Carcinomas of sweat glands - Report of 60 cases

Context.-Several aspects of sweat gland carcinomas (incidence, classificati on, diagnosis, and behavior) have not been definitively clarified and need to be studied further. Objective.-The clinicopathologic findings of a large series of sweat gland carcinomas, collected during a period of 15 years, are presented. Methods.-Sixty sweat gland carcinomas (41 porocarcinomas, 3 syringomatous c arcinomas, 8 ductal carcinomas, 5 adenoid cystic carcinomas, and 3 mucinous carcinomas) were analyzed histologically and immunohistochemically. Results.-Porocarcinomas were composed of eosinophilic and clear atypical ce lls arranged in solid-cystic lobular masses. These tumors were divided into 2 subgroups: horizontal porocarcinomas, showing a prominent intraepidermal component, and nodular porocarcinomas, which demonstrated predominant nodu lar growth. Syringomatous carcinomas presented keratinizing and nonkeratini zing cysts, dilated tubules (sometimes with a "tadpole" appearance), small neoplastic ducts, solid islands, and cellular cords. Ductal carcinomas were characterized by a prominent formation of tubules, solid islands, and cell ular cords. Adenoid cystic carcinomas presented a characteristic pattern, s howing basaloid monomorphous cells with moderately atypical nuclei, arrange d in cribriform or solid islands and in tubular structures. Mucinous carcin omas were composed of moderately atypical cells with eosinophilic vacuolate d cytoplasm, forming solid and cystic islands floating in large mucin pools . Immunohistochemically, cytokeratin was found in neoplastic cells in all c ases, carcinoembryonic antigen was detected in 73% of cases, and actin-posi tive (myoepithelial) cells were not found. Conclusions.-Although numerous studies have been published in recent years, the histologic features, histogenesis, and classification of sweat gland c arcinomas still remain controversial and need to be clarified by further st udies.