Apocrine Carcinoma of the Axilla with Predominant Signet Ring Cell Features - A Case Report

Apocrine carcinoma arising from the apocrine sweat glands is a rare cutaneous malignant tumor which occurs predominantly in the axilla of elderly individuals. The typical histologic features of apocrine carcinoma is within a well developed glandular lumina with abundant eosinophilic cytoplasm and evidence of decapitation secretion. In rare instances, predominant signet ring cell features in apocrine carcinoma has been reported. We experienced a case that occured in the right axilla of a 59-year-old. Histopathologic examination showed a solid tumor that extended from the upper dermis into the subcutis, with a delicate infiltrate of epithelial cells. The cells had granular amphophilic cytoplasm, predominantly showed distinct signet ring cell morphology, and were strongly positive for epithelial mucin. Both lysozyme and gross cystic disease fluid protein-15 were identified in the tumor cells. We diagnosed this to be a case of primary signet ring cell apocrine carcinoma of the axilla after several immunohistochemical and clinical evaluations.