Fine Needle Aspiration Cytologic Features of Medullary Carcinoma of the Breast : A Study of 20 Cases with Histologic Correlation

To analyze fine needle aspiration cytology (FNAC) material from 20 cases of histologically verified medullary carcinoma (MC) of the breast and correlate the cytomorphologic features with histologic appearance to improve the diagnostic sensitivity and specificity of FNAC. We reviewed the cytologic features of 20 cases of MC of the breast in the archives of Ege University Hospital between 1994 and 2006. Twenty patients with an aspirate and confirmed diagnosis of MC were identified. Patient age was 30-74 years (mean, 48). The initial cytologic diagnoses were positive for cancer in 17 cases, atypical/suspicious for cancer in 2 cases and negative for cancer in 1 case. The cytologic picture was characterized by cellular smears composed of highly atypical epithelial tumor cells in loosely cohesive sheets and lying singly, admixed with polymorphous lymphocytes, plasma cells and neutrophils. Tumor cells had predominantly abundant finely granular, eosinophilic cytoplasm and moderate to marked nuclear pleomorphism with prominent nudcleoli. Histologic examination confirmed that 11 cases were atypical MC and 9 were pure MC. Breast MC is a rare, distinct category that appears to have rather characteristic cellular features. Familiarity with the cell components is a prerequisite in cytologic accuracy.