Carcinomas of Sweat Glands

Abstract Context.—Several aspects of sweat gland carcinomas (incidence, classification, 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 carcinomas, 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 cells 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 nodular growth. Syringomatous carcinomas presented keratinizing and nonkeratinizing cysts, dilated tubules (sometimes with a “tadpole” appearance), small neoplastic ducts, solid isla...