of large, atypical cells.
• large cell medulloblastoma - a medulloblastoma composed of large cells with prominent nucleoli and a larger amount of cytoplasm in contrast with the cells of the classic medulloblastoma.
• large cell neuroendocrine carcinoma - a usually aggressive carcinoma composed of large malignant cells which display neuroendocrine characteristics. It is characterized by the presence of high mitotic activity and necrotic changes. The vast majority of cases are positive for neuron-specific enolase. Representative examples include lung, breast, cervical, and thymic neuroendocrine carcinomas.
• large cell/anaplastic medulloblastoma - a medulloblastoma composed of sheets of large cells mixed with cells characterized by marked nuclear pleomorphism and high mitotic activity.
• laryngeal squamous cell carcinoma - a squamous cell carcinoma that arises from the larynx. It is the most common histologic type of laryngeal carcinoma. It can arise from the glottis, supraglottic area, or it can be transglottic. Glottic squamous cell carcinoma is the most frequent laryngeal carcinoma in the united states. The symptoms, clinical behavior and the prognosis depend on the site of origin within the larynx.
• leiomyoma - a well-circumscribed benign smooth muscle neoplasm characterized by the presence of spindle cells with cigar-shaped nuclei, interlacing fascicles, and a whorled pattern.
• leiomyosarcoma - an uncommon, aggressive malignant smooth muscle neoplasm, usually occurring in post-menopausal women. It is characterized by a proliferation of neoplastic spindle cells. Morphologic variants include epithelioid, granular cell, inflammatory and myxoid leimyosarcomas.
• lentigo maligna melanoma - a melanoma of the skin characterized by single cell infiltration of the papillary dermis by atypical melanocytes, in a background of lentigo maligna changes.
• lepidic predominant adenocarcinoma - a lung adenocarcinoma characterized by the presence of mildly and moderately differentiated adenocarcinoma cells across the alveolar walls with at least one focus of invasive carcinoma measuring more than 5 mm in greatest dimension.
• letterer-siwe disease - a multifocal, multisystem form of langerhans-cell histiocytosis. There is involvement of multiple organ systems including the bones, skin, liver, spleen, and lymph nodes. Patients are usually infants presenting with fever, hepatosplenomegaly, lymphadenopathy, bone and skin lesions, and pancytopenia.
• leukemia - a malignant (clonal) hematologic disorder, involving hematopoietic stem cells and characterized by the presence of primitive or atypical myeloid or lymphoid cells in the bone marrow and the blood. Leukemias are classified as acute or chronic based on the degree of cellular differentiation and the predominant cell type present. Leukemia is usually associated with anemia, fever, hemorrhagic episodes, and splenomegaly. Common leukemias include acute myeloid leukemia, chronic myelogenous leukemia, acute lymphoblastic or precursor lymphoblastic leukemia, and chronic lymphocytic leukemia. Treatment is vital to patient survival; untreated, the natural course of acute leukemias is normally measured in weeks or months, while that of chronic leukemias is more often measured in months or years.
• lip basal cell carcinoma - a basal cell carcinoma arising from the lip.
• lip carcinoma - a malignant epithelial neoplasm arising from the lips.
• lip squamous cell carcinoma - a squamous cell carcinoma that arises from the lip. It affects males more often than females and it usually involves the lower lip. Risk factors include uv exposure, alcohol consumption, smoking, and immunosuppression.
• lip and oral cavity carcinoma - a carcinoma arising in the lip or oral cavity. Most oral cavity carcinomas are squamous cell carcinomas of the tongue, buccal mucosa, or gums. Less frequent morphologic variants include mucoepidermoid carcinoma and adenocarcinoma. Lip carcinomas are usually basal cell or squamous cell carcinomas.
• lip and oral cavity squamous cell carcinoma - a squamous cell carcinoma arising from the lip or the oral cavity. The oral cavity squamous cell carcinoma usually arises from the buccal mucosa, tongue, or gums. It occurs predominantly in adults who use tobacco and alcohol and has a tendency to metastasize early to lymph nodes.
• lipoblastoma - a lipoma usually occurring in the extremities of young children (usually boys). It is characterized by lobules of adipose tissue, separated by fibrous septa. The adipose tissue is composed of mature adipocytes and lipoblasts. The lipoblasts may be scarce, depending on the age of the patient.
• lipoma - a benign, usually painless, well-circumscribed lipomatous tumor composed of adipose tissue.
• lipomatosis - a neoplastic process characterized by diffuse overgrowth of mature adipose tissue.
• liposarcoma - a usually painless malignant tumor that arises from adipose tissue. Microscopically, it may contain a spectrum of neoplastic adipocytes ranging from lipoblasts to pleomorphic malignant adipocytes. Morphologic variants include: well differentiated, dedifferentiated, pleomorphic, and myxoid liposarcoma. The metastatic potential is higher in less differentiated tumors.
• liver carcinosarcoma - an aggressive carcinoma with a sarcomatous component that arises from the liver. The sarcomatous component is clonally related to the more differentiated, carcinomatous component. The prognosis is usually poor.
• liver and intrahepatic bile duct carcinoma - a carcinoma that arises from the hepatocytes or intrahepatic bile ducts. The main subtypes are hepatocellular carcinoma (hepatoma) and cholangiocarcinoma.
• low grade appendix mucinous neoplasm - a well differentiated mucinous neoplasm that arises from the appendix. It is characterized by slow growth and it is associated with the development of pseudomyxoma peritonei.
• low grade astrocytic tumor - a grade I or grade ii astrocytic tumor. This category includes pilocytic astrocytoma (grade I), subependymal giant cell astrocytoma (grade I), and diffuse astrocytoma (grade ii).
• low grade endometrioid stromal sarcoma - an infiltrating mesenchymal tumor arising from the uterine corpus, cervix, vagina, and the ovary. It is characterized by the presence of oval to spindle-shape cells that resemble the cells of the endometrial stroma, without evidence of significant atypia and pleomorphism. Numerous small vessels are also present. It is usually characterized by indolent growth and late recurrences.
• low grade ovarian serous adenocarcinoma - a slow-growing serous adenocarcinoma that arises from the ovary. It usually originates from borderline neoplastic processes or adenofibromas. It is characterized by the presence of low grade cytologic features and infrequent mitotic figures.
• low-csd melanoma - a type of melanoma that typically occurs in light-skinned individuals ranging in age from young adults to the elderly. Risk factors include extensive sun exposure during childhood, a family history of melanoma, and the presence of dysplastic nevi.
• lower gingival squamous cell carcinoma - a squamous cell carcinoma of the oral cavity that arises from the lower gingiva.
• luminal a breast carcinoma - a biologic subset of breast carcinoma defined by high expression of genes characteristic of luminal epithelial cells, including estrogen receptor (er), estrogen regulated protein liv-1, and the transcription factors hepatocyte nuclear factor 3, hnf3a, xbp1, and gata 3. This subtype of breast cancer is associated with a good prognosis.
• luminal b breast carcinoma - a biologic subset of breast carcinoma defined by low to moderate expression of genes characteristic of luminal epithelial cells including estrogen receptor (er), and high expression of ggh, laptm4b, and ccne1. This subtype of breast cancer is associated with a good prognosis, although not as favorable as the luminal a subtype.
• lung acinar adenocarcinoma - a morphologic variant of lung adenocarcinoma characterized by the presence of acinar structures composed of columnar or cuboidal cells. (nci05)
• lung adenocarcinoma - a carcinoma that arises from the lung and is characterized by the presence of malignant glandular epithelial cells. There is a male predilection with a male to female ratio of 2:1. Usually lung adenocarcinoma is asymptomatic and is identified through screening studies or as an incidental radiologic finding. If clinical symptoms are present they include shortness of breath, cough, hemoptysis, chest pain, and fever. Tobacco smoke is a known risk factor.
• lung adenoid cystic carcinoma - a rare usually indolent lung carcinoma characterized by a cribiform and tubular pattern and the presence of glandular epithelial cells. Clinical symptoms include shortness of breath, cough, wheeze, hemopytsis and chest pain.
• lung adenosquamous carcinoma - an aggressive carcinoma with a poor prognosis characterized by a presence of both malignant squamous cells and glandular cells.
• lung basaloid large cell carcinoma - a large cell lung carcinoma characterized by the presence of a solid nodular or anastomotic trabecular growth pattern, peripheral palisading, and comedo type necrosis.
• lung basaloid squamous cell carcinoma - a morphologic variant of squamous cell lung carcinoma characterized by nuclear palisading.
• lung carcinoma - a carcinoma originating in the lung. Lung carcinomas usually arise from the epithelium that lines the bronchial tree (bronchogenic carcinomas), and are classified as small cell or non-small cell carcinomas. Non-small cell lung carcinomas are usually adenocarcinomas, squamous cell carcinomas, or large cell carcinomas. Metastatic carcinomas to the lung are also common, and can be difficult to distinguish from primary tumors.
• lung carcinosarcoma - a morphologic variant of lung sarcomatoid carcinoma composed of a mixture of non-small cell lung carcinoma and a sarcomatous component.
• lung colloid adenocarcinoma - a morphologic variant of lung adenocarcinoma characterized by the presence of mucin pools containing islands of well differentiated adenocarcinoma cells.
• lung epithelial-myoepithelial carcinoma - a lung carcinoma arising within the bronchi or bronchial tubes. It is characterized by the presence of myoepithelial cells, spindle cells, clear cells, and duct-forming epithelial cells. Surgical resection may be curative.
• lung fetal adenocarcinoma - a rare morphologic variant of lung adenocarcinoma characterized by the presence of glandular structures containing glycogen-rich cells forming tubules that resemble fetal lung tubules.
• lung giant cell carcinoma - a morphologic variant of lung sarcomatoid carcinoma characterized by the presence of mononuclear and multinucleated pleomorphic neoplastic giant cells that lack cohesion.
• lung large cell carcinoma - an undifferentiated non-small cell lung carcinoma composed of large polygonal cells without evidence of glandular, squamous, or neuroendocrine differentiation.
• lung large cell carcinoma with rhabdoid phenotype - a large cell lung carcinoma characterized by the presence of rhabdoid cells.
• lung large cell carcinoma, clear cell variant - a large cell lung carcinoma characterized by a predominance of clear cells that may or may not contain glycogen.
• lung large cell neuroendocrine carcinoma - a high grade malignant neoplasm that arises from the lung and is characterized by the presence of large neuroendocrine cells. It usually has an aggressive clinical course.
• lung lymphoepithelioma-like carcinoma - a rare and distinctive type of lung carcinoma characterized by the presence of a syncytial growth pattern, large vesicular nuclei with eosinophilic nucleoli, and dense lymphoplasmacytic infiltration.
• lung mucinous cystadenoma - a very rare, well circumscribed, benign cystic neoplasm that arises from the lung. It is characterized by the presence of cysts which are lined by tall mucinous epithelium and filled with mucin.
• lung mucoepidermoid carcinoma - a lung carcinoma characterized by the presence of malignant non-keratinizing squamoid cells, mucin-producing cells and intermediate type cells.
• lung mucous gland adenoma - a benign adenomatous neoplasm that arises from the mucous glands in the bronchus.
• lung non-small cell carcinoma - a group of at least three distinct histological types of lung cancer, including non-small cell squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. Non-small cell lung carcinomas have a poor response to conventional chemotherapy.
• lung papillary adenocarcinoma - a morphologic variant of lung adenocarcinoma characterized by the presence of papillary structures.
• lung papillary adenoma - a benign lung neoplasm characterized by the presence of a fibrovascular stroma lined by cuboidal to columnar cells. Patients are usually asymptomatic and it is incidentally discovered as a pulmonary nodule during chest x-ray examination. Surgical excision is curative.
• lung pleomorphic adenoma - a very rare, well circumscribed, benign epithelial neoplasm that arises from the bronchus. It is characterized by the presence of epithelial cells, myoepithelial cells, and fibromyxoid stroma.
• lung pleomorphic carcinoma - a morphologic variant of sarcomatoid carcinoma characterized by the presence of malignant glandular or squamous cells associated with malignant giant and spindle cells.
• lung sarcomatoid carcinoma - a rare, aggressive, poorly differentiated, non-small cell lung carcinoma characterized by the presence of a sarcomatoid component often associated with giant cell differentiation. There is a male to female ratio of 4:1. Clinical symptoms include cough, hemoptysis, chest pain, progressive dyspnea and fever secondary to recurrent pneumonia. Cigarette smoking is a major risk factor.
• lung small cell carcinoma - a highly aggressive subtype of lung carcinoma characterized by the presence of malignant small cells and necrosis. Metastatic disease is usually present at the time of diagnosis.
• lung spindle cell carcinoma - a morphologic variant of sarcomatoid carcinoma characterized by the presence of malignant spindle cells and focal lymphoplasmacytic infiltrates. Adenocarcinoma cells, malignant squamous cells, and giant cells are not present.
• lung squamous cell carcinoma - a carcinoma arising from squamous bronchial epithelial cells. It may be keratinizing or non-keratinizing. Keratinizing squamous cell carcinoma is characterized by the presence of keratinization, pearl formation, and/or intercellular bridges. Non-keratinizing squamous cell carcinoma is characterized by the absence of keratinization, pearl formation, and intercellular bridges. Cigarette smoking and arsenic exposure are strongly associated with squamous cell lung carcinoma.
• lung squamous cell carcinoma, clear cell variant - a morphologic variant of squamous cell lung carcinoma characterized by the presence of clear cells.
• lung squamous cell carcinoma, papillary variant - a morphologic variant of squamous cell lung carcinoma characterized by the presence of papillary structures.
• lung squamous cell carcinoma, small cell variant - a poorly differentiated morphologic variant of squamous cell lung carcinoma characterized by the presence of small tumor cells with focal squamous differentiation.
• lymphangioma - a benign lesion composed of dilated lymphatic channels. Painless swelling is the usual clinical manifestation.
• lymphangiosarcoma - a malignant neoplasm arising from the endothelial cells of the lymphatic vessels.
• lymphoblastic lymphoma - a lymphoma composed of immature small to medium-sized precursor lymphoid cells (lymphoblasts). It includes the b- and t-cell lymphoblastic lymphoma.
• lymphocyte-depleted classic hodgkin lymphoma - a diffuse subtype of classic hodgkin lymphoma which is rich in hodgkin and reed-sternberg cells and/or depleted in non-neoplastic lymphocytes. (who, 2008)
• lymphocyte-rich classic hodgkin lymphoma - a subtype of classic hodgkin lymphoma with scattered hodgkin and reed-sternberg cells and a nodular or less often diffuse cellular background consisting of small lymphocytes and with an absence of neutrophils and eosinophils. (who, 2008)
• lymphoepithelioid variant peripheral t-cell lymphoma - a variant of peripheral t-cell lymphoma, not otherwise specified. It is characterized by the presence of neoplastic small lymphocytes infiltrating the lymph nodes in a diffuse and less frequently interfollicular pattern. There is an associated proliferation of epithelioid histiocytes forming confluent clusters.
• lymphoma - a malignant (clonal) proliferation of b- lymphocytes or t- lymphocytes which involves the lymph nodes, bone marrow and/or extranodal sites. This category includes non-hodgkin lymphomas and hodgkin lymphomas.
• lymphomatoid granulomatosis - an angiocentric and angiodestructive lymphoproliferative disease involving extranodal sites, comprised of epstein-barr virus (ebv)-positive b-cells admixed with reactive t-cells. Incidence is higher among adult males; patients with a history of immunodeficiency are at increased risk. The most common site of involvement is the lung; other common sites include brain, kidney, liver, and skin. Morphologically, three grades are recognized: grade I, ii, and iii. Grade iii lymphomatoid granulomatosis should be approached clinically as a subtype of diffuse large b-cell lymphoma.
• lymphomatoid papulosis - a chronic, recurrent cutaneous disorder characterized by the presence of spontaneously regressing papules. The papules are composed of an atypical lymphocytic infiltrate that contains anaplastic cd30-positive t-cells, which are found in type a and diffuse large cell type (type c) lymphomatoid papulosis. In a small number of cases, of type b, the lymphocytic infiltrate is composed of small, cerebriform-like lymphocytes that are often negative for cd30. The majority of cases follow a benign clinical course, but some cases are clonal and may progress to lymphoma. Treatment options include low dose methotrexate and psoralen/uva (puva).
• lymphoplasmacyte-rich meningioma - a who grade I meningioma characterized by the presence of prominent chronic inflammatory infiltrates that predominate over the meningioma cells.
• lymphoplasmacytic lymphoma - a clonal neoplasm of small b-lymphocytes, lymphoplasmacytoid cells, and plasma cells involving the bone marrow, lymph nodes, and the spleen. The majority of patients have a serum igm paraprotein.
• male breast carcinoma - a rare malignant tumor of the breast, affecting mostly older men. It accounts for less than 1% of all malignancies in men. The most common histologic type is invasive ductal carcinoma. Most patients are treated with mastectomy.
• malignant adrenal gland pheochromocytoma - a pheochromocytoma that metastasizes to other anatomic sites. Common sites of metastasis include lymph nodes, bones, liver, and lung. Morphologic features associated with malignant pheochromocytomas include: atypical mitotic figures, capsular and vascular invasion, tumor cell necrosis, and high mitotic activity.
• malignant breast phyllodes tumor - a phyllodes tumor of the breast characterized by infiltrative margins and a sarcomatous stromal component. The sarcomatous stroma usually displays features of fibrosarcoma. Liposarcomatous, osteosarcomatous, or rhabdomyosarcomatous elements may also be present.
• malignant extragonadal germ cell tumor - a malignant germ cell tumor that develops as a primary tumor in an anatomic site other than the testis or ovary.
• malignant gastrinoma - a gastrin-producing neuroendocrine tumor. It is characterized by inappropriate secretion of gastrin and associated with zollinger ellison syndrome. It displays vascular invasion and metastasizes to other anatomic sites.
• malignant gastrointestinal stromal tumor - a gastrointestinal stromal tumor that is characterized by large size (diameter greater than 10 cm for gastric localization and greater than 5 cm for intestinal localization) or more than 5 mitotic figures per 50 high power fields.
• malignant germ cell tumor - a gonadal or extragonadal malignant neoplasm that arises from germ cells. Representative examples include embryonal carcinoma, yolk sac tumor, and seminoma.
• malignant glioma - a grade iii or grade iv glioma arising from the central nervous system. This category includes glioblastoma, anaplastic astrocytoma, anaplastic ependymoma, anaplastic oligodendroglioma, and anaplastic oligoastrocytoma.
• malignant glomus tumor - a very rare morphologic variant of glomus tumor with a size greater than 2 cm. The tumor arises in subfascial or visceral tissues. It is characterized by the presence of atypical mitotic figures, or marked nuclear atypia, or the combination of both. It has an aggressive clinical course.
• malignant granular cell tumor - an uncommon granular cell tumor which may metastasize to other anatomic sites. Morphologic characteristics include the presence of spindling neoplastic cells, necrosis, extensive pleomorphism, prominent nucleoli, and increased mitiotic activity.
• malignant melanotic peripheral nerve sheath tumor - a rare variant of malignant peripheral nerve sheath tumor. It is characterized by the presence of malignant cells that contain melanin.
• malignant mesothelioma - a malignant neoplasm that arises from mesothelial cells. It is associated with exposure to asbestos.
• malignant mixed mesodermal (mullerian) tumor - an aggressive malignant tumor of the female reproductive system, affecting predominantly elderly menopausal women. The endometrium and ovary are the most common sites of tumor origin. Morphologically, it is a high grade tumor, composed of carcinomatous and sarcomatous elements.
• malignant osteoclastic giant cell-rich tumor of bone - a giant cell tumor that arises from the bone and is characterized by the presence of a malignant cellular component.
• malignant ovarian germ cell tumor - an invasive malignant neoplasm that arises from the ovary and originates from primordial germ cells. Representative examples include embryonal carcinoma, yolk sac tumor, dysgerminoma, and non-gestational choriocarcinoma.
• malignant peripheral nerve sheath tumor - an uncommon, highly aggressive malignant tumor, arising from the peripheral nerves and affecting mostly adults in their third to sixth decades of life. It usually occurs in medium-sized and large nerves of the buttock, thigh, upper arm, or the paraspinal region. It may be associated with neurofibromatosis 1 (nf1).
• malignant peripheral nerve sheath tumor with mesenchymal differentiation - a malignant peripheral nerve sheath tumor characterized by the presence of mesenchymal differentiation. Representative example is the malignant triton tumor which contains a rhabdomyosarcomatous component.
• malignant phyllodes tumor - a phyllodes tumor with sarcomatous stroma. The sarcomatous component is usually of the fibrosarcomatous type. Liposarcomatous, chondrosarcomatous, osteosarcomatous, or rhabdomyosarcomatous differentiation may also occur in the stroma. It may recur and metastasize following surgical resection. The lung and skeleton are the anatomic sites most frequently involved by metastases.
• malignant prostate phyllodes tumor - an unusual malignant tumor that arises from the prostate gland. It is characterized by the presence of glandular elements and a cellular stroma that exhibits mitotic activity and nuclear atypia.
• malignant solitary fibrous tumor - a malignant neoplasm of probable fibroblastic derivation. It is characterized by the presence of atypical round to spindle-shaped cells, increased cellularity, necrotic change and high mitotic activity.
• malignant somatostatinoma - a malignant neuroendocrine tumor arising from delta cells which produce somatostatin. It displays vascular invasion and metastasizes to other anatomic sites.
• malignant tenosynovial giant cell tumor - an uncommon malignant tumor arising from the tendon sheath. Morphologically, it is characterized by the presence of a cellular infiltrate reminiscent of a giant cell tumor with prominent malignant characteristics. Recurrent giant cell tumors with a sarcomatous dedifferentiation are included in this category as well.
• malignant testicular germ cell tumor - a malignant tumor predominantly affecting young men and often associated with cryptorchidism. Seminoma is the most frequently seen malignant testicular germ cell tumor, followed by embryonal carcinoma and yolk sac tumor.
