A rare case of apocrine carcinoma of the breast: Cytopathological and immunohistopathological study.

Invasive apocrine carcinomas of the breast are rare. Fine needle aspiration cytology (FNAC) has been increasingly used as a primary screening tool for breast lumps, with high level of sensitivity and specificity. Preoperatively, apocrine carcinoma needs to be distinguished from benign apocrine lesions and other eosinophilic and granular cell tumors. We report a rare case of invasive apocrine carcinoma in a 70-year-old female presenting with a breast lump and no axillary lymphadenopathy. FNAC was advised which yielded moderately cellular smears composed of loosely cohesive clusters of large, polygonal cells with centrally located pleomorphic, vesicular nucleus with prominent nucleoli and abundant, basophilic and granular cytoplasm. Based on above cytomorphological findings, diagnosis of apocrine carcinoma was offered. The patient then underwent right modified radical mastectomy with axillary clearance. Based on histomorphology and panel of immunohistochemical (IHC) markers the diagnosis was confirmed. Although apocrine/oncocytic cytomorphology is seen in few types of breast neoplasms, high index of suspicion and subsequent IHC study clinches the diagnosis.