Myoblastomatoid carcinoma of the breast: An unusual variant of apocrine carcinoma: Report of a case with fine-needle aspiration cytology and immunohistochemical study

Fine-needle aspiration cytology, immunohistochemistry, and histopathologic findings are described in a case of myoblastomatoid carcinoma of the breast. The aspirate contained many small and large clusters of cohesive atypical cells with abundant foamy-to-granular cytoplasm and nuclei that show moderate pleomorphism. These tumors can be easily misinterpreted as either fibrohistiocytic or myoblastomatoid (granular cell) tumors, and by using immunohistochemical stains, the epithelial origin can be elucidated. This case report provides the first description of the fine-needle aspiration cytomorphology of this distinctive variant of apocrine carcinoma.