Medullary breast carcinoma

It is histologically characterized as poorly differentiated cells with abundant cytoplasm and pleomorphic high grade vesicular nuclei.

[citation needed] Very rare cases of it have been diagnosed in men (see male breast cancer).

There must be histologic evidence of lymphoplasmacytic infiltration, noninvasive microscopic circumscription, greater than 75% syncytial growth pattern, and high-grade nuclei.

The American Joint Committee on Cancer (AJCC) revised the staging system in 2018 to include the anatomic extent of the disease as well as prognostic biomarkers.

Immunological and histological testing should also be obtained for receptor status, which influences the type of treatment required.

The best measure of prognosis is through staging and axillary lymph node involvement in the absence of metastatic disease.

On histopathology, medullary breast carcinoma is characterized by groups of tumor cells with syncytial appearance (that is, seemingly fused cytoplasms, at left). There is typically also a lymphocytic and plasma cell infiltrate (right). [ 5 ]