Apocrine adenocarcinoma of the bilateral axillae

A case of apocrine adenocarcinoma arising in the bilateral axillae is reported. The patient was an 88-year-old Japanese male who complained of a mass lesion and pus-like discharge in the right axilla. Another mass was also noticed in the left axilla. No other neoplastic lesion was found in other sites of the body. The histologic appearances of the bilateral axillary tumors were almost identical. Both were adenocarcinoma with varying degrees of differentiation, composed of glands and nests of atypical epithelial cells with abundant eosinophilic cytoplasm. Some neoplastic cells exhibited cytoplasmic projections on their apical surface. Foci of in situ carcinoma were observed within the neoplastic tissue in the bilateral axillae. The neoplastic cells were immunohistochemically positive for epithelial membrane antigen (EMA) and gross cystic disease fluid protein (GCDFP-15), but negative for carcinoembryonic antigen (CEA). On the basis of their histologic and immunohistochemical features and distinctive location, the tumors were diagnosed as apocrine adenocarcinoma.