Abstract
A tumor on the scrotal skin of a 77-year-old patient was studied light and electron-microscopically. Tumor cells with a marked atypicality proliferated from a part of normal sweat duct toward the epidermis and formed numerous luminal structures. Histochemically, succinic dehydrogenase positive tumor cells were present within the epidermis and sweat ducts, and did not penetrate the basal membrane. Narrow lumina lined by tumor cells with microvilli were seen electron microscopically. Thus, the tumor was diagnosed as eccrine dermal ductocarcinoma in situ.
