[Eccrine sweat gland carcinoma of the skin]

Sweat gland carcinomas represent a group of morphological heterogeneous tumors with clear differences regarding clinical course and prognosis. The most relevant and accepted entities are described clinically and histopathologically with special reference to the differentiation from benign adnexal tumors. Carcinomas arising from preexisting benign adnexal tumors such as spiradenocarcinoma, cylindrocarcinoma, malignant mixed tumors of the skin are easily recognized. To establish the diagnosis of microcystic adnexal carcinoma or aggressive digital papillary adenocarcinoma can be more difficult, because these carcinomas do not show cytological criteria for malignancy and may therefore resemble benign adnexal tumors especially in small specimens.