Mammary secretory carcinoma

A rare type of breast cancer

Mammary secretory carcinoma is a rare type of breast cancer characterized by its unique histological appearance and clinical behavior. It was first described in children and young adults but can occur in individuals of any age. This carcinoma is notable for its indolent nature and generally favorable prognosis compared to other forms of breast cancer.

Histopathology

Histopathology of secretory carcinoma, high magnification

Mammary secretory carcinoma is distinguished by its histological features, which include the presence of abundant secretory material within the tumor cells. Under the microscope, the tumor exhibits a microcystic, tubular, and solid growth pattern. The cells are typically polygonal with abundant eosinophilic cytoplasm and vesicular nuclei. A hallmark of this carcinoma is the presence of intracellular and extracellular secretory material that stains positively with periodic acid-Schiff (PAS) stain.

Genetic Characteristics

A defining genetic feature of mammary secretory carcinoma is the presence of the ETV6-NTRK3 gene fusion. This chromosomal translocation t(12;15)(p13;q25) results in the fusion of the ETV6 gene on chromosome 12 with the NTRK3 gene on chromosome 15. This genetic alteration is also found in other types of secretory carcinomas, such as those occurring in the salivary glands.

Clinical Presentation

Patients with mammary secretory carcinoma typically present with a palpable breast mass. The tumor is often well-circumscribed and may be mistaken for a benign lesion on initial examination. Although it can occur at any age, it is more commonly diagnosed in younger individuals, including children and adolescents.

Diagnosis

The diagnosis of mammary secretory carcinoma is confirmed through a combination of histopathological examination and molecular testing for the ETV6-NTRK3 fusion. Immunohistochemical staining may also be used to support the diagnosis, with the tumor cells typically expressing markers such as S-100 protein and mammaglobin.

Treatment

The primary treatment for mammary secretory carcinoma is surgical excision, which may involve a lumpectomy or mastectomy depending on the size and location of the tumor. Sentinel lymph node biopsy is often performed to assess for regional lymph node involvement. Adjuvant therapies, such as radiation or chemotherapy, may be considered based on individual patient factors and the extent of disease.

Prognosis

The prognosis for patients with mammary secretory carcinoma is generally favorable, with a high rate of long-term survival. The tumor is typically slow-growing and less likely to metastasize compared to other types of breast cancer. However, local recurrence can occur, emphasizing the importance of adequate surgical margins during initial treatment.

Related pages

• Breast cancer
• Histopathology
• Gene fusion