Rare emerging malignant skin tumors

: As clinical skills improve and innovative diagnostic techniques become available in the field of dermatology and dermatopathology, new types or additional variants of malignant skin tumors are described. This article reviews the current nomenclature, clinico-pathological features, differential diagnosis, prognostic and therapeutic implications of some new dermato(patho)logical rare emerging skin tumors, including epithelial tumors (squamous cell carcinoma with mucinous metaplasia), adnexal tumors (endocrine mucin-producing sweat gland carcinoma), soft tissue tumors of vascular differentiation (pseudolymphomatous cutaneous angiosarcoma, pseudomyogenic hemangioendothelioma), hematopoietic tumors (blastic plasmacytoid dendritic cell neoplasm) and mixed epithelial/melanocytic tumor (squamomelanocytic tumor).