• malignant thymoma - a thymoma that has an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize. Although any morphologic subtype of thymoma may eventually have a malignant clinical course, this term is most often associated with thymoma types b3 and c.
• malignant triton tumor - a malignant peripheral nerve sheath tumor which shows rhabdomyosarcomatous differentiation. More than half of the patients have neurofibromatosis type 1. The prognosis is usually poor.
• malignant type a thymoma - a type a thymoma which is characterized by an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize.
• malignant type ab thymoma - a type ab thymoma which is characterized by an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize.
• malignant type b1 thymoma - a type b1 thymoma which is characterized by an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize.
• malignant type b2 thymoma - a type b2 thymoma which is characterized by an aggressive clinical course (capsular invasion, infiltration of the surrounding tissues) and can metastasize.
• malignant vipoma - an aggressive neuroendocrine tumor located in the pancreas or small intestine. It is composed of cells containing vasoactive intestinal peptide. It is associated with watery diarrhea, hypokalemia, and hypochlorhydria or achlorhydria. It displays vascular invasion and metastasizes to other anatomic sites.
• mammosomatotroph adenoma - a pituitary gland adenoma composed of acidophilic cells that produce both growth hormone and prolactin. Immunohistochemical studies reveal the presence of these two hormones localized in the same cell.
• mantle cell lymphoma - an aggressive, usually diffuse non-hodgkin lymphoma composed of small to medium sized b-lymphocytes (centrocytes). Most patients present with advanced stage disease with lymphadenopathy, hepatosplenomegaly, and bone marrow involvement. The gastrointestinal tract is the most commonly affected extranodal site by this type of non-hodgkin lymphoma. The vast majority of cases express the t(11;14)(q13;q32) resulting in the rearrangement of the bcl-1 gene and the overexpression of cyclin d1 mrna.
• marginal zone lymphoma - a usually indolent mature b-cell lymphoma, arising from the marginal zone of lymphoid tissues. It is characterized by the presence of small to medium sized atypical lymphocytes. It comprises three entities, according to the anatomic sites involved: extranodal marginal zone b-cell lymphoma of mucosa-associated lymphoid tissue, which affects extranodal sites (most often stomach, lung, skin, and ocular adnexa); nodal marginal zone b-cell lymphoma, which affects lymph nodes without evidence of extranodal disease; and splenic marginal zone b-cell lymphoma, which affects the spleen and splenic hilar lymph nodes, bone marrow, and often the peripheral blood.
• mast cell leukemia - a variant of systemic mastocytosis with involvement of the bone marrow (20% or more mast cells) and the peripheral blood (mast cells account for 10% or more of peripheral blood white cells). (who, 2001)
• mast cell sarcoma - a rare malignant neoplasm characterized by localized but destructive growth of a tumor consisting of highly atypical, immature mast cells.(who, 2001)
• mature t-cell and nk-cell non-hodgkin lymphoma - this type of lymphoma is not frequently seen in the western hemisphere. Clinically, with the exception of anaplastic large cell lymphoma, mature t- and nk-cell lymphomas are among the most aggressive of all hematopoietic neoplasms. Representative disease entities include mycosis fungoides, angioimmunoblastic t-cell lymphoma, hepatosplenic t-cell lymphoma, and anaplastic large cell lymphoma.
• mature teratoma - a teratoma which may be cystic; it is composed entirely of well differentiated, adult-type mature tissues, without evidence of fetal-type immature tissues (grade 0 teratoma).
• medulloblastoma - a malignant, invasive embryonal neoplasm arising from the cerebellum or posterior fossa. It occurs predominantly in children and has the tendency to metastasize via the cerebrospinal fluid pathways. Signs and symptoms include truncal ataxia, disturbed gait, lethargy, headache, and vomiting. There are four histologic variants: classic medulloblastoma, large cell/anaplastic medulloblastoma, desmoplastic/nodular medulloblastoma, and medulloblastoma with extensive nodularity.
• medulloblastoma with extensive nodularity - a medulloblastoma characterized by nodularity and neuronal differentiation.
• medulloblastoma, non-wnt/non-shh - medulloblastoma not associated with activation of the wnt pathway or sonic hedgehog (shh) pathway. Tp53 mutations are absent. This molecular subtype includes medulloblastomas numerically designated as "Group 3" and "Group 4".
• medulloblastoma, shh-activated - a molecular subtype of medulloblastoma associated with activation of the sonic hedgehog (shh) pathway. Tp53 mutations may be present or absent. Patients in this group are young children and adults. Overall survival is variable and depends on the presence or absence of metastatic disease, histology, and the age at diagnosis.
• medulloblastoma, shh-activated, tp53-mutant - medulloblastoma associated with activation of the sonic hedgehog (shh) pathway and the presence of tp53 mutations.
• medulloblastoma, shh-activated, tp53-wildtype - medulloblastoma associated with activation of the sonic hedgehog (shh) pathway and the absence of tp53 mutations.
• medulloblastoma, wnt-activated - a molecular subtype of medulloblastoma associated with activation of the wnt pathway. Tp53 mutations may be present or absent. Wnt pathway activation in medulloblastomas is associated with good outcome.
• melanoma - a malignant, usually aggressive tumor composed of atypical, neoplastic melanocytes. Most often, melanomas arise in the skin (cutaneous melanomas) and include the following histologic subtypes: superficial spreading melanoma, nodular melanoma, acral lentiginous melanoma, and lentigo maligna melanoma. Cutaneous melanomas may arise from acquired or congenital melanocytic or dysplastic nevi. Melanomas may also arise in other anatomic sites including the gastrointestinal system, eye, urinary tract, and reproductive system. Melanomas frequently metastasize to lymph nodes, liver, lungs, and brain.
• melanotic psammomatous malignant peripheral nerve sheath tumor - a malignant peripheral nerve sheath tumor characterized by the presence of malignant cells that contain melanin and formation of psammoma bodies.
• meningeal solitary fibrous tumor/hemangiopericytoma - a solitary fibrous tumor/hemangiopericytoma that arises from the meninges.
• meningeal solitary fibrous tumor/hemangiopericytoma, grade 3 - a solitary fibrous tumor/hemangiopericytoma that arises from the meninges. It most often corresponds to the tumor previously diagnosed as anaplastic hemangiopericytoma.
• meningioma - a generally slow growing tumor attached to the dura mater. It is composed of neoplastic meningothelial (arachnoidal) cells. It typically occurs in adults, often women and it has a wide range of histopathological appearances. Of the various subtypes, meningothelial, fibrous and transitional meningiomas are the most common. Most meningiomas are who grade I tumors, and some are who grade ii or iii tumors. Most subtypes share a common clinical behavior, although some subtypes are more likely to recur and follow a more aggressive clinical course. (adapted from who)
• merkel cell carcinoma - a rare malignant cutaneous tumor seen in elderly patients. Its usual location is on the head, neck and extremities. The tumor is composed of small round cells with scanty cytoplasm arranged in a trabecular pattern, or in ill-defined nodules or in a diffuse pattern. The tumor cells contain cytoplasmic membrane-bound dense core granules resembling neurosecretory granules. There is strong evidence implicating merkel cell polyomavirus in a majority of cases of merkel cell carcinoma.
• mesenchymal chondrosarcoma - a morphologic variant of chondrosarcoma arising from bone and soft tissue. It is characterized by the presence of malignant small round cells, biphasic growth pattern, and well differentiated hyaline cartilage. Clinical presentation includes pain and swelling. The clinical course is aggressive, with local recurrences and distant metastases.
• mesenchymal glioblastoma - a molecular subtype of glioblastoma characterized by the presence of nf1 mutations.
• mesothelioma - a usually malignant and aggressive neoplasm of the mesothelium which is often associated with exposure to asbestos.
• metachronous kidney wilms tumor - wilms tumor arising in the remaining kidney following treatment of the original wilms tumor.
• metachronous osteosarcoma - a bone osteosarcoma that has metastasized to skeletal or extraskeletal sites.
• metaplastic meningioma - a who grade I meningioma characterized by the presence of a prominent mesenchymal component. The mesenchymal component may be osseous, cartilaginous, myxoid, lipomatous, or a mixture of mesenchymal elements.
• microcystic meningioma - a who grade I meningioma characterized by the presence of intercellular microcystic spaces that contain mucinous fluid.
• microgranular acute promyelocytic leukemia - acute promyelocytic leukemia in which the promyelocytes in the peripheral blood have paucity or absence of cytoplasmic granules and characteristic bilobed nuclei.
• middle ear carcinoma - a carcinoma that arises from the middle ear. This category includes adenocarcinoma and squamous cell carcinoma.
• minimally invasive lung adenocarcinoma - a solitary adenocarcinoma arising from the lung and measuring 3 cm or less in size. It is characterized by a predominantly lepidic pattern and 5 mm or less invasion in greatest dimension. It is usually a non-mucinous adenocarcinoma, but rarely may be mucinous.
• minor salivary gland adenocarcinoma - an adenocarcinoma that arises from the minor salivary glands.
• minor salivary gland adenoid cystic carcinoma - an aggressive carcinoma that arises from the minor salivary glands. It is characterized by the presence of malignant epithelial and myoepithelial cells forming cribriform, tubular, and solid patterns. It usually presents as a slow growing mass.
• minor salivary gland carcinoma - a carcinoma that arises from the minor salivary glands. Representative examples include adenoid cystic carcinoma, acinic cell carcinoma, polymorphous low grade adenocarcinoma, and mucinous adenocarcinoma.
• minor salivary gland carcinoma ex pleomorphic adenoma - a carcinoma that arises from a pleomorphic adenoma in the minor salivary glands. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.
• minor salivary gland mucoepidermoid carcinoma - a carcinoma that arises from the minor salivary glands. It usually presents as a firm and painless mass. It is characterized by the presence of epidermoid cells, mucus producing cells, and cells of intermediate type. The majority of cases have a favorable outcome.
• minor salivary gland small cell neuroendocrine carcinoma - an infrequent small cell carcinoma that arises from a minor salivary gland. It is characterized by the presence of neuroendocrine differentiation and a high number of mitotic figures.
• minor salivary gland squamous cell carcinoma - a squamous cell carcinoma that affects the minor salivary glands.
• minor salivary gland undifferentiated carcinoma - a carcinoma that affects the minor salivary glands and is characterized by the presence of undifferentiated, anaplastic malignant epithelial cells.
• mixed astrocytoma-ependymoma - a tumor of mixed cell type with astrocytic components as well as ependymoma components.
• mixed astrocytoma-ependymoma-oligodendroglioma - a mixed glioma characterized by the presence of astrocytic, ependymal, and oligodendroglial neoplastic components.
• mixed cell type kidney wilms tumor - wilms tumor of the kidney characterized by the presence of blastema, epithelial, and mesenchymal components (triphasic pattern) or a combination of two of them (biphasic pattern).
• mixed cellularity classic hodgkin lymphoma - a subtype of classic hodgkin lymphoma with scattered reed-sternberg and hodgkin cells in a diffuse or vaguely nodular mixed inflammatory background without nodular sclerosing fibrosis. (who, 2008)
• mixed congenital mesoblastic nephroma - a congenital mesoblastic nephroma characterized by the presence of classic and cellular areas.
• mixed epithelioid and spindle cell melanoma - a melanoma characterized by the presence of malignant large epithelioid melanocytes and malignant spindle-shaped melanocytes.
• mixed germ cell tumor - a malignant germ cell tumor characterized by the presence of at least two different germ cell tumor components. The different germ cell tumor components include choriocarcinoma, embryonal carcinoma, yolk sac tumor, teratoma, and seminoma. It occurs in the ovary, testis, and extragonadal sites including central nervous system and mediastinum.
• mixed germ cell-sex cord-stromal tumor - a biphasic neoplasm that arises from the ovary or the testis. It is characterized by the presence of neoplastic germ cells and neoplastic sex cord-stromal cells. It includes the gonadoblastoma and mixed germ cell-sex cord stromal tumor, unclassifiable.
• mixed glioma - a tumor composed of two or more glial cell types (astrocytes, ependymal cells, and oligodendrocytes).
• mixed liposarcoma - a malignant neoplasm characterized by the presence of a combination of liposarcomatous morphologic subtypes: myxoid/round cell and well differentiated/dedifferentiated liposarcoma or myxoid/round cell and pleomorphic liposarcoma.
• mixed phenotype acute leukemia - an acute leukemia of ambiguous lineage. It is characterized by the presence of either separate populations of blasts of more than one lineage, or one population of blasts co-expressing markers of more than one lineage.
• mixed phenotype acute leukemia with t(9;22)(q34.1;q11.2); bcr-abl1 - a rare mixed phenotype acute leukemia in which the blasts also carry the translocation t(9;22)(q34.1;q11.2) by karyotypic analysis or the bcr-abl1 translocation by fish or pcr. The prognosis is usually unfavorable.
• mixed phenotype acute leukemia with t(v;11q23.3); mll rearranged - a rare mixed phenotype acute leukemia in which the blasts carry a translocation between the mll (kmt2a) gene at 11q23.3 and another gene partner. The prognosis is usually unfavorable.
• mixed phenotype acute leukemia, b/myeloid, not otherwise specified - a rare mixed phenotype acute leukemia in which the blasts express b-lymphoid and myeloid lineage markers but are negative for mll translocation and t(9;22)(q34;q11.2) translocation. The prognosis is usually unfavorable.
• mixed phenotype acute leukemia, t/myeloid, not otherwise specified - a rare mixed phenotype acute leukemia in which the blasts express t-lymphoid and myeloid lineage markers but are negative for mll translocation and t(9;22)(q34;q11.2) translocation. The prognosis is usually unfavorable.
• mixed somatotroph and lactotroph adenoma - an infrequent pituitary gland adenoma composed of an admixture of acidophilic and chromophobic cells that produce growth hormone and prolactin respectively. Unlike mammosomatotroph adenomas, these two hormones are not localized in the same cell by immunohistochemistry.
• moderately differentiated prostate adenocarcinoma - an invasive prostate adenocarcinoma characterized by the presence of malignant cells exhibiting moderate differentiation.
• monoblastic sarcoma - a less common form of myeloid sarcoma composed of monoblasts. Monoblastic sarcoma may precede or occur simultaneously with acute monoblastic leukemia. (who 2001)
• monomorphic epitheliotropic intestinal t-cell lymphoma - a mature t-cell and nk-cell non-hodgkin lymphoma of intraepithelial t-lymphocytes. It usually arises from the small intestine. A minority of cases arise from the large intestine or the stomach. It is characterized by the presence of a monomorphic cellular infiltrate of small to medium-sized t-lymphocytes that are cytotoxic and express cd56. It is not associated with celiac disease.
• monomorphic post-transplant lymphoproliferative disorder - a clonal lymphoproliferative disorder arising as a result of post-transplant immunosuppression therapy. It is characterized by destructive infiltration of lymph nodes and extranodal sites by a monotonous population of transformed lymphocytes or plasma cells. It includes two variants: monomorphic b-cell and monomorphic t/nk cell post-transplant lymphoproliferative disorders.
• mu heavy chain disease - a clonal disorder characterized by the secretion of a mu heavy chain that lacks a variable region. Most patients present with slowly progressive chronic lymphocytic leukemia (cll). In contrast to most cases of cll, mu heavy chain disease is associated with hepatosplenomegaly and absence of lymphadenopathy.
• mucin-producing adenocarcinoma - an invasive adenocarcinoma composed of malignant glandular cells which produce mucin.
• mucinous adenocarcinoma - an invasive adenocarcinoma composed of malignant glandular cells which contain intracytoplasmic mucin. Often, the infiltrating glandular structures are associated with mucoid stromal formation. It may arise from the large and small intestine, appendix, stomach, lung, ovary, breast, corpus uteri, cervix, vagina, and salivary gland.
• mucinous tubular and spindle cell carcinoma of the kidney - a low grade carcinoma of the kidney characterized by the presence of tubules which are separated by mucinous stroma. Often the tubular structures have a spindle cell appearance. Patients are usually asymptomatic and occasionally they may present with hematuria or flank pain.
• multicystic mesothelioma - an intermediate grade neoplasm arising from mesothelial cells. It occurs in the peritoneum, extraperitoneal space, omentum, or pelvic or abdominal viscera. It is characterized by the presence of multiple cysts lined by flattened or cuboidal mesothelial cells. There is no evidence of significant cytologic atypia or increased mitotic activity. It usually occurs in young to middle-aged women. Patients present with abdominal or pelvic mass and pain. Approximately half of the cases recur. The recurrences may appear several years after the initial diagnosis. Rare cases of transformation to malignant mesothelioma have also been described.
• mycosis fungoides - a peripheral (mature) t-cell lymphoma presenting in the skin with patches/plaques. It is characterized by epidermal and dermal infiltration of small to medium-sized t-cells with cerebriform nuclei. Patients with limited disease generally have an excellent prognosis. In the more advanced stages, the prognosis is poor. (who, 2001)
• mycosis fungoides and sezary syndrome - mature t and nk neoplasms predominantly affecting the skin and the peripheral blood. Peripheral blood involvement by abnormal t-cells (cerebriform cells) is a late manifestation of mycosis fungoides, whereas it is the presenting finding in sezary syndrome.
• myelodysplastic syndrome - a clonal hematopoietic disorder characterized by dysplasia and ineffective hematopoiesis in one or more of the hematopoietic cell lines. The dysplasia may be accompanied by an increase in myeloblasts, but the number is less than 20%, which, according to the who guidelines, is the requisite threshold for the diagnosis of acute myeloid leukemia. It may occur de novo or as a result of exposure to alkylating agents and/or radiotherapy. (who, 2001)
• myelodysplastic syndrome with excess blasts - a myelodysplastic syndrome characterized by the presence of 5-19% myeloblasts in the bone marrow or 2-19% blasts in the peripheral blood. It includes two categories: myelodysplastic syndrome with excess blasts-1 and myelodysplastic syndrome with excess blasts-2.
• myelodysplastic syndrome with excess blasts and fibrosis - myelodysplastic syndrome with excess blasts associated with significant reticulin fibrosis of the bone marrow.
• myelodysplastic syndrome with excess blasts-1 - a myelodysplastic syndrome defined by 5-9% blasts in the bone marrow, and <5% blasts in the blood. Approximately 25% of cases progress to an acute leukemia. (who)
• myelodysplastic syndrome with excess blasts-2 - a myelodysplastic syndrome defined by 10-19% blasts in the bone marrow or 5-19% blasts in the blood. Approximately 33% of cases progress to acute leukemia. The prognosis is usually poor.
• myelodysplastic syndrome with isolated del(5q) - a myelodysplastic syndrome characterized by a deletion between bands q31 and 33 on chromosome 5. The number of blasts in the bone marrow and blood is <5%. The bone marrow is usually hypercellular or normocellular with increased number of often hypolobated megakaryocytes. The peripheral blood shows macrocytic anemia. This syndrome occurs predominantly but not exclusively in middle age to older women. The prognosis is good and transformation to acute leukemia is rare. (who, 2001)
• myelodysplastic syndrome with multilineage dysplasia - a myelodysplastic syndrome characterized by bi-cytopenia or pancytopenia and dysplastic changes in 10% or more of the cells in two or more of the myeloid cell lines. (who, 2001)
• myelodysplastic syndrome with ring sideroblasts - a myelodysplastic syndrome characterized by an anemia in which 15% or more of the erythroid precursors are ring sideroblasts. The ring sideroblast is an erythroid precursor in which one third or more of the nucleus is encircled by granules which are positive for iron stain. (who, 2001)
• myelodysplastic syndrome with ring sideroblasts and multilineage dysplasia - a myelodysplastic syndrome characterized by bi-cytopenia or pancytopenia, dysplastic changes in 10% or more of the cells in two or more of the myeloid cell lines, and 15% or more ring sideroblasts in the bone marrow. (who, 2001)
• myelodysplastic syndrome with ring sideroblasts and single lineage dysplasia - a myelodysplastic syndrome with ring sideroblasts and dysplastic changes involving only one myeloid cell lineage in the bone marrow.
• myelodysplastic syndrome with single lineage dysplasia - a myelodysplastic syndrome characterized by dysplastic changes involving only one myeloid cell lineage in the bone marrow. It primarily affects older adults and includes refractory anemia, refractory neutropenia, and refractory thrombocytopenia.
• myelodysplastic syndrome with somatic mutations - a myelodysplastic syndrome characterized by the presence of a point mutation in one of the following genes, tp53, ezh2, etv6, runx1, and asxl1. These gene mutations are independent predictors of poor prognosis.
• myelodysplastic syndrome, unclassifiable - a subtype of myelodysplastic syndrome which initially lacks findings appropriate for classification into any other myelodysplastic category. There are no specific morphologic findings. The diagnosis can be made in the following instances: 1. In cases of refractory cytopenia with unilineage dysplasia or refractory cytopenia with multilineage dysplasia but with 1% blasts in the peripheral blood; 2: in cases of myelodysplastic syndrome with unilineage dysplasia which are associated with pancytopenia; 3: in cases with persistent cytopenia (s) with 1% or fewer blasts in the blood and fewer than 5% in the bone marrow, unequivocal dysplasia in less than 10% of the cells in one or more myeloid lineages, and cytogenetic abnormalities considered as presumptive evidence of myelodysplastic syndrome. (who, 2008)
• myelodysplastic/myeloproliferative neoplasm - a category of clonal hematopoietic disorders that have both myelodysplastic and myeloproliferative features at the time of initial presentation.
• myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis - a myelodysplastic/myeloproliferative neoplasm with morphologic and clinical characteristics of refractory anemia with ring sideroblasts, marked thrombocytosis, and abnormal megakaryocytes.
• myelodysplastic/myeloproliferative neoplasm, unclassifiable - this entity includes cases that have clinical, laboratory, and morphologic features that support the diagnosis of both a myelodysplastic syndrome and a myeloproliferative neoplasm, but do not meet the criteria for any of the other entities included in the myelodysplastic/myeloproliferative neoplasm category. (who, 2001)
• myeloid leukemia associated with down syndrome - acute myeloid leukemia or myelodysplastic syndrome occurring in children with down syndrome. The acute myeloid leukemia is usually an acute megakaryoblastic leukemia, and is associated with gata1 gene mutation.
