Mixed apocrine-medullary carcinoma of the breast. Report of a case with fine needle aspiration cytology.

The case of an unusual variant of breast carcinoma arising in an 80-year-old woman is presented. Fine needle aspiration (FNA) cytology of this carcinoma revealed sheets of cells showing apocrine differentiation and significant cellular atypia mixed with lymphocytes and plasma cells. At mastectomy, the neoplasm was found to have features of both apocrine carcinoma and medullary carcinoma, with a prominent lymphocytic infiltrate. This case underlines the difficulty in distinguishing between malignant apocrine cells and apocrine metaplastic cells by FNA cytology. The presence of an inflammatory component, as seen in this case, may compound such difficulties.