Neuroendocrine Carcinoma of the Skin.

Neuroendocrine carcinoma (NEC) is often referred to as Merkel cell carcinoma of the skin, trabecular cell carcinoma, cutaneous apudoma, and primary small-cell carcinoma of the skin. NEC is derived from Merkel cells found in the hair follicles of mammals that form complexes with terminal axons to act as mechanoreceptors to pressure. Merkel cells are also found in the dermis, epidermis, and oral cavity. NEC is usually found in sun-exposed areas, with 50% in the head and neck. NEC appears most often in the white population and at an average age of 65 years. A poorer prognosis is associated with men, with younger age, with location in the head, neck, and trunk areas, and with regional or systemic disease. The disease is rare but aggressive. The one-, two-, and three-year survival rates are 88%, 72%, and 55%, respectively.2