• myeloid proliferations associated with down syndrome - myeloid neoplasms occurring in individuals with down syndrome. There is an increased risk of acute leukemias in both children and adults with down syndrome. In particular, the incidence of acute myeloid leukemia in down syndrome children of less than five years of age is particularly high, it is usually an acute megakaryoblastic leukemia, and is associated with gata1 gene mutation. This group of disorders also includes the entity transient abnormal myelopoiesis which occurs in neonates and is associated with gata1 gene mutation.
• myeloid sarcoma - a tumor mass composed of myeloblasts or immature myeloid cells. It occurs in extramedullary sites or the bone. (who, 2001)
• myeloid/lymphoid neoplasms with eosinophilia and rearrangement of pdgfra, pdgfrb, or fgfr1, or with pcm1-jak2 - a group of rare myeloid and lymphoid neoplasms characterized by rearrangement of the pdgfra, pdgfrb, or fgfr1 genes, resulting in the formation of fusion transcripts and aberrant tyrosine kinase activity. Eosinophilia is a characteristic finding but it is not always present. This group includes the myeloid and lymphoid neoplasms with t(8;9)(p22;p24.1);pcm1-jak2 as a provisional entity.
• myeloid/lymphoid neoplasms with fgfr1 rearrangement - hematologic neoplasms characterized by the rearrangement of the fgfr1 gene, resulting in translocations with an 8p11 breakpoint. Patients present with a myeloproliferative neoplasm, acute myeloid leukemia, lymphoblastic lymphoma/leukemia of t or b-cell lineage, or acute leukemia of mixed phenotype.
• myeloid/lymphoid neoplasms with pdgfra rearrangement - hematologic neoplasms characterized by the rearrangement of the pdgfra gene, most often resulting in the formation of fip1l1-pdgfra fusion transcripts. Patients usually present with chronic eosinophilic leukemia, and less often with acute myeloid leukemia or t-lymphoblastic leukemia.
• myeloid/lymphoid neoplasms with pdgfrb rearrangement - myeloid and rarely lymphoid neoplasms characterized by the rearrangement of the pdgfrb gene, most often resulting in the formation of etv6-pdgfrb fusion transcripts. Patients usually present with chronic myelomonocytic leukemia and less often with atypical chronic myeloid leukemia, or chronic eosinophilic leukemia.
• myeloproliferative neoplasm - a clonal hematopoietic stem cell disorder, characterized by proliferation in the bone marrow of one or more of the myeloid (I.E., granulocytic, erythroid, megakaryocytic, and mast cell) lineages. It is primarily a neoplasm of adults. (who 2008)
• myeloproliferative neoplasm, unclassifiable - this subgroup of myeloproliferative neoplasms includes cases which do not meet the morphologic criteria of any of the defined myeloproliferative neoplasms, or which have characteristics that overlap at least two of the myeloproliferative neoplasms.
• myxoid chondrosarcoma - a chondrosarcoma characterized by the presence of myxoid changes.
• myxoid leiomyosarcoma - a morphologic variant of leiomyosarcoma characterized by the presence of cellular pleomorphism, malignant cells with large nuclei, and a myxoid stroma.
• myxoid liposarcoma - a liposarcoma characterized by the presence of round non-lipogenic primitive mesenchymal cells and small signet ring lipoblasts within a myxoid stoma with a branching vascular pattern. This category includes hypercellular lesions with round cell morphology, formerly known as round cell liposarcoma.
• myxopapillary ependymoma - a slow growing, who grade I glioma which generally occurs in young adults. It arises almost exclusively in the conus medullaris, cauda equina, and filum terminale of the spinal cord. It generally has a favorable prognosis and is characterized histologically by tumor cells arranged in a papillary manner around vascularized mucoid stromal cores. (adapted from who).
• nut carcinoma - a rare, highly aggressive and lethal carcinoma that affects children and young adults. It arises from midline epithelial structures, most commonly the head, neck, and mediastinum. It is a poorly differentiated carcinoma and is characterized by mutations and rearrangement of the nut gene. A balanced translocation t(15;19) is present that results in the creation of a fusion gene involving the nut gene, most commonly brd4-nut fusion gene.
• nasal cavity squamous cell carcinoma - a squamous cell carcinoma that arises from the nasal cavity mucosa. Signs and symptoms include nasal fullness and obstruction, pain, epistaxis, and the presence of a nasal mass.
• nasal type extranodal nk/t-cell lymphoma - an aggressive, predominantly extranodal, mature t-cell non-hodgkin lymphoma. It is characterized by an often angiocentric and angiodestructive cellular infiltrate composed of ebv positive nk/t cells. The nasal cavity is the most common site of involvement. Patients often present with midfacial destructive lesions (lethal midline granuloma). The disease may disseminate rapidly to various anatomic sites including the gastrointestinal tract, skin, testis, and cervical lymph nodes. It is also known as angiocentric t-cell lymphoma. The term "Polymorphic reticulosis" has been widely used to describe the morphologic changes seen in this type of lymphoma. However, the latter term may also apply to lymphomatoid granulomatosis, which is an angiocentric and angiodestructive ebv positive b-cell lymphoproliferative disorder.
• nasopharyngeal keratinizing squamous cell carcinoma - a squamous cell carcinoma that arises from the nasopharynx and is characterized by prominent production of keratin.
• neck carcinoma - a carcinoma that arises from the anatomic structures of the neck region.
• neoplastic post-transplant lymphoproliferative disorder - a lymphoproliferative disorder arising as a result of post-transplant immunosuppression therapy. It is characterized by the presence of tissue destruction and effacement of the architecture of the involved tissues. There is clonal rearrangement of the immunoglobulin or the t-cell receptor genes. It includes the following variants: polymorphic, monomorphic, and classical hodgkin lymphoma type post-transplant lymphoproliferative disorders.
• nerve sheath myxoma - a benign neoplasm arising from nerve sheaths. It is characterized by the presence of a myxoid stroma.
• neural glioblastoma - a molecular subtype of glioblastoma characterized by the expression of the neural markers nefl, gabra1, syt1, and slc12a5.
• neuroblastoma - a neuroblastic tumor characterized by the presence of neuroblastic cells, the absence of ganglion cells, and the absence of a prominent schwannian stroma formation.
• neuroendocrine carcinoma - a malignant epithelial neoplasm with neuroendocrine differentiation.
• neuroendocrine neoplasm - a benign or malignant neoplasm composed of cells of neuroendocrine origin. Representative examples include paraganglioma, carcinoid tumor, and neuroendocrine carcinoma.
• neurofibroma - an intraneural or extraneural neoplasm arising from nerve tissues and neural sheaths. It is composed of perineurial-like fibroblasts and schwann cells. It usually presents as a localized cutaneous lesion and less often as a circumscribed peripheral nerve mass. Patients with neurofibromatosis type 1 present with multiple masses. Neurofibromas which arise from major nerves and plexiform neurofibromas are precursor lesions to malignant peripheral nerve sheath tumors.
• nipple adenoma - a benign epithelial neoplasm arising from the nipple. Signs and symptoms include serous or sanguineous nipple discharge and nipple erosion. It is characterized by the presence of aggregates of small tubules replacing the nipple stroma. The tubules are lined by epithelial and myoepithelial cells.
• nipple carcinoma - a carcinoma that arises in the area of the nipple. Representative examples include paget disease and skin squamous cell carcinoma.
• nodal marginal zone lymphoma - a primary nodal b-cell non-hodgkin lymphoma which morphologically resembles lymph nodes involved by marginal zone lymphomas of extranodal or splenic types, but without evidence of extranodal or splenic disease. (who, 2001)
• nodular lymphocyte predominant hodgkin lymphoma - a monoclonal b-cell neoplasm characterized by a nodular, or a nodular and diffuse proliferation of scattered large neoplastic cells known as popcorn or lymphocyte predominant cells (lp cells)- formerly called l&h cells for lymphocytic and/or histiocytic reed-sternberg cell variants. The lp cells lack cd15 and cd30 in nearly all instances. Patients are predominantly male, frequently in the 30-50 year age group. Most patients present with limited stage disease (localized peripheral lymphadenopathy, stage I or ii). (who 2008)
• nodular sclerosis classic hodgkin lymphoma - a subtype of classic hodgkin lymphoma characterized by collagen bands that surround at least one nodule, and hodgkin and reed-sternberg cells with lacunar type morphology. (who, 2008)
• non-cutaneous melanoma - a melanoma that arises from a site other than skin.
• non-functioning pituitary gland adenoma - a hormone producing or non-producing pituitary gland adenoma not associated with a hormonal syndrome.
• non-gestational ovarian choriocarcinoma - a malignant germ cell tumor that arises from the ovary and is composed of cytotrophoblasts, syncytiotrophoblasts, and extravillous trophoblasts. The prognosis is less favorable than gestational choriocarcinoma.
• non-hereditary clear cell renal cell carcinoma - the most common type of renal cell carcinoma, characterized by a loss of genetic material of the short arm of chromosome 3. The most common symptom at the time of diagnosis is hematuria. The tumor has a golden-yellow color because of the abundance of intracytoplasmic lipid. This is a clinically aggressive type of renal cell carcinoma. The tumor usually metastasizes to unusual sites and late metastasis is common.
• non-hodgkin lymphoma - distinct from hodgkin lymphoma both morphologically and biologically, non-hodgkin lymphoma (nhl) is characterized by the absence of reed-sternberg cells, can occur at any age, and usually presents as a localized or generalized lymphadenopathy associated with fever and weight loss. The clinical course varies according to the morphologic type. Nhl is clinically classified as indolent, aggressive, or having a variable clinical course. Nhl can be of b-or t-/nk-cell lineage.
• non-secretory plasma cell myeloma - a rare type of multiple myeloma in which the plasma cells synthesize but do not secrete immunoglobulins. As a result, none of the immunoglobulins appear out of the normal range. The symptoms are generally the same with those of immunoglobulin-secreting myeloma; however, the incidence of renal insufficiency is lower in non-secretory myeloma. The diagnosis can be missed because of the absence of monoclonal immunoglobulin in the serum or urine.
• nonanaplastic kidney wilms tumor - wilms tumor of the kidney characterized by the absence of nuclear anaplasia.
• noninvasive malignant thymoma - a morphologically malignant thymoma that is entirely confined within the capsule.
• normal breast-like subtype of breast carcinoma - a biologic subset of breast carcinoma defined by high expression of many genes expressed by adipose and other non-epithelial tissues.
• null cell pituitary gland adenoma - a non-functioning pituitary gland adenoma without hormonal immunoreactivity or evidence of specific adenohypophysial cell derivation.
• ocular adnexal mucosa-associated lymphoid tissue lymphoma - an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue that arises from the ocular adnexa. It is the most common type of primary ocular adnexal lymphoma.
• olfactory neuroblastoma - a rare neuroectodermal tumor originating from olfactory receptor cells in the nasal cavity or paranasal sinuses. Microscopically, it is characterized by neuroblastic differentiation with occasional formation of rosettes. If the tumor is not resected at an early stage, the prognosis is usually poor.
• oligoastrocytoma - a who grade ii tumor composed of a conspicuous mixture of two distinct neoplastic cell types morphologically resembling the tumor cells in oligodendroglioma and diffuse astrocytoma. (who)
• oligodendroglial tumor - a neoplasm of the central nervous system composed predominantly of cells morphologically resembling oligodendroglia. Oligodendroglial tumors histologically comprise a continuous spectrum ranging from well-differentiated neoplasms to frankly malignant tumors. Who grading system recognizes two malignancy grades: who grade ii for well-differentiated tumors (oligodendroglioma) and who grade iii for anaplastic oligodendroglioma. (adapted from who)
• oligodendroglioma - a well-differentiated (who grade ii), diffusely infiltrating neuroglial tumor, typically located in the cerebral hemispheres. It is composed predominantly of cells which morphologically resemble oligodendroglia. The neoplastic cells have rounded homogeneous nuclei and, on paraffin sections, a swollen, clear cytoplasm ('honeycomb' appearance). (adapted from who)
• oligodendroglioma, idh-mutant and 1p/19q-codeleted - an oligodendroglioma carrying idh gene family mutation and combined whole-arm losses of 1p and 19q (1p/19q codeletion).
• oligodendroglioma, not otherwise specified - an oligodendroglioma in which there is insufficient information on the idh genes and 1p/19q codeletion status.
• oncocytic adenocarcinoma - an adenocarcinoma characterized by the presence of large malignant epithelial cells with abundant granular eosinophilic cytoplasm (oncocytes). Representative examples include thyroid gland oncocytic follicular carcinoma, oncocytic breast carcinoma, and salivary gland oncocytic carcinoma.
• oral cavity carcinoma - a carcinoma arising in the oral cavity. Most oral cavity carcinomas are squamous cell carcinomas of the tongue, buccal mucosa, or gums. Less frequent morphologic variants include mucoepidermoid carcinoma and adenocarcinoma.
• oral cavity pleomorphic adenoma - a benign, slow-growing and painless neoplasm that arises from the salivary glands in the oral cavity. It is composed of cells that demonstrate both epithelial and mesenchymal differentiation.
• oral cavity squamous cell carcinoma - a squamous cell carcinoma arising from the oral cavity. It affects predominantly adults in their fifth and sixth decades of life and is associated with alcohol and tobacco use. Human papillomavirus is present in approximately half of the cases. It is characterized by a tendency to metastasize early to the lymph nodes. When the tumor is small, patients are often asymptomatic. Physical examination may reveal erythematous or white lesions or plaques. The majority of patients present with signs and symptoms of locally advanced disease including mucosal ulceration, pain, difficulty with speaking, chewing, and swallowing, bleeding, weight loss, and neck swelling. Patients may also present with swollen neck lymph nodes without any symptoms from the oropharyngeal tumor. The most significant prognostic factors are the size of the tumor and the lymph nodes status.
• oropharyngeal squamous cell carcinoma - a squamous cell carcinoma arising from the oropharynx. It predominantly affects adults in their fifth and sixth decades of life and is associated with alcohol and tobacco use. Human papillomavirus is present in approximately half of the cases. It is characterized by a tendency to metastasize early to the lymph nodes. When the tumor is small, patients are often asymptomatic. Physical examination may reveal erythematous or white lesions or plaques. The majority of patients present with locally advanced disease. Signs and symptoms include mucosal ulceration, pain, bleeding, weight loss, neck swelling, and difficulty speaking, chewing, and swallowing. Patients may also present with swollen neck lymph nodes without any symptoms from the oropharyngeal tumor. The most significant prognostic factors are the size of the tumor and the lymph nodes status.
• osteoblastic osteosarcoma - a conventional osteosarcoma characterized by the predominance of osteoid matrix.
• osteoblastoma - a rare benign bone-forming neoplasm usually arising from the spine. It is a well-circumscribed lytic tumor that varies in size. The tumor is composed of woven bone trabeculae and shares similar histologic characteristics with the osteoid osteoma. Surgical curettage is the treatment of choice. The prognosis is excellent.
• osteoclastic giant cell-rich tumor of bone - a benign, intermediate, or malignant bone tumor characterized by the presence of osteoclast-like giant cells. Clinical presentation includes pain, edema, and decreased range of motion in the affected joint.
• osteoid osteoma - a small, benign, bone-forming neoplasm that can arise from any bone but more frequently affects the long bones. The central portion of the neoplasm (nidus) contains differentiated osteoblasts which produce osteoid and sometimes bone. The lesion is usually surrounded by hypervascular sclerotic bone and has limited growth potential. Clinical signs and symptoms include pain and localized tenderness, at the site of the lesion. The pain may be intense but in the majority of cases it is completely alleviated by non-steroidal anti-inflammatory drugs. Prognosis is excellent and recurrences are rare.
• osteoma - a benign, well-circumscribed, bone-forming neoplasm predominantly composed of lamellar bone. It usually arises from the calvarial, facial, or jaw bones. It is usually asymptomatic but it may cause local swelling or obstruction of the paranasal sinuses. Asymptomatic cases have an indolent clinical course.
• osteosarcoma - a usually aggressive malignant bone-forming mesenchymal neoplasm, predominantly affecting adolescents and young adults. It usually involves bones and less frequently extraosseous sites. It often involves the long bones (particularly distal femur, proximal tibia, and proximal humerus). Pain with or without a palpable mass is the most frequent clinical symptom. It may spread to other anatomic sites, particularly the lungs.
• osteosarcoma arising in paget disease of bone - a sarcomatous transformation of pre-existing paget disease of the bone. Osteosarcomas arising from paget disease of the bone are high grade lesions and usually have a poor prognosis.
• osteosclerotic plasma cell myeloma - a plasma cell neoplasm associated with osteosclerotic and fibrotic changes in the bone trabeculae. Often, the lymph nodes show changes resembling the plasma cell variant of castleman disease. It is often part of poems syndrome which is characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes.
• ovarian adenocarcinoma - an adenocarcinoma that arises from the ovary. It is the most common type of ovarian carcinoma. It includes the serous adenocarcinoma, mucinous adenocarcinoma, clear cell adenocarcinoma, and endometrioid adenocarcinoma.
• ovarian carcinoma - a malignant neoplasm originating from the surface ovarian epithelium. It accounts for the greatest number of deaths from malignancies of the female genital tract and is the fifth leading cause of cancer fatalities in women. It is predominantly a disease of older white women of northern european extraction, but it is seen in all ages and ethnic groups. Adenocarcinomas constitute the vast majority of ovarian carcinomas. The pattern of metastatic spread in ovarian carcinoma is similar regardless of the microscopic type. The most common sites of involvement are the contralateral ovary, peritoneal cavity, para-aortic and pelvic lymph nodes, and liver. Lung and pleura are the most common sites of extra-abdominal spread. The primary form of therapy is surgical. The overall prognosis of ovarian carcinoma remains poor, a direct result of its rapid growth rate and the lack of early symptoms.
• ovarian clear cell adenocarcinoma - a malignant glandular epithelial neoplasm characterized by the presence of clear and hobnail cells. It is highly associated with ovarian endometriosis, pelvic endometriosis and paraendocrine hypercalcemia.
• ovarian cystadenocarcinoma - an adenocarcinoma that arises from the ovary and is characterized by the presence of cystic structures. It includes the serous cystadenocarcinoma, mucinous cystadenocarcinoma, and clear cell cystadenocarcinoma.
• ovarian endometrioid adenocarcinoma - an endometrioid adenocarcinoma arising from the ovary. It comprises 10% to 25% of all primary ovarian carcinomas. Grossly, endometrioid carcinoma may present as a cystic or solid mass. Microscopically, the tumor greatly resembles the appearance of the ordinary type of endometrial adenocarcinoma. As a group, endometrioid carcinoma has a prognosis twice as good as that of serous or mucinous carcinoma.
• ovarian germ cell tumor - a neoplasm that arises from the ovary and originates from germ cells. Representative examples include teratoma, embryonal carcinoma, yolk sac tumor, and dysgerminoma.
• ovarian mucinous adenocarcinoma - an invasive adenocarcinoma that arises from the ovary and is characterized by the presence of malignant epithelial cells that contain intracytoplasmic mucin. There is cellular atypia, increased layering of cells, complexity of glands, and papillary formations.
• ovarian mucinous cystadenoma - a benign neoplasm of the ovary characterized by the presence of cystic structures lined by mucinous columnar epithelial cells.
• ovarian serous adenocarcinoma - an adenocarcinoma that arises from the ovary and is characterized by the presence of malignant epithelial cells that, in well differentiated tumors, resemble the epithelium of the fallopian tube or, in poorly differentiated tumors, show anaplastic features and marked nuclear atypia.
• ovarian serous cystadenoma - a benign, usually bilateral neoplasm of the ovary characterized by the presence of cystic structures that contain watery fluid and are lined by serous epithelial cells. Signs and symptoms include abdominal enlargement, pain, and vaginal bleeding.
• ovarian small cell carcinoma - a carcinoma that arises from the ovary and is characterized by the presence of small malignant cells. It includes small cell carcinoma, hypercalcemic type and small cell carcinoma, pulmonary type.
• ovarian squamous cell carcinoma - a usually high grade squamous cell carcinoma that arises from the ovary and is not associated with a germ cell tumor. The prognosis is poor.
• ovarian transitional cell carcinoma - a carcinoma that arises from the ovary and is characterized by the presence of malignant epithelial cells that resemble malignant urothelial cells. There is no morphologic evidence of a benign or borderline brenner tumor component present.
• ovarian undifferentiated carcinoma - an aggressive carcinoma arising from the ovary. Most patients present with advanced disease. Microscopically, it is characterized by significant cytologic atypia, increased mitotic activity, and necrosis. The prognosis is usually poor.
• overt primary myelofibrosis - primary myelofibrosis characterized by reticulin or collagen fibrosis in the bone marrow. The bone marrow is usually normocellular or hypocellular. Myeloblasts account for less than 10% of the bone marrow cells. Atypical megakaryocytes are present.
• paget disease - a malignant neoplasm composed of large cells with large nuclei, prominent nucleoli, and abundant pale cytoplasm (paget cells). Paget cell neoplasms include paget disease of the nipple and extramammary paget disease which may affect the vulva, penis, anus, skin and scrotum.
• palate squamous cell carcinoma - a squamous cell carcinoma that arises from the hard or soft palate.
• pancreatic acinar cell carcinoma - an adenocarcinoma arising from the pancreas. It is characterized by the presence of relatively uniform malignant cells which form acinar patterns. It usually occurs during adulthood. Signs and symptoms include abdominal pain, weight loss, nausea, and diarrhea. It may metastasize to regional lymph nodes and the liver. A minority of patients develop lipase hypersecretion syndrome. This syndrome may be seen in patients with liver metastases and it is characterized by excessive secretion of lipase in the serum, polyarthralgia, and subcutaneous fat necrosis.
• pancreatic adenocarcinoma - an adenocarcinoma which arises from the exocrine pancreas. Ductal adenocarcinoma and its variants are the most common types of pancreatic adenocarcinoma.
