Merkel cell carcinomas.

Merkel cell carcinoma (MCC) is a rare and extremely aggressive skin cancer that arises from primary neural cells. It presents most commonly in the elderly and immunocompromised patients. Pathologically, MCC should be distinguished from extrapulmonary small cell lung cancer or metastatic small cell lung cancer or a small cell variant of melanoma. The prognosis is based largely on the stage of disease at the time of presentation. Therapeutic options for MCC include wide resection with or without adjuvant radiotherapy or chemotherapy. Novel therapies based on the understanding of the molecular aspects of MCC are currently being explored.