B-cell lymphoma

The B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph nodes. They develop more frequently in older adults and in immunocompromised individuals.

B-cell lymphomas include both Hodgkin's lymphomas and most non-Hodgkin lymphomas. They are typically divided into low and high grade, typically corresponding to indolent (slow-growing) lymphomas and aggressive lymphomas, respectively. As a generalisation, indolent lymphomas respond to treatment and are kept under control (in remission) with long-term survival of many years, but are not cured. Aggressive lymphomas usually require intensive treatments, with some having a good prospect for a permanent cure.

Prognosis and treatment depends on the specific type of lymphoma as well as the stage and grade. Treatment includes radiation and chemotherapy. Early-stage indolent B-cell lymphomas can often be treated with radiation alone, with long-term non-recurrence. Early-stage aggressive disease is treated with chemotherapy and often radiation, with a 70-90% cure rate. Late-stage indolent lymphomas are sometimes left untreated and monitored until they progress. Late-stage aggressive disease is treated with chemotherapy, with cure rates of over 70%.

Types

Micrograph showing Hodgkin's lymphoma, a type of B cell lymphoma that is usually considered separate from other B cell lymphomas. Field stain.

CT scan of primary B cell lymphoma in the left ilium, as diffuse cortical and trabecular thickening of the hemipelvis, mimicking Paget's disease.

There are numerous kinds of lymphomas involving B cells. The most commonly used classification system is the WHO classification, a convergence of more than one, older classification systems.

Common

Five account for nearly three out of four patients with non-Hodgkin lymphoma:

• Diffuse large B-cell lymphoma (DLBCL)
• Follicular lymphoma
• Marginal zone B-cell lymphoma (MZL) or Mucosa-Associated Lymphatic Tissue lymphoma (MALT)
• Small lymphocytic lymphoma (also known as chronic lymphocytic leukemia, CLL
• Mantle cell lymphoma (MCL)

Rare

The remaining forms are much less common:

• DLBCL variants or sub-types of
  • Primary mediastinal (thymic) large B cell lymphoma
  • T cell/histiocyte-rich large B-cell lymphoma
  • Primary cutaneous diffuse large B-cell lymphoma, leg type (Primary cutaneous DLBCL, leg type)
  • EBV positive diffuse large B-cell lymphoma of the elderly
  • Diffuse large B-cell lymphoma associated with chronic inflammation
  • Fibrin-associated diffuse large B-cell lymphoma
  • Primary testicular diffuse large B-cell lymphoma
• Burkitt's lymphoma
• Lymphoplasmacytic lymphoma, which may manifest as Waldenström's macroglobulinemia
• Nodal marginal zone B cell lymphoma (NMZL)
• Splenic marginal zone lymphoma (SMZL)
• Intravascular lymphomas variants
  • Intravascular large B-cell lymphoma
  • Intravascular NK-cell lymphoma
  • Intravascular T-cell lymphoma
• Primary effusion lymphoma
• Lymphomatoid granulomatosis
• Primary central nervous system lymphoma
• ALK+ large B-cell lymphoma
• Plasmablastic lymphoma
• Large B-cell lymphoma arising in HHV8-associated multicentric Castleman's disease
• B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma
• B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma

Other

Additionally, some researchers separate out lymphomas that appear to result from other immune system disorders, such as AIDS-related lymphoma.

Classic Hodgkin's lymphoma and nodular lymphocyte predominant Hodgkin's lymphoma are now considered forms of B-cell lymphoma.

Associated chromosomal translocations

Chromosomal translocations involving the immunoglobulin heavy locus (IGH@) is a classic cytogenetic abnormality for many B-cell lymphomas, including follicular lymphoma, mantle cell lymphoma and Burkitt's lymphoma. In these cases, the immunoglobulin heavy locus forms a fusion protein with another protein that has pro-proliferative or anti-apoptotic abilities. The enhancer element of the immunoglobulin heavy locus, which normally functions to make B cells produce massive production of antibodies, now induces massive transcription of the fusion protein, resulting in excessive pro-proliferative or anti-apoptotic effects on the B cells containing the fusion protein.

In Burkitt's lymphoma and mantle cell lymphoma, the other protein in the fusion is c-myc (on chromosome 8) and cyclin D1 (on chromosome 11), respectively, which gives the fusion protein pro-proliferative ability. In follicular lymphoma, the fused protein is Bcl-2 (on chromosome 18), which gives the fusion protein anti-apoptotic abilities.

See also

• Richter's transformation
• T-cell lymphoma

External links

• Overview and video at harvard.edu
• Lymphoma Association – Specialist UK charity providing free information and support to patients, their families, friends and carers

B-cell lymphoma Resources
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