• pancreatic carcinoma - a carcinoma arising from the exocrine pancreas. The overwhelming majority of pancreatic carcinomas are adenocarcinomas.
• pancreatic cystadenocarcinoma - a cystic adenocarcinoma that arises from the pancreas. It includes the acinar cell and serous cystadenocarcinoma subtypes.
• pancreatic cystadenoma - a non-metastasizing cystic epithelial neoplasm arising from the exocrine pancreas.
• pancreatic delta cell neuroendocrine tumor - a usually malignant neuroendocrine tumor arising from the delta cells of the pancreas. It may be associated with inappropriate secretion of somatostatin and an associated clinical syndrome, or it may be hormonally inactive (non-functioning).
• pancreatic ductal adenocarcinoma - an infiltrating adenocarcinoma that arises from the epithelial cells of the pancreas. It affects males more often than females and the patients are usually over 50 years of age. Microscopically it is characterized by the presence of glandular (ductal) differentiation and desmoplastic stroma formation. Signs and symptoms include pain, loss of weight, and jaundice. It grows rapidly and is usually detected after it has metastasized to other anatomic sites. The prognosis is usually poor.
• pancreatic gastrin-producing neuroendocrine tumor - a usually malignant gastrin-producing neuroendocrine tumor arising from the pancreas. It may or may not be associated with inappropriate secretion of gastrin and an associated clinical syndrome.
• pancreatic glucagon-producing neuroendocrine tumor - a usually malignant, glucagon-producing neuroendocrine tumor arising from the pancreatic alpha cells. It may or may not be associated with inappropriate secretion of glucagon and an associated clinical syndrome.
• pancreatic insulin-producing neuroendocrine tumor - an insulin-producing neuroendocrine tumor arising from the beta cells of the pancreas. It may or may not be associated with inappropriate secretion of insulin and an associated clinical syndrome.
• pancreatic intraductal papillary-mucinous neoplasm with an associated invasive carcinoma - a pancreatic intraductal papillary mucinous neoplasm characterized by the presence of a focal or multifocal invasive carcinomatous component. The invasive carcinoma is either colloid or ductal adenocarcinoma.
• pancreatic intraductal tubulopapillary neoplasm with an associated invasive carcinoma - a pancreatic intraductal tubulopapillary neoplasm characterized by the presence of an invasive carcinomatous component. The invasive carcinoma has a tubular pattern.
• pancreatic large cell neuroendocrine carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the pancreas. It is characterized by the presence of malignant large cells.
• pancreatic macrocystic serous cystadenoma - a benign, non-metastasizing epithelial neoplasm arising from the exocrine pancreas. It is characterized by the presence of a few large cysts and is composed of glycogen-rich epithelial cells which produce a watery fluid.
• pancreatic mixed acinar-ductal carcinoma - a carcinoma that arises from the pancreas showing either extensive mucin accumulation and acinar neoplastic cells or a mixture of columnar or signet-ring cells and acinar neoplastic cells.
• pancreatic neuroendocrine carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the pancreas. The mitotic count is more than 20 per 10 hpf. According to the size of the malignant cells, the prominence of the nucleoli, and the amount of cytoplasm, it is classified either as small or large cell neuroendocrine carcinoma.
• pancreatic neuroendocrine tumor - a low or intermediate grade well differentiated tumor with neuroendocrine differentiation that arises from the pancreas. According to the presence or absence of clinical syndromes that result from hormone hypersecretion, pancreatic neuroendocrine tumors are classified either as functional or nonfunctional.
• pancreatic neuroendocrine tumor g1 - a low grade well differentiated tumor with neuroendocrine differentiation that arises from the pancreas. The mitotic count is less than 2 per 10 hpf and/or the ki67 index is equal or less than 2%.
• pancreatic neuroendocrine tumor g2 - an intermediate grade well differentiated tumor with neuroendocrine differentiation that arises from the pancreas. The mitotic count is 2-20 per 10 hpf and/or the ki67 index is 3-20%.
• pancreatic serous cystadenoma - a benign, non-metastasizing cystic epithelial neoplasm arising from the exocrine pancreas. It is composed of glycogen-rich epithelial cells which produce a watery fluid. Signs and symptoms include abdominal mass, abdominal pain, nausea, vomiting, and weight loss.
• pancreatic small cell carcinoma - an aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the pancreas. It is characterized by the presence of malignant small cells.
• pancreatic vip-producing neuroendocrine tumor - a usually malignant pancreatic neuroendocrine tumor producing vasoactive intestinal peptide (vip). It may or may not be associated with inappropriate secretion of vip and an associated clinical syndrome.
• papillary carcinoma - a malignant epithelial neoplasm characterized by a papillary growth pattern. A papillary carcinoma may be composed of glandular cells (papillary adenocarcinoma), squamous cells (papillary squamous cell carcinoma), or transitional cells (papillary transitional cell carcinoma). Bladder carcinoma is a representative example of papillary transitional cell carcinoma.
• papillary ependymoma - a rare variant of ependymoma characterized by well formed papillae. Tumor cell processes abutting capillaries are usually gfap-positive. Differential diagnoses include choroid plexus papilloma, papillary meningioma and metastatic papillary carcinoma. (adapted from who)
• papillary glioneuronal tumor - a who grade I, indolent and relatively circumscribed brain tumor. Morphologically it is characterized by the presence of astrocytes that line vascular and hyalinized pseudopapillae. In between the pseudopapillae aggregates of neurocytes, large neurons, and ganglioid cells are present.
• papillary intralymphatic angioendothelioma - an intermediate, rarely metastasizing blood vessel neoplasm. It is characterized by the presence of lymphatic-like vascular channels and papillary endothelial proliferation.
• papillary meningioma - a who grade iii meningioma characterized by the predominance of a perivascular pseudopapillary pattern.
• papillary renal cell carcinoma - also known as chromophil carcinoma, it represents a minority of renal cell carcinomas. It can be hereditary or sporadic. The sporadic papillary renal cell carcinoma is characterized by trisomy of chromosomes 7, 16, and 17, and loss of chromosome y. The peak incidence is in the sixth and seven decades. It is classified as type 1 or 2, based on the cytoplasmic volume and the thickness of the lining neoplastic cells. The prognosis is more favorable than for conventional (clear cell) renal cell carcinoma.
• papillary tumor of the pineal region - a rare tumor that arises from the pineal region and affects adults. It is characterized by the presence of neuroepithelial cells and a papillary architecture. Electron microscopic studies suggest ependymal differentiation. The clinical course is variable.
• papilloma - a benign epithelial neoplasm that projects above the surrounding epithelial surface and consists of villous or arborescent outgrowths of fibrovascular stroma.
• paraganglioma - a benign or malignant neoplasm arising from paraganglia located along the sympathetic or parasympathetic nerves. Infrequently, it may arise outside the usual distribution of the sympathetic and parasympathetic paraganglia. Tumors arising from the adrenal gland medulla are called pheochromocytomas. Morphologically, paragangliomas usually display a nesting (zellballen) growth pattern. There are no reliable morphologic criteria to distinguish between benign and malignant paragangliomas. The only definitive indicator of malignancy is the presence of regional or distant metastases.
• paranasal sinus squamous cell carcinoma - a squamous cell carcinoma that arises from the mucosal epithelial surface of the ethmoid, frontal, maxillary, or sphenoid sinus. Patients may present with nasal fullness, obstruction, and/or epistaxis.
• parathyroid gland adenoma - a neoplasm arising from the parenchymal cells of the parathyroid glands. In the vast majority of cases, the tumor involves a single parathyroid gland. It is associated with the symptoms of primary hyperparathyroidism, resulting from the excessive production of parathyroid hormone. It is usually surrounded by a well-defined capsule. Capsular invasion, vascular invasion, and perineural invasion are absent. Overall cure rates are excellent following excision of the abnormal gland(s).
• parathyroid gland carcinoma - a malignant tumor arising from the parenchymal cells of the parathyroid gland. It is associated with the symptoms of primary hyperparathyroidism, resulting from the excessive production of parathyroid hormone. Morphologically, the differential diagnosis from parathyroid gland adenoma may be difficult. A definitive diagnosis of carcinoma is made only in the presence of capsular invasion, vascular invasion, and/or perineural invasion.
• parotid gland adenocarcinoma - an adenocarcinoma that arises from the parotid gland. Representative examples include acinic cell carcinoma, basal cell adenocarcinoma, cystadenocarcinoma, and oncocytic carcinoma.
• parotid gland adenoid cystic carcinoma - an aggressive carcinoma that arises from the parotid gland. It is characterized by the presence of malignant epithelial and myoepithelial cells forming cribriform, tubular, and solid patterns. It usually presents as a slow growing mass. Patients develop pain because of the tendency of these carcinomas to invade perineural tissues.
• parotid gland carcinoma - a carcinoma that arises from the parotid gland. Representative examples include mucoepidermoid carcinoma, adenoid cystic carcinoma, adenocarcinoma, and carcinoma ex pleomorphic adenoma.
• parotid gland carcinoma ex pleomorphic adenoma - a carcinoma that arises from a pleomorphic adenoma in the parotid gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.
• parotid gland carcinosarcoma - an aggressive, high grade malignant tumor that arises from the parotid gland. It is characterized by the presence of a malignant epithelial and a sarcomatous component.
• parotid gland monomorphic adenoma - a benign epithelial neoplasm that arises from the parotid gland. It is characterized by the presence of a monomorphic cellular infiltrate.
• parotid gland mucoepidermoid carcinoma - a carcinoma that arises from the parotid gland. It usually presents as a firm and painless mass. It is characterized by the presence of epidermoid cells, mucus producing cells, and cells of intermediate type. It usually spreads to pre-auricular lymph nodes. The majority of cases have a favorable outcome.
• parotid gland pleomorphic adenoma - a benign, slow-growing tumor that arises from the parotid gland. It is composed of cells that demonstrate both epithelial and mesenchymal differentiation. It is the most common neoplasm of salivary gland origin and women are more often affected than men.
• parotid gland squamous cell carcinoma - an invasive squamous cell carcinoma that arises from the parotid gland. It usually affects elderly patients and presents as a rapidly enlarging tumor mass, often associated with pain.
• parotid gland undifferentiated carcinoma - a carcinoma that arises from the parotid gland and is characterized by the presence of undifferentiated, anaplastic malignant epithelial cells.
• parotid gland warthin tumor - an adenoma that arises from the parotid gland. It is characterized by an oncocytic, often papillary, epithelial component, dense lymphoid stroma, and cystic spaces. A strong association with smoking has been reported. It typically presents as a painless swelling in the lower portion of the parotid gland.
• pediatric nodal marginal zone lymphoma - a nodal marginal zone lymphoma affecting the pediatric population, predominantly males. It presents with asymptomatic and localized (mainly head and neck) disease in the vast majority of cases. Morphologically there is often progressive transformation of the germinal centers. The prognosis is excellent.
• pediatric-type follicular lymphoma - a nodal follicular lymphoma with favorable prognosis. It lacks bcl-2 rearrangement and 14;18 translocation. Nearly all cases are localized. It is usually seen in the pediatric population but similar lymphomas may occur in adults.
• penile basal cell carcinoma - a basal cell carcinoma of the penis with an indolent clinical course. It is usually superficial and arises from the shaft and rarely the glans.
• penile bowenoid papulosis - a cutaneous, usually multifocal lesion in the penis characterized by the presence of verrucous papules. It is caused by human papillomavirus infection. Morphologically there is bowenoid dysplasia present. Progression to invasive carcinoma is infrequent.
• penile carcinoma - a carcinoma that arises from the penis. Risk factors include phimosis and human papillomavirus infection. The majority of penile carcinomas are squamous cell carcinomas. The most frequent clinical presentation is an irregular mass in the glans of the penis. Treatment includes surgical management and radiation therapy.
• penile paget disease - a rare, slow-growing, usually non-invasive intraepithelial adenocarcinoma affecting the penile skin or mucosal surface. The malignant cells are large with abundant pale cytoplasm and vesicular nuclei with prominent nucleoli. (who 2016)
• periampullary adenocarcinoma - an adenocarcinoma that arises from the periampullary region.
• pericardial malignant mesothelioma - a rare malignant mesothelioma that arises from the pericardium. Clinical presentation includes pericardial effusion, congestive heart failure, a mass or cardiac tamponade. Surgical resection is the treatment of choice. Adjunct treatments of chemotherapy or radiation have not improved outcomes. The prognosis is extremely poor due to its late presentation and difficulty obtaining complete surgical excision. In most cases the diagnosis is made at autopsy or postoperatively.
• perineurioma - a rare benign tumor composed entirely of neoplastic perineurial cells. It may occur in the soft tissues, intraneurally or in mucosal sites.
• periosteal chondroma - a benign neoplasm of bone surface composed of hyaline cartilage. It arises beneath the periosteum and is characterized by the presence of chondrocytes, a lobulated growth pattern, and calcification.
• periosteal chondrosarcoma - a chondrosarcoma arising from the surface of bone. It is characterized by a lobulated growth pattern, high mitotic activity, myxoid stroma formation, and necrotic changes. It occurs in adults. Clinical presentation includes pain, and sometimes swelling.
• peripheral ganglioneuroblastoma - a ganglioneuroblastoma arising from the peripheral nervous system.
• peripheral neuroblastoma - a neuroblastoma arising from the peripheral nervous system.
• peripheral primitive neuroectodermal tumor - a small round cell tumor with neural differentiation arising from the soft tissues or bone.
• peripheral primitive neuroectodermal tumor of bone - a small round cell tumor with neural differentiation arising from the bone. It may be associated with pain.
• peripheral primitive neuroectodermal tumor of soft tissues - a small round cell tumor with neural differentiation arising from the soft tissues.
• peripheral t-cell lymphoma, not otherwise specified - a heterogenous category of nodal and extranodal mature t-cell lymphomas that do not correspond to any of the specifically defined entities of mature t-cell lymphoma in the 2017 who classification. Excluded from this category are tumors with a t follicular helper (tfh) cell phenotype. Variants include lymphoepithelioid lymphoma (lennert lymphoma) and primary ebv-positive nodal t-cell or nk-cell lymphoma. The follicular variant included in the peripheral t-cell lymphomas, not otherwise specified, in the 2008 edition of the who classification has been moved to the category of angioimmunoblastic t-cell lymphoma and other nodal lymphomas of t follicular helper cell origin in the 2017 who update. The same is true for a proportion of cases previously designated as the t-zone variant, because they usually have a tfh-cell phenotype. (who 2017)
• peritoneal malignant mesothelioma - an aggressive malignant mesothelioma that arises from the peritoneum. Patients usually present with abdominal pain and ascites.
• peritoneal multicystic mesothelioma - a cystic mesothelioma that arises from the peritoneum and usually affects young to middle aged females. Grossly, it presents as a large multiloculated tumor mass, usually in the pelvic peritoneum. Histologically it is characterized by the presence of multiple cysts that are lined by one or more layers of mesothelial cells that do not show atypia. Patients usually present with abdominal or pelvic mass and pain. The clinical course is indolent. The tumor may recur, but transformation to diffuse malignant mesothelioma is rare.
• peritoneal well differentiated papillary mesothelioma - a localized or multifocal mesothelioma arising from the peritoneum. It predominantly occurs in women. It is characterized by the formation of papillae, covered by a single layer of blunt mesothelial cells. Mitotic figures are not present. There is no evidence of severe cytologic atypia. It has a relatively favorable clinical outcome, compared to diffuse malignant mesothelioma.
• ph-like acute lymphoblastic leukemia - a leukemia subtype characterized by a gene-expression profile similar to that of bcr-abl1-positive acute lymphoblastic leukemia, alterations of lymphoid transcription factor genes, and a poor outcome.
• pharyngeal squamous cell carcinoma - a squamous cell carcinoma that arises from the pharynx.
• philadelphia chromosome negative, bcr-abl1 positive chronic myelogenous leukemia - a chronic myelogenous leukemia which does not have the characteristic t(9;22)(q34;q11.2) translocation but it has either a variant translocation or a cryptic translocation that can not be detected by conventional cytogenetic analysis. In such cases the bcr-abl1 fusion gene is always detected by rt-pcr, fish, or southern blot analysis.
• philadelphia chromosome positive, bcr-abl1 positive chronic myelogenous leukemia - a chronic myelogenous leukemia characterised by the t(9;22)(q34;q11) chromosomal translocation, resulting in the presence of the philadelphia chromosome and the bcr-abl1 fusion gene.
• phyllodes tumor - a benign, borderline, or malignant fibroepithelial neoplasm arising from the breast and rarely the prostate gland. It may recur following resection. The recurrence rates are higher for borderline and malignant phyllodes tumors. In borderline and malignant phyllodes tumors metastases to distant anatomic sites can occur. The incidence of metastases is higher in malignant phyllodes tumors.
• pilocytic astrocytoma - a who grade I, relatively circumscribed, slowly growing, often cystic astrocytoma occurring in children and young adults. Histologically it is characterized by a biphasic pattern with compacted bipolar cells associated with rosenthal fibers and multipolar cells associated with microcysts and eosinophilic bodies/hyaline droplets. (who)
• pilomatrical carcinoma - a very rare, locally aggressive, malignant neoplasm of the hair follicle. The majority of the cases arise de novo, however malignant transformation from a pre-existing pilomatricoma has been reported. It usually presents as a solitary nodule in the head and neck, upper extremities, or buttocks. Morphologically, it is characterized by the presence of aggregates of basaloid cells infiltrating the dermis. Masses of ghost cells are present in the cellular aggregates. Complete surgical excision is the treatment of choice. If it is not completely removed, it usually recurs, but it rarely metastasizes to distant anatomic sites.
• pilomatricoma - a benign adnexal neoplasm arising from hair-bearing skin surfaces, usually the head and neck and upper extremities. It usually presents as a solitary, slow-growing nodular mass. Morphologically, it displays differentiation towards the matrix and inner sheath of the normal hair follicle and the hair cortex. Complete surgical excision is usually curative. Occasionally, it may recur.
• pilomyxoid astrocytoma - an astrocytic tumor of uncertain relation to pilocytic astrocytoma. It occurs predominantly in infants and young children. It is characterized by a monomorphic architectural pattern, usually associated with the absence of rosenthal fibers and eosinophilic granular bodies. The clinical course is usually aggressive.
• pineal parenchymal cell neoplasm - a neoplasm arising from the pineocyte, a cell with photosensory and neuroendocrine functions. It may be composed of mature elements or primitive, immature cells. The cellular composition determines the biological behavior and clinical outcome. Three types are recognized: pineoblastoma, pineocytoma, and pineal parenchymal tumor of intermediate differentiation (adapted from who.)
• pineal parenchymal tumor of intermediate differentiation - a who grade ii or iii pineal parenchymal neoplasm of intermediate-grade malignancy, affecting all ages. It is composed of diffuse sheets or large lobules of uniform cells with mild to moderate nuclear atypia and low to moderate level mitotic activity. (adapted from who)
• pineoblastoma - a poorly differentiated malignant embryonal neoplasm arising from the pineal region. It usually occurs in children and it is characterized by the presence of small immature neuroepithelial cells. It may follow an aggressive clinical course.
• pineocytoma - a who grade I slow growing tumor, more frequently affecting young adults. It is composed of small, uniform, mature cells resembling pineocytes with occasional large pineocytomatous rosettes. It may show a wide range of divergent phenotypes, including neuronal, glial, melanocytic, photoreceptor and mesenchymal differentiation. Pineocytoma generally has a relatively favorable prognosis. (adapted from who)
• pituitary gland adenoma - a non-metastasizing tumor that arises from the adenohypophysial cells of the anterior lobe of the pituitary gland. The tumor can be hormonally functioning or not. The diagnosis can be based on imaging studies and/or radioimmunoassays. Due to its location in the sella turcica, expansion of the tumor mass can impinge on the optic chiasm or involve the temporal lobe, third ventricle and posterior fossa a frequently associated physical finding is bitemporal hemianopsia which may progress to further visual loss.
• pituitary gland carcinoma - a rare adenocarcinoma with poor prognosis, arising from the adenohypophysial cells of the anterior lobe of the pituitary gland or pre-existing adenomas. The majority are hormonally functioning neoplasms, usually producing prolactin or acth. The diagnosis is based on the presence of metastases. Syndromes associated with pituitary gland carcinomas include hyperprolactinemia, cushing disease, and acromegaly.
• pituitary gland macroadenoma - a pituitary gland adenoma with a diameter greater than 10 mm. Clinical manifestations include headache, visual field disturbances, pituitary insufficiency, and mild hyperprolactinemia.
• pituitary gland microadenoma - a pituitary gland adenoma with a diameter equal or less than 10 mm.
• plasma cell leukemia - an aggressive plasma cell neoplasm characterized by the presence of neoplastic plasma cells in the peripheral blood. It is characterized by the presence of a circulating clonal plasma cell count that exceeds 2x10^9/l or is 20% of the leukocyte differential count.
• plasma cell myeloma - a bone marrow-based plasma cell neoplasm characterized by a serum monoclonal protein and skeletal destruction with osteolytic lesions, pathological fractures, bone pain, hypercalcemia, and anemia. Clinical variants include non-secretory myeloma, smoldering myeloma, indolent myeloma, and plasma cell leukemia. (who, 2001)
• plasma cell myeloma post-transplant lymphoproliferative disorder - a lymphoproliferative disorder that develops following an organ transplantation and exhibits plasma cell myeloma features.
• plasmablastic lymphoma - an aggressive diffuse large b-cell lymphoma frequently arising in the setting of hiv infection and characterized by the presence of large neoplastic cells resembling b-immunoblasts which have the immunophenotypic profile of plasma cells. Sites of involvement include the oral cavity, sinonasal cavity, skin, soft tissues, gastrointestinal tract, and bone.
