Unusual Cutaneous Malignancies

Malignant tumors of the skin represent a large and complex spectrum. Basal and squamous cell carcinoma, malignant melanoma, and cutaneous lymphoma, are common skin cancers with well-described clinical presentation, diagnostic considerations, and management. On the other hand, uncommon types of cutaneous cancers are mainly cited in the literature as case reports and their etiology, pathogenesis, prognosis, and treatment are speculative because of their rarity. This chapter deals with rare types of cutaneous malignancies, providing a background of epidemiological and clinical features, pathological diagnosis, and management for each of these malignancies. This discussion outlines tumors that are grouped according to the cell of origin. This includes rare tumors of the epidermis and epidermal appendages, cutaneous malignant soft tissue tumors (including fibrous and fibrohistiocytic tumors, vascular and perivascular tumors, and muscle and fat tumors), and neuroectodermal tumors.