Fine needle aspiration cytodiagnosis of secretory carcinoma of the breast.

Secretory carcinoma (SC) of the breast is a rare variant of breast malignancy and its cytological features in fine needle aspirates have only recently been described. In this communication, our experience with four cases of SC of the breast is presented in which the diagnosis was established on fine needle aspiration cytology (FNAC). In all cases, the samples were cellular and featured diffuse, prominent, intracytoplasmic vacuoles and secretion in malignant cells and occasional signet-ring like forms. The cytodiagnosis of SC in all the cases correlated with subsequent examination of cell blocks of the aspirate and tissue. Cytochemical stains showed diffuse positivity for mucin by alcian blue stain in the vacuolated cells which was periodic acid-Schiff positive and resistant to diastase digestion. Oil-red O staining was negative. Immunopositivity to carcinoembryonic antigen, cytokeratin (CAM 5.2), B72.3 and epithelial membrane antigen was found in malignant cells. The cytodiagnostic criteria for SC of the breast, characteristic cytological features which are useful in a correct FNAC diagnosis and differentiation from other pertinent breast carcinomas, are discussed.