• plasmacytoma - a malignant (clonal) proliferation of plasma cells that are cytologically and immunophenotypically identical to those of plasma cell myeloma, but manifest a localized osseous or extraosseous growth pattern. (who, 2001)
• pleomorphic adenoma - a neoplasm characterized by the presence of benign epithelial and myoepithelial cells and a mesenchymal component that may contain mucoid, myxoid, cartilaginous, or osseous areas. It may be completely or partially encapsulated. It occurs in the parotid gland, submandibular gland, minor salivary glands in the oral cavity, upper respiratory tract, and nasal cavity and paranasal sinuses. It usually presents as a slow growing painless mass. Infrequently, patients may present with pain and facial palsy. It may recur after excision or transform to a malignant neoplasm (carcinoma ex pleomorphic adenoma).
• pleomorphic liposarcoma - a liposarcoma characterized by the presence of varying proportions of pleomorphic lipoblasts in a background that resembles undifferentiated pleomorphic sarcoma. It is the rarest liposarcoma variant and usually has an aggressive clinical course.
• pleomorphic rhabdomyosarcoma - an aggressive malignant mesenchymal neoplasm with skeletal muscle differentiation, occurring in adults and rarely in children. The tumor is characterized by the presence of bizarre round, spindle, and polygonal cells. Clinical presentation includes a rapidly enlarging painful mass usually of the lower extremities.
• pleomorphic variant mantle cell lymphoma - an aggressive mantle cell lymphoma characterized by the presence of pleomorphic neoplastic b-lymphocytes.
• pleomorphic xanthoastrocytoma - a who grade ll astrocytic tumor with a relatively favorable prognosis. It is characterized by pleomorphic and lipidized cells expressing gfap often surrounded by a reticulin network and eosinophilic granular bodies. It presents in the superficial cerebral hemispheres and involves the meninges. It typically affects children and young adults.
• pleural malignant mesothelioma - a malignant neoplasm that arises from mesothelial cells in the pleura and shows a diffuse growth pattern. It arises on the parietal and sometimes visceral pleura as multiple small nodules that later become confluent and invade the chest wall adipose tissue and muscle. Asbestos exposure is the main cause for the development of pleural malignant mesothelioma. It usually affects patients over sixty years of age. The latency period is long. Patients usually present with pleural effusion, dyspnea and chest wall pain. Additional signs and symptoms include chills, sweating, weight loss, and weakness. Morphologic variants include epithelioid, desmoplastic, sarcomatoid, and biphasic mesothelioma. The clinical course is usually aggressive.
• pleural well differentiated papillary mesothelioma - a rare, non-invasive, localized or multifocal neoplasm that arises from the pleura. It is characterized by the presence of papillae with myxoid fibrovascular cores, lined by a single layer of mesothelial cells. The clinical course is usually indolent.
• pleuropulmonary blastoma - a malignant neoplasm affecting the lungs and/or the pleura. Pleuropulmonary blastoma is seen in children. Microscopically, the tumor may show features of chondrosarcoma, leiomyosarcoma, rhabdomyosarcoma, liposarcoma, or undifferentiated sarcoma. In approximately 25% of patients with pleuropulmonary blastoma, there are other lesions or neoplasms that may affect patients or their families, including lung or kidney cysts, and ovarian or testicular neoplasms. Heterozygous germline mutations in dicer1 gene have been identified in families harboring pleuropulmonary blastomas.
• plurihormonal pituitary gland adenoma - an infrequent chromophobic or slightly eosinophilic pituitary gland adenoma that shows immunoreactivity for more than one pituitary hormone, excluding the following two combinations: growth hormone/prolactin/tsh, and fsh/lh.
• polycythemia vera - a chronic myeloproliferative neoplasm characterized by an increased red blood cell production. The bone marrow is hypercellular due to a panmyelotic proliferation typically characterized by pleomorphic megakaryocytes. The major symptoms are related to hypertension, splenomegaly or to episodes of thrombosis and/or hemorrhage.
• polycythemia vera, polycythemic phase - polycythemia vera characterized by the proliferation of the erythroid, granulocytic, and megakaryocytic lineages. The peripheral blood shows excess of red blood cells, neutrophilia, and thrombocytosis. The bone marrow is hypercellular for the patient's age.
• polycythemia vera, post-polycythemic myelofibrosis phase - progression of polycythemia vera characterized by decreased erythropoiesis and granulopoiesis, reticulin and collagen fibrosis of the bone marrow, leucoerythroblastic reaction in the peripheral blood, poikilocytosis, tear-drop shaped red blood cells, and splenomegaly.
• polymorphic post-transplant lymphoproliferative disorder - a clonal b-cell lymphoproliferative disorder arising as a result of post-transplant immunosuppression therapy. It is characterized by destructive infiltration of lymph nodes and extranodal sites by a polymorphic b-cell infiltrate composed of small and medium sized lymphocytes, immunoblasts, and plasma cells. In some cases, reduction of the immunosuppression therapy may lead to regression of the lesions. In other cases the lesions may progress to lymphoma.
• polymorphus hemangioendothelioma - an intermediate, rarely metastasizing blood vessel neoplasm. It is characterized by the presence of a polymorphic cellular infiltrate.
• poorly differentiated neuroblastoma - a neuroblastoma in which the differentiating neuroblasts constitute less than five-percent of the tumor cells.
• poorly differentiated prostate adenocarcinoma - an invasive prostate adenocarcinoma characterized by the presence of poorly differentiated malignant cells.
• poorly differentiated thyroid gland carcinoma - an adenocarcinoma arising from the thyroid gland showing only limited evidence of follicular cell differentiation. Microscopically, the adenocarcinoma cells are arranged in insular, solid, and trabecular patterns. There is associated necrosis, and vascular invasion. The prognosis depends on the tumor stage, complete or partial surgical removal of the tumor, and the degree of response to radioactive iodine therapy. (adapted from who tumors of endocrine organs, iarc press, lyon 2004)
• poroma - a benign, well circumscribed sweat gland neoplasm with eccrine or apocrine differentiation. It usually presents as a solitary, dome-shaped papule, nodule, or plaque on acral sites. It is characterized by a proliferation of uniform basaloid cells in the dermis and it is associated with the presence of focal ductal and cystic structures. Complete excision is curative.
• posterior pharyngeal wall squamous cell carcinoma - a squamous cell carcinoma that arises from the posterior wall of the pharynx.
• precancerous polyp - a polyp with severe dysplastic features.
• prefibrotic/early primary myelofibrosis - primary myelofibrosis characterized by bone marrow hypercellularity and the presence of atypical megakaryocytes. There is no increase in the percentage of myeloblasts and no significant increase in reticulin or collagen fibrosis in the bone marrow.
• primary bone osteosarcoma - a usually aggressive malignant bone-forming mesenchymal neoplasm arising from the bone. It usually involves the long bones and predominantly affects adolescents and young adults. Pain and a palpable mass are the most frequent clinical sign and symptom. It may spread to other anatomic sites, particularly the lungs.
• primary central chondrosarcoma - a chondrosarcoma arising from the central portion of bone without a benign precursor.
• primary cutaneous anaplastic large cell lymphoma - an anaplastic large cell lymphoma limited to the skin at the time of diagnosis. Most patients present with solitary or localized skin lesions, which may be tumors, nodules or papules. The t(2;5) translocation that is present in many cases of systemic anaplastic large cell lymphoma, is not found in this disease. (who, 2001)
• primary cutaneous b-cell non-hodgkin lymphoma - a b-cell non-hodgkin lymphoma arising from the skin. Representative examples include cutaneous marginal zone b-cell lymphoma and cutaneous follicle center lymphoma.
• primary cutaneous cd4-positive small/medium t-cell lymphoproliferative disorder - a primary cutaneous t-cell lymphoproliferative disorder. It usually presents with a solitary plaque or tumor on the face, neck, or upper trunk. Morphologically, it is composed of small to medium-sized cd4-positive, cd8-negative, and cd30-negative pleomorphic t-lymphocytes. A small number of large pleomorphic t-lymphocytes may also be present. The lymphocytic infiltrate is dermal. Focal epidermotropism and subcutaneous involvement may be present. The clinical behavior is almost always indolent and most patients present with localized disease.
• primary cutaneous cd8-positive aggressive epidermotropic cytotoxic t-cell lymphoma - an aggressive, epidermotropic primary cutaneous t-cell lymphoma. It is characterized by the presence of eruptive papules and nodules, or tumors, which may be localized or disseminated. Morphologically, it is composed of small to medium-sized, or medium-sized to large, cd8-positive t-lymphocytes with pleomorphic or blastic nuclei. Epidermotropism is often pronounced. Angiocentricity and angioinvasion may be present.
• primary cutaneous diffuse large b-cell lymphoma - a diffuse large b-cell lymphoma that arises from the skin. This category includes primary cutaneous diffuse large b-cell lymphoma, leg type, and primary cutaneous diffuse large b-cell lymphoma, other, which includes primary cutaneous intravascular large b-cell lymphoma and primary cutaneous t-cell/histiocyte-rich large b-cell lymphoma.
• primary cutaneous diffuse large b-cell lymphoma, leg type - an aggressive primary cutaneous b-cell lymphoma, usually involving the lower leg. It is composed of a generally monotonous proliferation of immunoblasts, or less frequently centroblasts, with few admixed reactive cells. This type of lymphoma occurs most often in elderly women who present with rapidly growing tumors, usually on one or both legs. Dissemination to extracutaneous sites is frequent. Treatment with combination chemotherapy is usually required.
• primary cutaneous diffuse large b-cell lymphoma, other - a rare type of primary cutaneous diffuse large b-cell lymphoma that does not belong in the group of primary cutaneous diffuse large b-cell lymphomas, leg type, or the group of primary cutaneous follicle center lymphomas. It includes subtypes/entities of diffuse large b-cell lymphoma (e.G. Intravascular large b-cell lymphoma, plasmablastic lymphoma, t-cell/histiocyte rich lymphoma) that can involve the skin as the primary anatomic site. Such cases, unlike their nodal counterparts, usually have an excellent prognosis.
• primary cutaneous follicle center lymphoma - a primary lymphoma of the skin composed of various numbers of small and large irregular neoplastic follicle center cells. Its morphologic pattern can be nodular, diffuse, or nodular and diffuse. It presents with solitary or grouped plaques and tumors, and it usually involves the scalp, forehead, or trunk. It rarely involves the legs. This type of cutaneous lymphoma tends to remain localized to the skin.
• primary cutaneous gamma-delta t-cell lymphoma - an aggressive cutaneous lymphoma of mature, activated gamma/delta t-lymphocytes. It usually presents with disseminated plaques and nodules. Involvement of mucosal sites is frequent. However, involvement of lymph nodes, spleen, or bone marrow is uncommon. Morphologically, there are three patterns of cutaneous involvement: epidermotropic, dermal, and subcutaneous. Often, more than one pattern may co-exist in a single biopsy specimen, or may be present in different biopsy specimens from the same patient. The lymphocytic infiltrate is composed of medium- to large-sized lymphocytes expressing cd56. Most cases lack both cd4 and cd8, although cd8 may be present in some cases. This group of lymphomas includes cases previously known as subcutaneous panniculitis-like t-cell lymphoma with a gamma/delta phenotype.
• primary cutaneous marginal zone lymphoma of mucosa-associated lymphoid tissue - a low-grade, extranodal marginal zone b-cell lymphoma of the mucosa-associated lymphoid tissue that arises from the skin. It usually presents with multifocal papular or nodular lesions in the arms or trunk. It rarely disseminates to internal organs or progresses to high grade lymphoma.
• primary cutaneous peripheral t-cell lymphoma, rare subtype - a rare, mature t-cell lymphoma arising from the skin.
• primary cutaneous t-cell non-hodgkin lymphoma - a t-cell non-hodgkin lymphoma arising from the skin. Representative examples include mycosis fungoides and primary cutaneous anaplastic large cell lymphoma.
• primary effusion lymphoma - a large b-cell lymphoma usually presenting as a serous effusion without detectable tumor masses. It is universally associated with human herpes virus 8 (hhv8), also called kaposi sarcoma-associated herpesvirus. It mostly occurs in the setting of immunodeficiency. The most common sites of involvement are the pleural, pericardial, and peritoneal cavities. Rare hhv8-positive lymphomas indistinguishable from primary effusion lymphomas (pel) present as solid tumor masses, and have been termed extracavitary pel. The prognosis is extremely unfavorable. (who 2017)
• primary mediastinal (thymic) large b-cell lymphoma - a large b-cell non-hodgkin lymphoma arising in the mediastinum. Morphologically it is characterized by a massive diffuse lymphocytic proliferation associated with compartmentalizing fibrosis. Response to intensive chemotherapy, with or without radiotherapy, is usually good. (who, 2001)
• primary myelofibrosis - a chronic myeloproliferative neoplasm characterized by bone marrow fibrosis, proliferation of atypical megakaryocytes and granulocytes in the bone marrow, anemia, splenomegaly, and extramedullary hematopoiesis. (who, 2001)
• primary peritoneal carcinoma - a rare carcinoma that arises from the peritoneum and resembles the malignant surface epithelial-stromal tumors that arise from the ovary. Serous adenocarcinoma is the most common histologic variant. It affects women almost exclusively. The diagnosis of primary peritoneal carcinoma can be made only if both ovaries are not involved by tumor, or, if the ovaries are involved, the tumor is confined to the ovarian surface without invasion of the ovarian stroma and the peritoneal involvement is greater than the ovarian surface involvement.
• primary peritoneal serous adenocarcinoma - a rare, serous adenocarcinoma that arises from the lining of the peritoneum. It affects females. The clinical behavior and pathologic characteristics are similar to the serous adenocarcinoma that arises from the ovary.
• primary peritoneal serous papillary adenocarcinoma - a rare, serous papillary adenocarcinoma that arises from the lining of the peritoneum. It affects females. The clinical behavior and pathologic characteristics are similar to the serous papillary adenocarcinoma that arises from the ovary.
• primary prostate urothelial carcinoma - an urothelial carcinoma that arises from the urothelial lining of the prostatic ducts or the prostatic urethra.
• prolactin-producing pituitary gland carcinoma - a rare, hormonally functioning or non-functioning pituitary gland adenocarcinoma that produces prolactin.
• prolymphocytic leukemia - a mature b- or t- cell leukemia with progressive clinical course. It is characterized by the presence of medium-sized lymphocytes with visible nucleoli (prolymphocytes) in the peripheral blood, bone marrow, and spleen.
• proneural glioblastoma - a molecular subtype of glioblastoma that is associated with younger age at presentation and is characterized by p53 mutations and pdgfra amplifications.
• prostate acinar adenocarcinoma - an invasive adenocarcinoma of the prostate gland composed of secretory cells. It is the most common histologic type of prostate adenocarcinoma. Several morphologic variants exist, including atrophic, pseudohyperplastic, foamy gland, and oncocytic variants.
• prostate adenocarcinoma - an adenocarcinoma arising from the prostate gland. It is one of the most common malignant tumors afflicting men. The majority of adenocarcinomas arise in the peripheral zone and a minority occurs in the central or the transitional zone of the prostate gland. Grading of prostatic adenocarcinoma predicts disease progression and correlates with survival. Several grading systems have been proposed, of which the gleason system is the most commonly used. Gleason sums of 2 to 4 represent well-differentiated disease, 5 to 7 moderately differentiated disease and 8 to 10 poorly differentiated disease. Prostatic-specific antigen (psa) serum test is widely used as a screening test for the early detection of prostatic adenocarcinoma. Treatment options include radical prostatectomy, radiation therapy, androgen ablation and cryotherapy. Watchful waiting or surveillance alone is an option for older patients with low-grade or low-stage disease.
• prostate adenoid cystic carcinoma - an adenoid cystic carcinoma that arises from the prostate gland.
• prostate adenoma - focal benign glandular hyperplasia in the prostate gland.
• prostate adenosquamous carcinoma - an infrequent invasive carcinoma of the prostate gland characterized by the presence of both glandular and squamous neoplastic components. It is more often located in the transitional zone of the prostate gland and it tends to rapidly metastasize to the bones.
• prostate basal cell carcinoma - an invasive prostate carcinoma composed of prostatic basal cells.
• prostate carcinoma - one of the most common malignant tumors afflicting men. The majority of carcinomas arise in the peripheral zone and a minority occur in the central or the transitional zone of the prostate gland. Grossly, prostatic carcinomas appear as ill-defined yellow areas of discoloration in the prostate gland lobes. Adenocarcinomas represent the overwhelming majority of prostatic carcinomas. Prostatic-specific antigen (psa) serum test is widely used as a screening test for the early detection of prostatic carcinoma. Treatment options include radical prostatectomy, radiation therapy, androgen ablation and cryotherapy. Watchful waiting or surveillance alone is an option for older patients with low-grade or low-stage disease.
• prostate ductal adenocarcinoma - a usually aggressive invasive adenocarcinoma of the prostate gland composed of large glands containing tall columnar cells. The columnar cells have abundant cytoplasm and are reminiscent of endometrial carcinoma. This type of adenocarcinoma has a tendency to metastasize to the lung and penis.
• prostate phyllodes tumor - an unusual, biphasic benign or malignant neoplasm that arises from the prostate gland. It is characterized by the presence of an epithelial glandular component and a proliferating stroma.
• prostate small cell carcinoma - a neuroendocrine carcinoma of the prostate gland with unfavorable prognosis. It is composed of small cells containing neurosecretory granules.
• prostate squamous cell carcinoma - an invasive prostate carcinoma characterized by the presence of malignant cells with squamous differentiation. There is no evidence of glandular differentiation.
• prostate stromal sarcoma - a rare malignant neoplasm arising from specialized prostatic stroma. It is characterized by the presence of stromal overgrowth and hypercellularity, increased number of mitotic figures, and pleomorphism.
• prostate stromal tumor of uncertain malignant potential - a neoplastic lesion that arises from the prostate gland stroma. Morphologic characteristics include hypercellular stroma with scattered atypical cells, prominent overgrowth of the prostatic stroma, or changes resembling benign phyllodes tumor. The majority of cases do not have an aggressive clinical course. A minority of cases however, may progress to stromal sarcoma.
• prostate undifferentiated carcinoma - an invasive prostate carcinoma characterized by the presence of undifferentiated malignant cells.
• protoplasmic astrocytoma - a rare variant of diffuse astrocytoma. It is predominantly composed of neoplastic astrocytes showing a small cell body with few, flaccid processes with a low content of glial filaments and scant gfap expression. This lesion is not well defined and is considered by some authors as an occasional histopathological feature rather than a reproducibly identifiable variant. When occurring in children, this neoplasm may be difficult to separate from pilocytic juvenile astrocytoma. (adapted from who)
• proximal urethral carcinoma - a carcinoma that arises from the proximal part of the urethra.
• psammomatous meningioma - a who grade I meningioma characterized by the presence of psammoma bodies that predominate over the meningeal cells.
• pseudomyogenic hemangioendothelioma - an intermediate, rarely metastasizing blood vessel neoplasm that more frequently affects young adult males and usually arises in the lower limbs. In approximately half of the affected patients the tumor is painful and in two-thirds of the patients the tumor is multifocal. Morphologically it is characterized by the presence of sheets and fascicles of spindle cells with abundant eosinophilic cytoplasm and vesicular nuclei. Cytologic atypia is usually mild. Approximately 60% of the patients develop local recurrences or additional tumors in the same anatomic region.
• pulmonary artery choriocarcinoma - a rare choriocarcinoma that arises from a pulmonary artery.
• pulmonary blastoma - a biphasic tumor that consists of fetal adenocarcinoma (typically low-grade) and primitive mesenchymal stroma. Foci of specific mesenchymal differentiation (osteosarcoma, chondrosarcoma, or rhabdomyosarcoma) may also be present, but are not required for the diagnosis. Most patients are smokers. The prognosis is very poor. (who 2015)
• radiation-related angiosarcoma - a malignant vascular neoplasm arising in an anatomic site exposed to radiation therapy.
• radiation-related osteosarcoma - a high grade osteosarcoma arising in an irradiated bone.
• rectal adenocarcinoma - an adenocarcinoma arising from the rectum. It is more frequently seen in populations with a western type diet and in patients with a history of chronic inflammatory bowel disease. Signs and symptoms include intestinal bleeding, anemia, and change in bowel habits. According to the degree of cellular differentiation, rectal adenocarcinomas are divided into well, moderately, and poorly differentiated. Histologic variants include mucinous adenocarcinoma, signet ring cell carcinoma, medullary carcinoma, serrated adenocarcinoma, cribriform comedo-type adenocarcinoma, and micropapillary adenocarcinoma.
• rectal adenoma - an adenoma that arises from the rectum. The group of rectal adenomas includes tubular, villous, and tubulovillous adenomas, traditional serrated adenomas, sessile serrated adenomas/polyps, and familial adenomatous polyposis.
• rectal adenoma with severe dysplasia - an adenoma that arises from the rectum. It is characterized by the presence of severe epithelial dysplasia.
• rectal adenomatous polyp - a polypoid adenoma that arises from and protrudes into the lumen of the rectum. Epithelial dysplasia is always present. According to the architectural pattern it is classified as tubular, tubulovillous, or villous.
• rectal adenosquamous carcinoma - an unusual rectal carcinoma characterized by the presence of glandular and squamous carcinomatous components. The two carcinomatous components may be admixed within the tumor, or the two may appear separately in different areas.
• rectal carcinoma - a malignant epithelial neoplasm that arises from the rectum and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas.
• rectal medullary carcinoma - a rare, invasive rectal adenocarcinoma characterized by the presence of sheets of malignant epithelial cells with vesicular nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm. It usually has a favorable prognosis.
• rectal mucinous adenocarcinoma - an invasive adenocarcinoma of the rectum characterized by the presence of pools of extracellular mucin. Malignant glandular epithelial cells are present in the mucin collections. Mucin constitutes more than 50% of the lesion.
• rectal serrated adenocarcinoma - a rare, invasive rectal adenocarcinoma characterized by the presence of a malignant infiltrate with serrated glandular architecture.
• rectal serrated lesions and polyps - polyps that arises from the rectum. They are characterized by the presence of serrated glands and the absence of generalized dysplasia.
• rectal signet ring cell adenocarcinoma - an infiltrating adenocarcinoma arising from the rectum. It is characterized by the presence of malignant glandular cells with prominent intracytoplasmic mucin. These cells constitute more than 50% of the malignant cellular population.
