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. 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.