Merkel Cell Carcinoma
Merkel Cell Carcinoma (MCC), also known as neuroendocrine carcinoma of the skin, is a very aggressive cancer. It is rare, with around 1400 new cases per year in the US. MCC is a cancer of older adults with a history of significant sun exposure. It has recently been linked to a virus (Merkel cell polyomavirus) that most adults have been exposed to during their lifetimes. It is thought that an interaction of the viral DNA and ultraviolet light from the sun can lead to formation of this cancer later in life. Patients with Merkel cell carcinoma are not contagious. Due to the rarity of MCC, no large studies have been performed, and no clear treatment guidelines have been developed for this malignancy. MCC can appear as a pink bump on the skin that grows quickly to form a red, bleeding mass. Treatment includes excision of the skin tumor by Mohs micrographic surgery or wide excision. Radiation therapy is often added, although a definite benefit has not been proved. Prognosis depends on the stage of the disease at the time of diagnosis. Small tumors (<2 cm) removed surgically before metastasis can be cured in up to 90% of patients. If the MCC has already metastasized, the prognosis is very poor.