• rectal small cell carcinoma - an aggressive, high-grade, and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the rectum. It is characterized by the presence of malignant small cells.
• rectal squamous cell carcinoma - a very rare rectal carcinoma characterized by the presence of a malignant squamous cell infiltrate.
• rectal traditional serrated adenoma - an adenoma that arises from the rectum. It is characterized by prominent serration of the glands.
• rectal tubular adenoma - a usually polypoid neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by a tubular architectural pattern. The neoplastic glandular cells have dysplastic features.
• rectal tubulovillous adenoma - a neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by tubular and villous architectural patterns. The neoplastic glandular cells have dysplastic features.
• rectal undifferentiated carcinoma - an invasive malignant epithelial tumor that arises from the rectum. There is no morphologic, immunophenotypic, or molecular biological evidence of glandular or squamous differentiation.
• rectal villous adenoma - a neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by a villous architectural pattern. The neoplastic glandular cells have dysplastic features.
• rectosigmoid adenocarcinoma - an adenocarcinoma arising from the rectosigmoid area. It is more frequently seen in populations with a western type diet and in patients with a history of chronic inflammatory bowel disease. Signs and symptoms include intestinal bleeding, anemia, and change in bowel habits. According to the degree of cellular differentiation, rectosigmoid adenocarcinomas are divided into well, moderately, and poorly differentiated. Histologic variants include mucinous adenocarcinoma, signet ring cell carcinoma, medullary carcinoma, serrated adenocarcinoma, cribriform comedo-type adenocarcinoma, and micropapillary adenocarcinoma.
• rectosigmoid carcinoma - a malignant epithelial neoplasm that arises from the rectosigmoid area and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas. About 50% of colorectal carcinomas occur in the rectosigmoid area.
• rectosigmoid mucinous adenocarcinoma - an invasive adenocarcinoma of the rectosigmoid area characterized by the presence of pools of extracellular mucin. Malignant glandular epithelial cells are present in the mucin collections. Mucin constitutes more than 50% of the lesion.
• rectosigmoid signet ring cell carcinoma - an infiltrating adenocarcinoma arising from the rectosigmoid area. It is characterized by the presence of malignant glandular cells with prominent intracytoplasmic mucin. These cells constitute more than 50% of the malignant cellular population.
• refractory anemia - a myelodysplastic syndrome characterized mainly by dysplasia of the erythroid series. Refractory anemia is uncommon. It is primarily a disease of older adults. The median survival exceeds 5 years. (who, 2001)
• refractory cytopenia of childhood - the most common subtype of the myelodysplastic syndromes affecting children. It is characterized by persistent cytopenia with less than 5% blasts in the bone marrow and less than 2% blasts in the peripheral blood.
• refractory neutropenia - a myelodysplastic syndrome characterized by the presence of at least 10% dysplastic neutrophils in the bone marrow or the peripheral blood.
• refractory thrombocytopenia - a myelodysplastic syndrome characterized by the presence of at least 10% dysplastic megakaryocytes, found within at least 30 megakaryocytes examined in the bone marrow.
• renal cell carcinoma - a carcinoma arising from the renal parenchyma. There is a strong correlation between cigarette smoking and the development of renal cell carcinoma. The clinical presentation includes : hematuria, flank pain and a palpable lumbar mass. A high percentage of renal cell carcinomas are diagnosed when an ultrasound is performed for other purposes. Radical nephrectomy is the standard intervention procedure. Renal cell carcinoma is generally considered to be resistant to radiation treatment and chemotherapy.
• renal cell carcinoma associated with xp11.2 translocations/tfe3 gene fusions - a group of renal cell carcinomas characterized by the presence of different translocations involving the chromosome xp11.2. These translocations result in the creation of gene fusions involving the tfe3 gene. Patients are usually children and young adults. Morphologically, the malignant epithelial cells form papillary patterns.
• renal cell carcinoma associated with inv(x)(p11;q12) - a renal cell carcinoma with papillary architecture comprised of clear cells. It is characterized by the inv(x)(p11;q12) resulting in fusion of the nono (p54nrb) and tfe3 genes.
• renal cell carcinoma associated with t(x;1)(p11.2;p34) - a renal cell carcinoma with papillary architecture comprised of clear cells. It is characterized by the t(x;1)(p11.2;p34) resulting in fusion of the psf and tfe3 genes.
• renal cell carcinoma associated with t(x;1)(p11.2;q21) - a renal cell carcinoma with papillary architecture comprised of clear cells. It is characterized by the t(x;1)(p11.2;q21) resulting in fusion of the prcc and tfe3 genes.
• renal cell carcinoma associated with t(x;17)(p11.2;q25) - a renal cell carcinoma with papillary architecture comprised of clear cells. It is characterized by the t(x;1)(p11.2;q25) resulting in fusion of the aspl and tfe3 genes.
• renal pelvis carcinoma - a carcinoma arising in the renal pelvis. The majority of renal pelvis carcinomas are transitional cell and less frequently squamous cell carcinomas.
• renal pelvis papillary urothelial carcinoma - a papillary transitional cell carcinoma that arises from the renal pelvis.
• renal pelvis urothelial carcinoma - a carcinoma that arises from the transitional epithelium of the renal pelvis. It is associated with tobacco use and usually presents with gross or microscopic hematuria. Urothelial carcinomas of the renal pelvis are usually of higher grade and higher stage compared to bladder urothelial carcinomas.
• retiform hemangioendothelioma - an intermediate, locally aggressive and rarely metastasizing blood vessel neoplasm. It is characterized by the presence of hobnail endothelial cells and formation of arborizing vascular channels.
• retinoblastoma - a malignant tumor that originates in the nuclear layer of the retina. As the most common primary tumor of the eye in children, retinoblastoma is still relatively uncommon, accounting for only 1% of all malignant tumors in pediatric patients. Approximately 95% of cases are diagnosed before age 5. These tumors may be multifocal, bilateral, congenital, inherited, or acquired. Seventy-five percent of retinoblastomas are unilateral; 60% occur sporadically. A predisposition to retinoblastoma has been associated with 13q14 cytogenetic abnormalities. Patients with the inherited form also appear to be at increased risk for secondary nonocular malignancies such as osteosarcoma, malignant fibrous histiocytoma, and fibrosarcoma.
• retinocytoma - a rare, unilateral or bilateral benign neoplasm that arises from the retina. There is an increased risk of malignant transformation to retinoblastoma; therefore, patients with a diagnosis of retinocytoma should be closely observed.
• retromolar trigone squamous cell carcinoma - a squamous cell carcinoma that arises from the retromolar trigone. Pain, often radiating to the ear, is the presenting symptom. The prognosis is poor.
• retroperitoneal carcinoma - a rare carcinoma that arises from the retroperitoneal space.
• rhabdoid meningioma - a who grade iii meningioma characterized by the predominant presence of rhabdoid cells forming sheets.
• rhabdoid tumor - an aggressive malignant embryonal neoplasm usually occurring during childhood. It is characterized by the presence of large cells with abundant cytoplasm, large eccentric nucleus, and a prominent nucleolus and it is associated with abnormalities of chromosome 22. It can arise from the central nervous system, kidney, and the soft tissues. The prognosis is poor.
• rhabdoid tumor of the kidney - a rhabdoid tumor that arises from the kidney. It occurs in children and it is associated with abnormalities of chromosome 22. It is characterized by the presence of cells with a large eccentric nucleus, prominent nucleolus, and abundant cytoplasm. The prognosis is poor.
• rhabdomyoma - a benign mesenchymal tumor arising from skeletal or cardiac muscle.
• rhabdomyosarcoma - a rare aggressive malignant mesenchymal neoplasm arising from skeletal muscle. It usually occurs in children and young adults. Only a small percentage of tumors arise in the skeletal muscle of the extremities. The majority arise in other anatomic sites.
• rhabdomyosarcoma with mixed embryonal and alveolar features - a rhabdomyosarcoma composed of embryonic and alveolar components. It is characterized by the presence of spindle cells with myoblastic differentiation, a myxoid stroma, and fibrous septa. These tumors were previously considered variants of alveolar rhabdomyosarcoma. The lack of pax3-foxo1 fusions in most of these tumors suggests that are biologically and clinically related to embryonal rhabdomyosarcoma.
• rosette-forming glioneuronal tumor of the fourth ventricle - a central nervous system neoplasm arising from the fourth ventricle. It is characterized by the presence of neurocytes forming pseudorosettes and astrocytes which contain rosenthal fibers. Cytologic atypia is minimal.
• salivary gland adenocarcinoma - an adenocarcinoma arising from the salivary gland. It includes the salivary gland polymorphous low grade adenocarcinoma, salivary gland oncocytic carcinoma, salivary gland mucinous adenocarcinoma, salivary gland low grade cribriform cystadenocarcinoma, salivary gland cystadenocarcinoma, salivary gland basal cell adenocarcinoma, salivary gland acinic cell carcinoma, salivary duct carcinoma, and salivary gland adenocarcinoma not otherwise specified.
• salivary gland adenoid cystic carcinoma - an adenoid cystic carcinoma arising from the salivary gland. It is characterized by the presence of epithelial and myoepithelial cells forming tubular, cribriform, and solid patterns. It usually presents as a slow growing mass. Patients may experience pain because of the tumor propensity for perineural invasion. The tumor may follow an aggressive clinical course with recurrences and mestastases to distant sites including lungs, bones, brain, and liver.
• salivary gland adenosquamous carcinoma - a rare, aggressive carcinoma that arises from the salivary glands. It is characterized by the presence of a squamous and a glandular epithelial component.
• salivary gland carcinoma - a carcinoma that arises from the major or minor salivary glands. Representative examples include carcinoma ex pleomorphic adenoma, adenocarcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma.
• salivary gland carcinoma ex pleomorphic adenoma - a carcinoma that arises from a pleomorphic adenoma in the salivary glands. It usually originates in the parotid gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.
• salivary gland clear cell carcinoma - a carcinoma that arises from the salivary glands, most often the minor salivary glands. It is characterized by the presence of a monomorphic population of malignant epithelial cells with clear cytoplasm and the absence of morphologic features that define other primary neoplasms of the salivary glands.
• salivary gland epithelial-myoepithelial carcinoma - a carcinoma that arises from the salivary glands, most often the parotid gland. It presents as a slow growing and painless mass. It is characterized by the presence of duct-like structures lined by two layers of cells, an inner layer composed of epithelial-type cells and an outer layer composed of clear, myoepithelial-type cells.
• salivary gland lymphoepithelial carcinoma - a rare carcinoma that arises from the salivary glands, most often the parotid gland. It is characterized by the presence of an undifferentiated carcinomatous component associated with a prominent reactive lymphoplasmacytic infiltrate.
• salivary gland monomorphic adenoma - a benign epithelial neoplasm arising from the salivary glands. It is characterized by the presence of a monomorphic cellular infiltrate.
• salivary gland mucoepidermoid carcinoma - a carcinoma that arises from the salivary glands. It is the most common primary carcinoma of the salivary glands and usually presents as a firm and painless mass. It is characterized by the presence of squamous cells, mucus producing cells, and cells of intermediate type. The majority of cases have a favorable outcome.
• salivary gland myoepithelial carcinoma - a locally aggressive carcinoma that arises from the salivary glands, predominantly the parotid gland. It is characterized by the presence of a malignant cellular infiltrate exhibiting myoepithelial differentiation. Patients usually present with a painless mass.
• salivary gland pleomorphic adenoma - a benign, slow-growing tumor composed of cells that demonstrate both epithelial and mesenchymal differentiation. It is the most common neoplasm of salivary gland origin, and mostly occurs in the parotid gland. The average age of patients has been reported to be 43 years; women are more often affected than men. The malignant change rate has been estimated to be 6%. The malignant counterpart is carcinoma ex pleomorphic adenoma.
• salivary gland small cell neuroendocrine carcinoma - an infrequent small cell carcinoma that arises from the salivary glands. It is characterized by the presence of neuroendocrine differentiation and a high number of mitotic figures.
• salivary gland squamous cell carcinoma - a squamous cell carcinoma arising from the salivary glands. The majority of patients are in their sixth through eight decades. It usually presents as a rapidly enlarging mass, which may be painful. It usually has an aggressive clinical course.
• salivary gland undifferentiated carcinoma - a salivary gland carcinoma characterized by the presence of undifferentiated, anaplastic malignant epithelial cells.
• sarcoma - a usually aggressive malignant neoplasm of the soft tissue or bone. It arises from muscle, fat, fibrous tissue, bone, cartilage, and blood vessels. Sarcomas occur in both children and adults. The prognosis depends largely on the degree of differentiation (grade) of the neoplasm. Representative subtypes are liposarcoma, leiomyosarcoma, osteosarcoma, and chondrosarcoma.
• sarcomatoid carcinoma - a malignant epithelial neoplasm characterized by the presence of spindle cells and anaplastic morphologic features. Giant cells and a sarcomatous component may also be present.
• sarcomatoid mesothelioma - a malignant neoplasm arising from mesothelial cells. It is characterized by the presence of spindle cells. Anaplastic morphologic features and multinucleated malignant cells may also be seen.
• sarcomatoid renal cell carcinoma - a high grade carcinoma of the kidney. It is not a distinct clinicopathological entity and includes a diverse group of renal cell carcinomas which have been transformed from a lower to a higher grade.
• schwannoma - a benign, usually encapsulated slow growing tumor composed of schwann cells. It affects peripheral and cranial nerves. It recurs infrequently and only rare cases associated with malignant transformation have been reported.
• sclerosing rhabdomyosarcoma - an uncommon variant of rhabdomyosarcoma with sclerosing morphology. It usually arises from the limbs.
• sebaceous adenoma - a benign, well circumscribed neoplasm arising from the sebaceous glands. It usually presents as a small yellowish tumor in the sun exposed skin of head and neck. It is characterized by the presence of sebaceous cells aggregates with a peripheral rim of basaloid cells.
• sebaceous carcinoma - an adenocarcinoma with sebaceous differentiation. It presents as a painless mass and it may be multifocal. It grows in the ocular adnexae and in the skin of head and neck, trunk, genitals, and extremities. It is characterized by the presence of malignant cells with multivesicular and clear cytoplasm. It may recur and metastasize.
• secondary acute myeloid leukemia - an acute myeloid leukemia arising from prior myelodysplastic syndrome, myeloproliferative neoplasm, or myelodysplastic/myeloproliferative neoplasm, or as a result of previous exposure to alkylating agents or topoisomerase ii inhibitors.
• secondary chondrosarcoma - a chondrosarcoma that arises either in a pre-existing enchondroma or close to the cartilaginous cap of a pre-existing osteochondroma.
• secondary glioblastoma - a glioblastoma arising from a lower grade astrocytoma. It is more commonly seen in younger patients and is usually associated with idh1 or idh2 gene mutations.
• secondary osteosarcoma - an osteosarcoma arising from a pre-existing lesion of the bone, usually paget disease, or due to radiation therapy.
• secretory meningioma - a who grade I meningioma characterized by the presence of epithelial differentiation and numerous intracellular pas positive bodies that are rich in glycogen.
• seminoma - a radiosensitive malignant germ cell tumor found in the testis (especially undescended), and extragonadal sites (anterior mediastinum and pineal gland). It is characterized by the presence of uniform cells with clear or dense cytoplasm which contains glycogen, and by a large nucleus which contains one or more nucleoli. The neoplastic germ cells form aggregates separated by fibrous septa. The fibrous septa contain chronic inflammatory cells, mainly lymphocytes.
• serous adenocarcinoma - an adenocarcinoma that is characterized by the presence of papillary patterns and cellular budding. Psammoma bodies may be present. Representative examples include cervical serous adenocarcinoma, endometrial serous adenocarcinoma, ovarian serous adenocarcinoma, and primary peritoneal serous adenocarcinoma.
• serous endometrial intraepithelial carcinoma - a precursor of endometrial serous adenocarcinoma characterized by the replacement of the normal endometrial cells by malignant glandular cells that resemble the malignant cells of invasive serous adenocarcinoma. The endometrial neoplastic process is non-invasive. It may coexist with invasive endometrial adenocarcinoma or can be associated with metastases outside the uterus, in the absence of invasive endometrial carcinoma.
• sezary syndrome - a generalized peripheral (mature) t-cell neoplasm characterized by the presence of erythroderma, lymphadenopathy, and neoplastic, cerebriform t-lymphocytes in the blood. Sezary syndrome is an aggressive disease. (who, 2001)
• signet ring cell carcinoma - a usually aggressive, poorly differentiated invasive adenocarcinoma characterized by the presence of malignant glandular cells in which the nucleus is pressed to one side by the presence of intracytoplasmic mucus. It may arise from the stomach, small and large intestine, ampulla of vater, appendix, gallbladder, pancreas, lung, bladder, breast, and prostate gland.
• sinonasal squamous cell carcinoma - a rare, keratinizing or non-keratinizing squamous cell carcinoma arising from the mucosal epithelium of the nasal cavity or the paranasal sinuses. It affects most often the maxillary sinus. Less frequently, it arises from the nasal cavity, ethmoid sinus, sphenoid sinus, and frontal sinus. Symptoms include nasal fullness, epistaxis, rhinorhea, pain, and paresthesia. Patients with nasal squamous cell carcinoma usually present earlier than patients with maxillary sinus carcinoma and have a better prognosis compared to the latter group.
• skin adenosquamous carcinoma - an uncommon carcinoma that arises from the skin. It is characterized by the presence of malignant glandular and malignant squamous cellular components.
• skin angiosarcoma - a malignant vascular neoplasm arising from the skin.
• skin basal cell carcinoma - the most frequently seen skin cancer. It arises from basal cells of the epidermis and pilosebaceous units. Clinically it is divided into the following types: nodular, ulcerative, superficial, multicentric, erythematous, and sclerosing or morphea-like. More than 95% of these carcinomas occur in patients over 40. They develop on hair-bearing skin, most commonly on sun-exposed areas. Approximately 85% are found on the head and neck and the remaining 15% on the trunk and extremities. Basal cell carcinoma usually grows in a slow and indolent fashion. However, if untreated, the tumor may invade the subcutaneous fat, skeletal muscle and bone. Distant metastases are rare. Excision, curettage and irradiation cure most basal cell carcinomas.
• skin carcinoma - a carcinoma that arises from the skin. Representative examples are basal cell carcinoma and squamous cell carcinoma.
• skin fibrous histiocytoma - a solitary, slowly growing, nodular tumor most often affecting the extremities. It is composed of fibrous and histiocytic cells which infiltrate the dermis and occasionally the underlying subcutaneous tissue. Usually local excision is curative. Recurrences are reported only in a small minority of cases.
• skin hemangioma - a hemangioma arising from the skin.
• skin lymphangioma - a lymphangioma arising from the skin.
• skin papilloma - a benign papillary neoplastic growth on the skin composed of epithelial cells and a fibrous stalk. It usually develops in the eyelid, axilla, neck, upper chest, and groin.
• skin squamous cell carcinoma - a carcinoma arising from the squamous cells of the epidermis. Skin squamous cell carcinoma is most commonly found on sun-exposed areas. The majority of the tumors are well-differentiated.
• skull base chordoma - a slow-growing malignant bone tumor arising from the remnants of the notochord and occurring in the base of the skull. It is characterized by a lobulated growth pattern, myxoid stroma formation, and the presence of physaliphorous cells..
• small cell carcinoma - a neuroendocrine carcinoma composed of small malignant cells which are often said to resemble "Oat cells" under the microscope. Small cell carcinoma most often affects the lungs. Clinically, this is often a rapidly growing cancer that spreads to distant sites early.
• small cell glioblastoma - a morphologic variant of glioblastoma characterized by the presence of a highly proliferative and monotonous population of malignant small glial cells.
• small cell variant anaplastic large cell lymphoma - a histologic variant of anaplastic large cell lymphoma characterized by the presence of a predominant population of small to medium size malignant cells with irregular nuclei.
• small intestinal adenocarcinoma - an adenocarcinoma that arises from the small intestine. Histologic variants include mucinous adenocarcinoma and signet ring cell carcinoma.
• small intestinal carcinoma - a carcinoma arising from the small intestine. The vast majority are adenocarcinomas. The remaining cases are adenosquamous, squamous, or undifferentiated carcinomas.
• small intestinal medullary carcinoma - a carcinoma that arises from the small intestine. It is characterized by the presence of malignant epithelial cells with vesicular nucleus, distinct nucleolus, and abundant pink cytoplasm.
• small intestinal mucinous adenocarcinoma - an invasive adenocarcinoma that arises from the small intestine. It is composed of malignant glandular cells which contain intracytoplasmic mucin. Often, the infiltrating glandular structures are associated with mucoid stromal formation.
• small intestinal signet ring cell carcinoma - an invasive adenocarcinoma that arises from the small intestine. It is characterized by the presence of malignant glandular cells in which the nucleus is pressed to one side by the presence of intracytoplasmic mucus.
• small intestinal small cell carcinoma - an aggressive, high-grade, and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the small intestine. It is characterized by the presence of malignant small cells.
• small lymphocytic lymphoma - a non-hodgkin lymphoma composed of monomorphic small, round b-lymphocytes in the lymph nodes. When the lymphoid process predominantly involves the bone marrow and the peripheral blood it is called chronic lymphocytic leukemia. (who, 2001)
• small lymphocytic lymphoma with immunoglobulin heavy chain variable-region gene somatic hypermutation - small lymphocytic lymphoma characterized by the presence of somatic hypermutation within the immunoglobulin heavy chain gene variable region of neoplastic clones. Patients have a better prognosis as compared to those with unmutated immunoglobulin heavy chain gene variable region rearrangements.
• small lymphocytic lymphoma with plasmacytoid differentiation - a small lymphocytic lymphoma characterized by the presence of neoplastic lymphocytes with plasmacytoid morphology.
• small lymphocytic lymphoma with unmutated immunoglobulin heavy chain variable-region gene - small lymphocytic lymphoma characterized by the absence of somatic hypermutation within the immunoglobulin heavy chain gene variable region of neoplastic clones. Patients have a significantly worse prognosis as compared to those with mutated immunoglobulin heavy chain gene variable region rearrangements.
