Endocrine mucin-producing sweat gland carcinoma occurring on extra-facial site: a case report.

Cutaneous endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a very rare low-grade malignant neoplasm analogous to the mammary solid-papillary carcinoma. It frequently expresses neuroendocrine markers and may show mucinous differentiation. Although the nodules are circumscribed, myoepithelial cells cannot be showed in most cases and about half of the cases are associated with invasive mucinous carcinoma. Hence, it has been suggested to be invasive and the precursor lesion of some primary cutaneous mucinous carcinomas. After being recognized as a distinct entity, all cases reported to date occurred either in the periocular region or on the cheek. Two thirds of the patients were female. Herein we present an unusual case of in situ EMPSGC on the chest wall skin of a middle-aged man.