Nonmelanoma skin cancer.

Nonmelanoma skin cancer (NMSC) is the most common form of malignancy in humans. The incidence of NMSC continues to increase despite increased awareness and sun-protective measures. If neglected or mismanaged, NMSC can cause significant morbidity and even death. The most common forms of NMSC on the head and neck include basal cell carcinoma, squamous cell carcinoma, sebaceous carcinoma, eccrine porocarcinoma, Merkel cell carcinoma, atypical fibroxanthoma, and microcystic adnexal carcinoma. Surgery is the mainstay of treatment (standard excision, Mohs micrographic surgery, curettage); however, other modalities exist, including radiation, topical immunomodulators, photodynamic therapy, and new systemic medications.