• smoldering plasma cell myeloma - a plasma cell myeloma lacking clinical manifestations and organ impairment.
• solid lung adenocarcinoma - a morphologic variant of lung adenocarcinoma characterized by the presence of polygonal malignant cells forming sheets. Acinar, papillary, micropapillary, or lepidic growth patterns are absent. If the tumor is 100 percent solid, intracellular mucin should be present in at least five tumor cells in each of two high-power fields and confirmed with mucin immunohistochemical stains. Tumors formerly classified as large cell carcinomas expressing pneumocyte immunohistochemical markers, even if intracellular mucin is absent, are now included in this category.
• solitary circumscribed neuroma - a benign peripheral nerve sheath tumor characterized by the presence of schwann cells, axons, and perineurial fibroblasts. It usually arises from the skin of the head and neck or the oral mucosa. It presents as a solitary and painless nodular mass.
• solitary fibrous tumor - a localized neoplasm of probable fibroblastic derivation. It is characterized by the presence of round to spindle-shaped cells, hylanized stroma formation, thin-walled branching blood vessels, and thin bands of collagen.
• solitary plasmacytoma - a localized clonal (malignant) plasma cell infiltrate either in the bony skeleton or soft tissue without peripheral blood involvement.
• solitary plasmacytoma of bone - a localized, clonal (malignant) plasma cell infiltrate in the bone, without peripheral blood involvement. The most commonly affected bones are the vertebrae, ribs, skull, pelvis and femur. X-rays examination reveals a solitary lytic lesion.
• somatotroph adenoma - an adenoma of the anterior lobe of the pituitary gland that produces growth hormone. The vast majority of cases are hormonally functioning and are associated with either gigantism or acromegaly.
• spinal cord neoplasm - a primary or metastatic neoplasm affecting the spinal cord.
• spindle cell melanoma - a melanoma characterized by the presence of malignant spindle-shaped melanocytes.
• spindle cell rhabdomyosarcoma - an uncommon variant of rhabdomyosarcoma characterized by the presence of whorls of spindle cells forming a storiform pattern. In children it usually arises in the paratesticular region. In adults it usually arises from the deep soft tissues in the head and neck.
• spindle cell/sclerosing rhabdomyosarcoma - an uncommon variant of rhabdomyosarcoma with spindle cell or sclerosing morphology. It affects both children and adults and it is more common in males.
• spiradenocarcinoma - a very rare, aggressive carcinoma of the sweat glands arising from malignant transformation of a long standing spiradenoma. It usually grows in the upper extremities, lower extremities, trunk, and head and neck. It has the tendency to recur and metastasize most often to the lymph nodes, bones, and lungs.
• spiradenoma - a benign epithelial neoplasm with eccrine or apocrine differentiation, arising from the sweat glands. It usually presents as a solitary, well circumscribed, firm nodule in the face and upper trunk. It is characterized by the presence of basaloid cells forming nodules in the dermis. Cases of carcinoma arising from long standing spiradenomas have been reported.
• spitz nevus - a benign, acquired or congenital, usually single skin lesion. It can occur on any area of the body, but most commonly occurs on the face of children and the thighs of young females. It is characterized by a proliferation of large spindle, oval, or large epithelioid melanocytes in the dermal-epidermal junction. The melanocytic proliferation subsequently extends into the dermis.
• splenic b-cell lymphoma/leukemia, unclassifiable - a small b-cell clonal lymphoproliferative disorder of the spleen that does not fall into any of the other categories of mature b-cell neoplasms.
• splenic diffuse red pulp small b-cell lymphoma - an uncommon, indolent b-cell non-hodgkin lymphoma composed of small b-lymphocytes involving the red pulp of the spleen, bone marrow, and peripheral blood. Patients often have massive splenomegaly. The peripheral blood examination reveals villous lymphocytes.
• splenic marginal zone lymphoma - a b-cell non-hodgkin lymphoma composed of small lymphocytes which surround and replace the splenic white pulp germinal centers. It involves the spleen and splenic hilar lymph nodes, bone marrow, and often the peripheral blood. When lymphoma cells are present in the peripheral blood, they are usually, but not always, characterized by the presence of short polar villi. (who)
• sporadic breast carcinoma - a carcinoma that arises from the breast and is not caused by inherited genetic mutations.
• sporadic gastric diffuse adenocarcinoma - a sporadic adenocarcinoma that arises from the gastric mucosa and is characterized by the presence of poorly cohesive malignant cells and absence of glandular formations.
• sporadic papillary renal cell carcinoma - a papillary renal cell carcinoma that occurs in a patient who does not have a family history of papillary renal cell carcinoma nor is a carrier of an inherited dna change that would increase the risk of developing this carcinoma.
• sporadic retinoblastoma - a retinoblastoma that occurs in a patient without a family history of the disease.
• sporadic thyroid gland medullary carcinoma - a non-hereditary medullary carcinoma of the thyroid gland not associated with multiple endocrine neoplasia. The majority of thyroid gland medullary carcinomas are sporadic.
• squamous cell carcinoma - a carcinoma arising from squamous epithelial cells. Morphologically, it is characterized by the proliferation of atypical, often pleomorphic squamous cells. Squamous cell carcinomas are graded by the degree of cellular differentiation as well, moderately, or poorly differentiated. Well differentiated carcinomas are usually associated with keratin production and the presence of intercellular bridges between adjacent cells. Representative examples are lung squamous cell carcinoma, skin squamous cell carcinoma, and cervical squamous cell carcinoma.
• squamous cell carcinoma of the penis - a squamous cell carcinoma arising from the penis. It occurs chiefly in the squamous epithelium of the glans, coronal sulcus, and foreskin. Etiologic factors include phimosis, lichen sclerosus, smoking, ultraviolet irradiation, history of warts or condylomas, and lack of circumcision. Human papilloma virus is present in a subset of penile squamous cell carcinomas. Patients may present with an exophytic or flat ulcerative mass in the glans or a large primary tumor with inguinal nodal and skin metastases. (who, 2004)
• squamous cell papilloma - a benign epithelial neoplasm characterized by a papillary growth pattern and a proliferation of neoplastic squamous cells without morphologic evidence of malignancy. Most frequently it arises in the oral cavity, nasopharynx, larynx, esophagus, vagina, and vulva.
• stage 0 ampulla of vater cancer ajcc v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (from ajcc 7th ed.)
• stage 0 anal canal cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 appendix carcinoma ajcc v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial or invasion of lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stage 0 bladder urothelial carcinoma ajcc v6 and v7 - stage 0 includes: 0a (ta, n0, m0); 0is (tis, n0, m0). Ta: noninvasive papillary carcinoma. Tis: carcinoma in situ: "Flat tumor". N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 cervical cancer ajcc v7 - stage 0 includes: (tis, n0, m0). Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. Figo no longer includes stage 0. (ajcc 7th ed.)
• stage 0 colon cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial or invasion of lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 colorectal cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial or invasion of the lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 esophageal adenocarcinoma ajcc v7 - stage 0 includes: tis (hgd), n0, m0, g1,gx. Tis: high-grade dysplasia. N0: no regional lymph node metastasis. M0: no distant metastasis. G1: well differentiated. Gx: grade cannot be assessed-stage grouping as g1. (ajcc 7th ed.)
• stage 0 esophageal cancer ajcc v7 - stage 0 includes: for squamous cell carcinoma: tis (hgd), n0, m0, g1, gx, tumor location: any. For adenocarcinoma: tis (hgd), n0, m0, g1, gx. Tis: high-grade dysplasia. N0: no regional lymph node metastasis. M0: no distant metastasis. G1: well differentiated. Gx: grade cannot be assessed-stage grouping as g1. Tumor location: location of the primary cancer site is defined by the position of the upper (proximal) edge of the tumor in the esophagus. (ajcc 7th ed.)
• stage 0 esophageal squamous cell carcinoma ajcc v7 - stage 0 includes: tis (hgd), n0, m0, g1, gx, tumor location: any. Tis: high-grade dysplasia. N0: no regional lymph node metastasis. M0: no distant metastasis. G1: well differentiated. Gx: grade cannot be assessed-stage grouping as g1. Tumor location: location of the primary cancer site is defined by the position of the upper (proximal) edge of the tumor in the esophagus. (ajcc 7th ed.)
• stage 0 gallbladder cancer ajcc v6 and v7 - stage 0 includes: (tis, n0, m0). Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 gastric cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial tumor without invasion of the lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 lung cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 pancreatic cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 rectal cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial or invasion of the lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 rectosigmoid cancer ajcc v6 and v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ: intraepithelial or invasion of the lamina propria. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0 renal pelvis cancer ajcc v7 - stage 0 includes: 0a (ta, n0, m0); 0is (tis, n0, m0). Ta: papillary noninvasive carcinoma. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stage 0 small intestinal cancer ajcc v7 - stage 0 includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stage 0 squamous cell carcinoma - a malignant epithelial neoplasm confined to the squamous epithelium, without invasion of the underlying tissues.
• stage 0 transitional cell carcinoma - a lesion in which the surface epithelium of the bladder or the renal pelvis and ureter contains transitional cells which display malignant cytologic characteristics. There is no evidence of stromal invasion.
• stage 0 ureter cancer ajcc v7 - stage 0 includes: 0a (ta, n0, m0); 0is (tis, n0, m0). Ta: papillary noninvasive carcinoma. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stage 0a bladder urothelial carcinoma ajcc v6 and v7 - stage 0a includes: ta, n0, m0. Ta: papillary noninvasive carcinoma. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0a renal pelvis cancer ajcc v7 - stage 0a includes: ta, n0, m0. Ta: papillary noninvasive carcinoma. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stage 0is bladder urothelial carcinoma ajcc v6 and v7 - stage 0is includes: tis, n0, m0. Tis: carcinoma in situ: "Flat tumor". N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 6th and 7th eds.)
• stage 0is renal pelvis cancer ajcc v7 - stage 0is includes: tis, n0, m0. Tis: carcinoma in situ. N0: no regional lymph node metastasis. M0: no distant metastasis. (ajcc 7th ed.)
• stromal predominant kidney wilms tumor - wilms tumor of the kidney characterized by the predominance of the mesenchymal component.
• subcutaneous panniculitis-like t-cell lymphoma - a cytotoxic primary cutaneous t-cell lymphoma. Recent studies suggest there are at least two groups of subcutaneous panniculitis-like t-cell lymphomas, each with distinct histologic features, immunophenotypic profile, and prognosis. One group has an alpha/beta, cd8 positive phenotype, involves only subcutaneous tissues, and usually has an indolent clinical course. The second group has a gamma/delta phenotype, is cd8 negative, often co-expresses cd56, is not confined to the subcutaneous tissues, and usually has a poor prognosis. In the recent who-eortc classification, the term subcutaneous panniculitis-like t-cell lymphoma is reserved for cases with an alpha/beta, cd8 positive phenotype. Cases with a gamma/delta phenotype are included in the group of cutaneous gamma/delta t-cell lymphomas.
• subependymal giant cell astrocytoma - a benign, slowly growing tumor (who grade I) typically arising in the wall of the lateral ventricles and composed of large ganglioid astrocytes. It is the most common cns neoplasm in patients with tuberous sclerosis complex and typically occurs during the first two decades of life. (who)
• subependymoma - a benign, slow growing neoplasm which is typically attached to a ventricular wall. It is composed of glial tumor cell clusters embedded in an abundant fibrillary matrix with frequent microcystic change. Some lesions have the histological features of both subependymoma and ependymoma. It is often detected incidentally and has a very favorable prognosis. (adapted from who.)
• subglottic squamous cell carcinoma - a squamous cell carcinoma of the larynx that arises from the subglottic area. Symptoms include dyspnea and stridor. It spreads to the hypopharynx, trachea, and thyroid gland.
• sublingual gland adenocarcinoma - an adenocarcinoma that arises from the sublingual gland.
• sublingual gland carcinoma - a carcinoma that arises from the sublingual gland. Representative examples include cystadenocarcinoma and mucoepidermoid carcinoma.
• submandibular gland adenocarcinoma - an adenocarcinoma that arises from the submandibular gland. Representative examples include polymorphic low-grade adenocarcinoma and acinic cell carcinoma.
• submandibular gland adenoid cystic carcinoma - an aggressive carcinoma that arises from the submandibular gland. It is characterized by the presence of malignant epithelial and myoepithelial cells forming cribriform, tubular, and solid patterns. It usually presents as a slow growing mass. Patients develop pain because of the tendency of these carcinomas to invade perineural tissues.
• submandibular gland carcinoma - a carcinoma that arises from the submandibular gland. Representative examples include mucoepidermoid carcinoma, adenoid cystic carcinoma, and carcinoma ex pleomorphic adenoma.
• submandibular gland carcinoma ex pleomorphic adenoma - a carcinoma that arises from a pleomorphic adenoma in the submandibular gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.
• submandibular gland mucoepidermoid carcinoma - a carcinoma that arises from the submandibular gland. It usually presents as a firm and painless mass. It is characterized by the presence of epidermoid cells, mucus producing cells, and cells of intermediate type. The majority of cases have a favorable outcome.
• submandibular gland squamous cell carcinoma - an invasive squamous cell carcinoma that arises from the submandibular gland. It usually affects elderly patients and presents as a rapidly enlarging tumor mass, often associated with pain.
• submandibular gland undifferentiated carcinoma - a carcinoma that arises from the submandibular gland and is characterized by the presence of undifferentiated, anaplastic malignant epithelial cells.
• superficial fibromatosis - a poorly circumscribed, intermediate fibrocytic neoplasm arising from the superficial soft tissues. It is characterized by the presence of spindle-shaped fibroblasts, and an infiltrative growth pattern.
• supraglottic squamous cell carcinoma - a squamous cell carcinoma of the larynx that arises from the supraglottic area. Signs and symptoms include dysphagia, a sensation of foreign body in the throat, and hemoptysis. It spreads to the space anterior to the epiglottis, pyriform sinus, and base of the tongue.
• supratentorial embryonal tumor, not otherwise specified - a central nervous system embryonal tumor, not otherwise specified arising from the supratentorial region.
• sweat gland carcinoma - a carcinoma arising from the sweat glands. Representative examples include tubular carcinoma, spiradenocarcinoma, eccrine carcinoma, hidradenocarcinoma, and apocrine carcinoma.
• syringoma - a benign sweat gland neoplasm usually affecting the lower eyelids and upper cheeks. The lesions are papular and are usually numerous. Morphologically, there are nests, cords, and tubules of epithelial cells present, surrounded by a dense stroma in the reticular dermis.
• systemic mastocytosis - a variant of mastocytosis characterized by multifocal, dense infiltrates of mast cells (15 or more mast cells in aggregates) detected in the bone marrow and/or other extracutaneous sites. (who, 2001)
• systemic mastocytosis with an associated hematological neoplasm - a disorder characterized by systemic infiltration of internal organs by aggregates of neoplastic mast cells and the presence of a clonal non-mast cell hematologic neoplasm (e.G., myelodysplastic syndrome, chronic myeloproliferative disorder, acute myeloid leukemia, and lymphoma).
• t acute lymphoblastic leukemia - acute lymphoblastic leukemia of t-cell origin. It comprises about 15% of childhood cases and 25% of adult cases. It is more common in males than females. (who, 2001)
• t lymphoblastic leukemia/lymphoma - a neoplasm of lymphoblasts committed to the t-cell lineage, typically composed of small to medium-sized blast cells. When the neoplasm involves predominantly the bone marrow and the peripheral blood, it is called t acute lymphoblastic leukemia. When it involves nodal or extranodal sites it is called t lymphoblastic lymphoma. (who, 2001)
• t lymphoblastic lymphoma - the most frequent type of lymphoblastic lymphoma. It comprises approximately 85-90% of cases. It is more frequently seen in adolescent males. It frequently presents with a mass lesion in the mediastinum. Pleural effusions are common. (who, 2001)
• t-cell large granular lymphocyte leukemia - a t-cell peripheral neoplasm characterized by a persistent (>6 months) increase in the number of peripheral blood large granular lymphocytes, without a clearly identified cause. (who, 2001)
• t-cell large granular lymphocyte leukemia expressing the t-cell receptor gamma-delta - an uncommon variant of t-cell large granular lymphocyte leukemia expressing the gamma-delta t-cell receptor. Approximately 60% of these cases are cd8-positive and the remainder are cd4/cd8-negative.
• t-cell large granular lymphocyte leukemia, common variant - t-cell large granular lymphocyte leukemia defined by the presence of cd3-positive, cd8-positive, and t-cell receptor alpha-beta-positive cytotoxic t-cells.
• t-cell non-hodgkin lymphoma - a non-hodgkin lymphoma of t-cell lineage. It includes the t lymphoblastic lymphoma and the mature t- and nk-cell lymphomas. -- 2003
• t-cell proliferation of uncertain malignant potential - a t-cell lymphoproliferative disorder with uncertain malignant potential. A representative example is lymphomatoid papulosis.
• t-cell prolymphocytic leukemia - an aggressive t-cell leukemia, characterized by the proliferation of small to medium sized prolymphocytes with a mature t-cell phenotype, involving the blood, bone marrow, lymph nodes, liver, spleen, and skin. (who, 2001)
• t-cell prolymphocytic leukemia, cerebriform cell variant - a t-cell prolymphocytic leukemia characterized by the presence of neoplastic prolymphocytes with irregular or cerebriform nuclear outline.
• t-cell prolymphocytic leukemia, small cell variant - a t-cell prolymphocytic leukemia characterized by the presence of small neoplastic prolymphocytes often with invisible nucleolus by light microscopy.
• t-cell/histiocyte-rich large b-cell lymphoma - a large b-cell lymphoma characterized by the presence of a limited number of scattered neoplastic large b-lymphocytes which are admixed with numerous non-neoplastic t-lymphocytes and frequently histiocytes.
• tsh-producing pituitary gland carcinoma - a rare, hormonally functioning or non-functioning pituitary gland adenocarcinoma that produces thyrotropin.
• tanycytic ependymoma - a variant of ependymoma, often found in the spinal cord, with tumor cells arranged in fascicles of variable width and cell density. Ependymal rosettes are generally absent, so this lesion must be distinguished from astrocytic neoplasms, but its em characteristics are ependymal. (adapted from who.)
• tenosynovial giant cell tumor - a tumor usually arising in the synovium of joints, bursa or tendon sheath. It is characterized by the presence of mononuclear cells, multinucleated osteoclast-like giant cells, hemosiderin-laden macrophages, foam cells, and an inflammatory infiltrate. According to the growth pattern, it is classified as localized or diffuse.
• teratoma - a non-seminomatous germ cell tumor characterized by the presence of various tissues which correspond to the different germinal layers (endoderm, mesoderm, and ectoderm). It occurs in the testis, ovary, and extragonadal sites including central nervous system, mediastinum, lung, and stomach. According to the level of differentiation of the tissues which comprise the tumor, teratomas are classified as benign (grade 0 or 1), immature (grade 2), and malignant (grade 3). Grade 0 teratomas contain only mature elements; grade 1 teratomas have a limited degree of immaturity; grade 2 teratomas have a more extensive degree of immaturity; grade 3 teratomas are composed exclusively of immature tissues. The prognosis depends on patient age, tumor size and grade, and stage.
• testicular choriocarcinoma - a malignant germ cell tumor arising from the testis. It represents the rarest of the testicular germ cell tumors. Histologically it is characterized by the presence of syncytiotrophoblasts and cytotrophoblasts.
• testicular germ cell tumor - a germ cell tumor arising from the testis. Representative examples include teratoma, seminoma, embryonal carcinoma, and yolk sac tumor.
• testicular seminoma - a malignant germ cell tumor arising from the testis. It is believed that it is derived from the sexually undifferentiated embryonic gonad. Treatment with radiotherapy is highly successful when the tumor is diagnosed in localized stages, which represents the majority of presentations of seminoma.
• therapy-related leukemia - a leukemia arising as a result of the mutagenic effect of chemotherapy agents that are used for the treatment of a malignant tumor or exposure to ionizing radiation.
• therapy-related myelodysplastic syndrome - a myelodysplastic syndrome caused by chemotherapy and/or radiotherapy.
• therapy-related myelodysplastic/myeloproliferative neoplasm - a myelodysplastic/myeloproliferative neoplasm arising as a result of the mutagenic effect of chemotherapy agents and/or radiation that are used for the treatment of neoplastic or non-neoplastic disorders.
• thymic adenocarcinoma - a rare primary thymic carcinoma, characterized by the presence of carcinoma cells with glandular differentiation.
• thymic adenosquamous carcinoma - a rare carcinoma that arises from the thymus and is characterized by the presence of glandular and squamous carcinomatous components.
• thymic carcinoid tumor - a primary thymic neuroendocrine tumor, often associated with cushing syndrome. Two morphologic subtypes are recognized: typical and atypical carcinoid tumors. Atypical carcinoid tumors have a more aggressive clinical course.
• thymic carcinoma - a diverse group of carcinomas of the thymus gland, previously known as thymoma type c. It includes morphologic variants derived from purely epithelial cells, as well as from cells with neuroendocrine differentiation.
• thymic clear cell carcinoma - a rare, usually aggressive, primary thymic carcinoma, characterized by the presence of carcinoma cells with clear cytoplasm.
• thymic large cell neuroendocrine carcinoma - an aggressive, non-small cell, poorly differentiated thymic neuroendocrine carcinoma, characterized by the presence of a high mitotic rate and, almost always, necrosis.
• thymic lymphoepithelioma-like carcinoma - a rare, usually aggressive primary thymic carcinoma, characterized by a syncytial growth of undifferentiated carcinoma cells and the presence of a lymphoplasmacytic infiltrate. More than 40% of cases are associated with epstein-barr virus infection.
• thymic mucoepidermoid carcinoma - a rare primary thymic carcinoma, characterized by the presence of squamous cells, intermediate type cells, and mucus-producing cells. The prognosis depends on histologic grade and stage.
