About the Disease

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer.

Sometimes referred to as a neuroendocrine carcinoma of the skin, MCC arises from uncontrolled growth of Merkel cells in the skin that share some common characteristics with normal Merkel cells in the skin. MCC primarily occurs on highly sun-exposed skin such as the head/neck and arms, but it can occur anywhere on the body, including sun-protected areas. MCC usually develops as a painless, firm bump that can be red-purple or skin-colored. Patients frequently point out a new MCC to their doctor because a bump is growing rapidly and/or does not look like anything the patient has ever had before.

Learn more about Merkel cells, MCC, its symptoms and appearances, and when a bump may be serious enough to see a specialist.