Cutaneous Type Adnexal Tumors Outside the Skin

Cutaneous adnexal neoplasms are complex lesions, including benign and malignant neoplasms in addition to malformations and hamartomas. They show one or several features of differentiation along follicular, sebaceous, apocrine, and eccrine lines. Rarely, cutaneous adnexal neoplasms or their mimics may arise outside the skin. In some organs, such as the parotid gland, a number of tumors comprise well-established entities, whereas in the majority of cases an extracutaneous occurrence of cutaneous-type adnexal lesions is a rare and often diagnostically challenging finding. This review discusses various authentic cutaneous-type adnexal neoplasms or related lesions presented according to the organ involved.