• thymic sarcomatoid carcinoma - a rare, usually aggressive, primary thymic carcinoma, characterized by the presence of tumor cells morphologically resembling soft tissue sarcoma.
• thymic small cell carcinoma - an aggressive, small cell, poorly differentiated thymic neuroendocrine carcinoma, characterized by the presence of a high mitotic rate and numerous apoptotic bodies.
• thymic squamous cell carcinoma - a rare primary thymic carcinoma, characterized by the presence of keratinizing or non-keratinizing malignant squamous cells. Approximately 10-20% of cases occur in combination with thymoma. The prognosis depends on the tumor stage and the degree of cellular differentiation.
• thymic undifferentiated carcinoma - a rare primary thymic carcinoma, characterized by an undifferentiated solid tumor growth, without associated sarcomatoid features.
• thymoma - a neoplasm arising from the epithelial cells of the thymus. Although thymomas are usually encapsulated tumors, they may invade the capsule and infiltrate the surrounding tissues or even metastasize to distant anatomic sites. The following morphologic subtypes are currently recognized: type a, type b, type ab, metaplastic, micronodular, microscopic, and sclerosing thymoma. Thymomas type b are further subdivided into types b1, b2, and b3. Thymoma type b3 usually has the most aggressive clinical course.
• thymoma type a - a thymic epithelial neoplasm characterized by the presence of spindle and/or oval neoplastic epithelial cells. Lymphocytic infiltration is minimal or absent. It may be associated with myasthenia gravis or pure red cell aplasia. The majority of cases occur in the anterior mediastinum as masaoka stage I tumors. Approximately 20% of the cases occur as stage ii or stage iii tumors. Type a thymoma generally behaves as a benign tumor and the overall survival is reported to be 100% at 5 and 10 years.
• thymoma type ab - a thymic epithelial neoplasm characterized by the presence of a lymphocyte-poor component similar to that seen in type a thymoma and a lymphocyte-rich component which contains neoplastic small polygonal epithelial cells. It may be associated with myasthenia gravis and pure red cell aplasia. The majority of cases occur in the anterior mediastinum as masaoka stage I tumors. A minority of the cases occur as stage ii or stage iii tumors. The overall survival is reported to be 80-100% at 5 and 10 years.
• thymoma type b - an epithelial neoplasm arising from the thymus. It may be associated with myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. It includes thymoma type b1 which is a thymoma of low grade malignant potential, thymoma type b2 which is a thymoma of moderate malignancy, and thymoma type b3 which is also known as well differentiated thymic carcinoma.
• thymoma type b1 - a thymic epithelial neoplasm characterized by the presence of expanded areas which resemble the normal thymic cortex. The neoplastic epithelial cells are small and scant and there is a dense t-lymphocytic component present. Areas of medullary differentiation with or without hassall's corpuscles are also present. It may be associated with myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. It has a low grade malignant potential. The majority of cases occur in the anterior mediastinum as masaoka stage I tumors. A minority of the cases occur as stage ii tumors.
• thymoma type b2 - a thymic epithelial neoplasm characterized by the presence of neoplastic large, polygonal epithelial cells with large vesicular nuclei and prominent nucleoli. The neoplastic cells are arranged around perivascular spaces and along septa. Immature t-lymphocytes are also present. It may be associated with myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. It is a tumor of moderate malignancy. The majority of cases occur in the anterior mediastinum as masaoka stage I, stage ii, or stage iii tumors. Metastatic, stage iv tumors occur less frequently.
• thymoma type b3 - also known as well-differentiated thymic carcinoma, atypical thymoma, or epithelial thymoma, this type of thymoma displays morphologic characteristics of a well-differentiated carcinoma. The majority of cases occur in the anterior mediastinum as masaoka stage ii or stage iii tumors. It is almost always invasive, it recurs frequently, and metastasizes in approximately 20% of the cases.
• thyroid gland adenocarcinoma - an adenocarcinoma arising from the follicular cells of the thyroid gland. According to the degree of differentiation, it is classified either as differentiated carcinoma (extensive evidence of follicular cell differentiation), or poorly differentiated carcinoma (limited evidence of follicular cell differentiation).
• thyroid gland anaplastic carcinoma - a primary carcinoma of the thyroid gland composed of undifferentiated cells. The malignant cells demonstrate evidence of epithelial differentiation, either by immunohistochemistry or electron microscopic studies. Microscopically, in the majority of cases there is a mixture of spindle, epithelioid, and giant cells. The vast majority of the patients present with a rapidly enlarging neck mass. The clinical course is usually aggressive.
• thyroid gland carcinoma - a carcinoma arising from the thyroid gland. It includes the following main subtypes: follicular, papillary, medullary, poorly differentiated, and undifferentiated (anaplastic) carcinoma.
• thyroid gland follicular adenoma - a benign, encapsulated tumor, arising from the follicular cells of the thyroid gland. It may be associated with thyroid hormone secretion but it does not have malignant characteristics.
• thyroid gland follicular carcinoma - a differentiated adenocarcinoma arising from the follicular cells of the thyroid gland. The nuclear features which characterize the thyroid gland papillary carcinoma are absent. Radiation exposure is a risk factor and it comprises approximately 10% to 15% of thyroid cancers. Clinically, it usually presents as a solitary mass in the thyroid gland. It is generally unifocal and thickly encapsulated and shows invasion of the capsule or the vessels. Diagnostic procedures include thyroid ultrasound and fine needle biopsy.
• thyroid gland medullary carcinoma - a neuroendocrine carcinoma arising from the c-cells of the thyroid gland. It is closely associated with multiple endocrine neoplasia syndromes. Approximately 10% to 20% of medullary thyroid carcinomas are familial. Patients usually present with a thyroid nodule that is painless and firm. In the majority of cases nodal involvement is present at diagnosis. Surgery is the preferred treatment for both primary lesions and recurrences. This carcinoma is generally not very sensitive to radiation and almost unresponsive to chemotherapy.
• thyroid gland mixed medullary and follicular cell carcinoma - a primary carcinoma of the thyroid gland containing a medullary carcinoma component that is immunohistochemically positive for calcitonin, and follicular cell carcinoma structures that are immunohistochemically positive for thyroglobulin.
• thyroid gland papillary carcinoma - a differentiated adenocarcinoma arising from the follicular cells of the thyroid gland. Radiation exposure is a risk factor and it is the most common malignant thyroid lesion, comprising 75% to 80% of all thyroid cancers in iodine sufficient countries. Diagnostic procedures include thyroid ultrasound and fine needle biopsy. Microscopically, the diagnosis is based on the distinct characteristics of the malignant cells, which include enlargement, oval shape, elongation, and overlapping of the nuclei. The nuclei also display clearing or have a ground glass appearance.
• thyroid gland squamous cell carcinoma - a rapidly growing primary carcinoma of the thyroid gland composed of malignant squamous cells. The clinical course is usually aggressive.
• thyrotroph adenoma - a rare adenoma of the anterior lobe of the pituitary gland that produces thyrotropin. It is usually associated with goiter and hyperthyroidism.
• tibial adamantinoma - an adamantinoma arising from the tibia. The tibia is the site which is more frequently involved by adamantinoma (80-90% of cases).
• tongue squamous cell carcinoma - a squamous cell carcinoma that arises from the tongue. It usually presents as a painful ulcerated or nodular lesion. The size of the tumor and the status of the lymph nodes are the most important factors that determine prognosis.
• topoisomerase ii inhibitor-related acute myeloid leukemia - acute myeloid leukemias arising as a result of the mutagenic effect of therapeutic agents targeting dna-topoisomerase ii. The vast majority of patients present without a preceding myelodysplastic phase. The acute myeloid leukemias are usually of the monoblastic or myelomonocytic type. Clonal cytogenetic abnormalities are frequently present and usually involve chromosome 11q23 (mll gene).
• tracheal adenoid cystic carcinoma - an adenoid cystic carcinoma that arises from the trachea. It spreads to the submucosal tracheal tissue and to regional lymph nodes.
• tracheal carcinoma - malignant epithelial neoplasm arising from the tracheal mucosa.
• tracheal squamous cell carcinoma - a rare squamous cell carcinoma that arises from the mucosal lining of the trachea. It usually grows as an intraluminal mass and later invades extraluminal structures. The majority of patients present with hemoptysis, coughing, dyspnea, or stridor.
• transitional cell carcinoma - a malignant neoplasm arising from the transitional epithelium, usually affecting the urinary bladder, ureter, or renal pelvis. It may or may not have a papillary configuration. It is graded 1 to 3 or 4 according to the degree of cellular differentiation and architectural patterns. Grade 1 transitional cell carcinoma is histologically benign but it may recur. Transitional cell carcinomas may also affect the upper respiratory tract and the ovaries.
• transitional meningioma - a who grade I meningioma characterized by the coexistence of meningothelial cells and fibrous architectural patterns.
• trichilemmal carcinoma - a rare malignant tumor arising from the outer hair sheath and infundibulum on the face. It is considered the malignant counterpart of tricholemmoma. Complete surgical excision is required.
• trichilemmoma - a benign neoplasm arising from the outer hair sheath and infundibulum. It occurs in the head and neck, usually on the face. It usually presents as an exophytic wart-like lesion or a dome-shaped lesion with smooth surface. Multiple facial lesions are usually associated with cowden disease.
• trichoblastoma - a benign hair follicle neoplasm with trichoblastic differentiation. It usually presents as a solitary papular lesion it most often presents on the head and neck area, but it may develop in any anatomic site containing hair follicles. Because of its benign nature, treatment usually is not required, provided that the diagnosis has been established with certainty.
• trilateral retinoblastoma - trilateral retinoblastoma refers to bilateral (or less often unilateral) retinoblastoma associated with an intracranial primitive neuroectodermal tumor in the pineal or suprasellar region. This syndrome is often associated with a increased familial incidence of retinoblastoma. (from cancer 86(1): 135-141, 1999).
• triple-negative breast carcinoma - an invasive breast carcinoma which is negative for expression of estrogen receptor (er), progesterone receptor (pr), and human epidermal growth factor receptor 2 (her2).
• trophoblastic tumor - a gestational or non-gestational neoplasm composed of neoplastic trophoblastic cells. Representative examples include hydatidiform mole and choriocarcinoma.
• type 1 papillary renal cell carcinoma - a papillary renal cell carcinoma characterized by the presence of papillae covered by small cells with scant amount of cytoplasm. The cells are arranged in a single layer on the basement membrane of the papillae.
• type 2 papillary renal cell carcinoma - a papillary renal cell carcinoma characterized by the presence of papillae covered by cells of a higher nuclear grade as compared to type 1 papillary renal cell carcinoma. The cells have eosinophilic cytoplasm and pseudostratified nuclei.
• type a lymphomatoid papulosis - a variant of lymphomatoid papulosis characterized by the presence of scattered anaplastic large lymphocytes, often resembling reed-sternberg cells, admixed with acute and chronic inflammatory cells.
• type b lymphomatoid papulosis - a variant of lymphomatoid papulosis characterized by an epidermotropic infiltrate composed of small atypical cerebriform-like lymphocytes.
• type c lymphomatoid papulosis - a variant of lymphomatoid papulosis characterized clinically by regressing skin papules, and morphologically by features resembling anaplastic large cell lymphoma.
• type I endometrial adenocarcinoma - a classification of primary endometrial adenocarcinomas that refers to endometrioid adenocarcinoma and mucinous adenocarcinoma.
• type I pleuropulmonary blastoma - a pleuropulmonary blastoma composed of malignant small cells. Sarcomatous features are absent.
• type ii endometrial adenocarcinoma - a classification of primary endometrial adenocarcinomas that refers to clear cell adenocarcinoma, serous adenocarcinoma, and serous endometrial intraepithelial carcinoma.
• type ii pleuropulmonary blastoma - a pleuropulmonary blastoma composed of malignant small cells and characterized by the presence of a sarcomatous component. It usually follows an aggressive clinical course.
• type iii pleuropulmonary blastoma - a pleuropulmonary blastoma characterized by a solid pattern and sarcomatous features. It usually follows an aggressive clinical course.
• typical acute promyelocytic leukemia - acute promyelocytic leukemia characterized by the presence of hypergranular promyelocytes and characteristic cells that contain bundles of auer rods.
• unclassified renal cell carcinoma - a renal cell carcinoma characterized by morphologic features that do not fit easily into one of the other well-defined categories of renal cell carcinoma. Examples of such features include mixtures of morphologic patterns, mucin production, and sarcomatoid morphology.
• undifferentiated carcinoma - a usually aggressive malignant epithelial neoplasm composed of atypical cells which do not display evidence of glandular, squamous, or transitional cell differentiation.
• undifferentiated pleomorphic sarcoma - an undifferentiated soft tissue sarcoma characterized by the presence of a pleomorphic malignant cellular infiltrate. It is also known as malignant fibrous histiocytoma.
• undifferentiated retinoblastoma - a retinoblastoma composed of small, undifferentiated cells. It is often associated with necrotic changes.
• undifferentiated stromal sarcoma - an infiltrating high grade mesenchymal tumor arising from the uterine corpus, cervix, vagina, and the ovary.
• unilateral breast carcinoma - breast carcinoma of one breast, or one side of the breast.
• unilateral retinoblastoma - a retinoblastoma that only involves a single eye.
• upper gingival squamous cell carcinoma - a squamous cell carcinoma of the oral cavity that arises from the upper gingiva.
• ureter carcinoma - a carcinoma of the ureter. The majority of ureter carcinomas are transitional cell and less frequently squamous cell carcinomas or adenocarcinomas.
• ureter squamous cell carcinoma - a rare squamous cell carcinoma that arises from the ureter.
• ureter urothelial carcinoma - a carcinoma that arises from the transitional epithelium of the ureter. It is associated with tobacco use and usually presents with gross or microscopic hematuria.
• urethral adenocarcinoma - an adenocarcinoma that arises from the male or female urethra.
• urethral carcinoma - a carcinoma that arises from the urethra. Morphologically, the tumors are similar to those described in the bladder.
• urethral squamous cell carcinoma - a well differentiated, moderately differentiated, or poorly differentiated squamous cell carcinoma that arises from the male or female urethra.
• urethral urothelial carcinoma - a transitional cell carcinoma that arises from the male or female urethra.
• uterine carcinosarcoma, heterologous type - a carcinosarcoma of the uterus characterized by the presence of sarcomatous elements composed of tissues that are not found in the uterus (e.G., bone, cartilage, skeletal muscle).
• uterine carcinosarcoma, homologous type - a carcinosarcoma of the uterus characterized by the presence of sarcomatous elements that arise from the tissues of the uterus.
• uterine corpus adenosarcoma - a primary polypoid malignant neoplasm of the uterine corpus characterized by the presence of a sarcomatous mesenchymal component and a benign epithelial component. Patients usually present with abnormal vaginal bleeding. It is considered a low grade malignant neoplasm and may recur following resection.
• uterine corpus carcinosarcoma - an aggressive malignant mixed epithelial and mesenchymal tumor that arises from the uterine corpus. It usually affects elderly postmenopausal women and presents with vaginal bleeding. It is characterized by the presence of a malignant epithelial component that is usually glandular and a sarcomatous component.
• uterine corpus endometrial stromal sarcoma - a uterine corpus sarcoma originating from the endometrial stroma. It is further subdivided into low grade and high grade endometrial stromal sarcoma.
• uterine corpus high grade endometrial stromal sarcoma - a rare, high grade sarcoma that arises from the endometrial stroma. It is characterized by round cell morphology. It was previously also known as undifferentiated uterine sarcoma. In 2014, high grade endometrial stromal sarcoma was reclassified and is currently considered a distinct and rare neoplasm. It appears to have a prognosis that falls between low grade endometrial stromal sarcoma and undifferentiated sarcoma.
• uterine corpus leiomyoma - a benign smooth muscle neoplasm arising from the body of the uterus. It is characterized by the presence of spindle cells with cigar-shaped nuclei, interlacing fascicles, and a whorled pattern.
• uterine corpus leiomyosarcoma - an aggressive malignant smooth muscle neoplasm, arising from the uterine corpus. It is characterized by a proliferation of neoplastic spindle cells.
• uterine corpus low grade endometrial stromal sarcoma - a rare, indolent, invasive mesenchymal tumor that arises from the endometrial stroma. It is characterized by the presence of a plexiform vasculature, infrequent mitoses, and insignificant cytologic atypia. Late recurrences may occur.
• vaginal adenocarcinoma - an adenocarcinoma arising from the vagina. Morphologic variants include the clear cell, endometrioid, mesonephric, and mucinous adenocarcinoma.
• vaginal adenosquamous carcinoma - a carcinoma that arises from the vagina and is characterized by the presence of malignant glandular and malignant squamous epithelial components.
• vaginal carcinoma - a carcinoma arising from the vaginal epithelium. The majority of vaginal carcinomas are squamous cell carcinomas.
• vaginal squamous cell carcinoma, not otherwise specified - a squamous cell carcinoma arising from the vagina. Human papillomavirus infection is associated with the development of vaginal intraepithelial neoplasia and invasive squamous cell carcinoma. Signs and symptoms include painless bleeding, postcoital bleeding, and urinary tract symptoms. Morphologically it resembles squamous cell carcinomas in other anatomic sites. Radiation therapy is the preferred treatment for most cases. The prognosis is related to the stage of the disease.
• verruca vulgaris - a wart caused by human papillomavirus.
• visual pathway astrocytoma - an astrocytoma that affects the visual pathway. This condition can be seen in association with neurofibromatosis 1. It is most commonly seen in the pediatric age group.
• visual pathway glioma - a glioma that arises from the visual pathway. This condition can be seen in association with neurofibromatosis 1. It is most commonly seen in the pediatric age group.
• vulvar adenocarcinoma - an adenocarcinoma that arises from the vulva. Representative examples include bartholin gland adenocarcinoma, eccrine adenocarcinoma, apocrine adenocarcinoma, and sebaceous carcinoma.
• vulvar basal cell carcinoma - a slow growing, locally infiltrating carcinoma that arises from the vulva. It is characterized by the presence of malignant cells that resemble the basal cells that are present in the epidermis.
• vulvar carcinoma - a carcinoma arising from the vulva. It usually affects elderly women but has been observed in premenopausal women as well. The most frequently seen histologic type is squamous cell carcinoma. The most common site of involvement is the labia majora. In many cases, the development of vulvar cancer is preceded by condyloma or squamous dysplasia.
• vulvar paget disease - an uncommon intraepithelial malignant neoplasm of eccrine or apocrine origin, arising from the vulva. It usually affects post-menopausal women. In approximately 10-20% of the cases there is an associated anorectal, or urothelial carcinoma or a skin appendage adenocarcinoma identified. It presents as a red, eczematous lesion. Microscopically, it is characterized by the presence of the typical paget cells which are large, round cells with abundant cytoplasm and prominent nuclei.
• vulvar squamous cell carcinoma - an invasive squamous cell carcinoma arising from the vulva. Risk factors include the human papilloma virus and cigarette smoking. Precursor lesions include the vulvar intraepithelial neoplasia, lichen sclerosus with associated squamous cell hyperplasia, and chronic granulomatous vulvar disease such as granuloma inguinale. Symptoms include vulvar pruritus or irritation, discharge, bleeding, and pain. The following morphologic variants have been identified: keratinizing, non-keratinizing, basaloid, warty, verrucous, keratoacanthoma-like, and squamous cell carcinoma with tumor giant cells. Risk factors for recurrence include advanced stage, tumor diameter greater than 2.5 cm, multifocality, capillary-like space involvement, associated vulvar intraepithelial neoplasia grades 2 or 3, and margins of resection involved by tumor. (who, 2003)
• waldenstrom macroglobulinemia - lymphoplasmacytic lymphoma associated with bone marrow involvement and igm monoclonal gammopathy.
• warthin tumor - an adenoma characterized by an oncocytic, often papillary, epithelial component, dense lymphoid stroma, and cystic spaces. It occurs primarily in the parotid gland, and is the second most common benign parotid salivary gland tumor. A strong association with smoking has been reported. It typically presents as a painless swelling in the lower portion of the parotid gland.
• well differentiated adrenal cortex carcinoma - an adrenal cortex carcinoma characterized by the presence of morphologic and cytologic features reminiscent of the normal adrenal cortex and absence of sarcomatous or anaplastic features.
• well differentiated leiomyosarcoma - grade I malignant smooth muscle neoplasm. It is characterized by a proliferation of neoplastic spindle cells.
• well differentiated liposarcoma - a locally aggressive malignant neoplasm composed of mature adipocytes showing cell size variation and nuclear atypia. It is often associated with the presence of hyperchromatic multinucleated stromal cells, and varying numbers of lipoblasts. There are three histologic subtypes, sclerosing, inflammatory, and spindle cell liposarcoma. These tumors do not usually metastasize unless they undergo dedifferentiation.
• well differentiated papillary mesothelioma - a localized or multifocal mesothelioma arising from the peritoneum and less often the pleura. Cases arising from the peritoneum predominantly occur in women. It is characterized by the formation of papillae, covered by a single layer of blunt mesothelial cells. Mitotic figures are not present. There is no evidence of severe cytologic atypia. It has a relatively favorable clinical outcome, compared to malignant mesothelioma.
• well differentiated prostate adenocarcinoma - an invasive prostate adenocarcinoma characterized by the presence of well differentiated malignant glandular epithelial components.
• wilms tumor - an embryonal neoplasm characterized by the presence of epithelial, mesenchymal, and blastema components. The vast majority of cases arise from the kidney. A small number of cases with morphologic features resembling wilms tumor of the kidney have been reported arising from the ovary and the cervix.
• yolk sac tumor - a non-seminomatous malignant germ cell tumor composed of primitive germ cells. It is the most common malignant germ cell tumor in the pediatric population. It occurs in the infant testis, ovary, sacrococcygeal region, vagina, uterus, prostate, abdomen, liver, retroperitoneum, thorax, and pineal/third ventricle. The tumor mimics the yolk sac of the embryo and produces alpha-fetoprotein (afp). Treatment includes: surgical resection, radiation, and chemotherapy. This tumor is very responsive to chemotherapy regimens that include cisplatinum.