Merkel cell carcinoma (MCC) usually starts on areas of skin exposed to the sun, especially the face, neck, arms, and legs, but it can occur anywhere on the body. It often first appears as a single pink, red, or purple shiny bump that usually doesn't hurt. Sometimes the skin on the top of the tumor breaks open and bleeds.
These tumors grow quickly. They might spread as new lumps in the nearby skin. They might also reach nearby lymph nodes (small collections of immune system cells throughout the body). Over time, the lymph nodes might grow large enough to be seen or felt as lumps under the skin (usually in the neck or under the arm).
Merkel cell carcinoma is rare, and it can look like many other, more common types of skin cancer or other skin problems when it first appears. Because of this, doctors usually don't suspect MCC at first, and the diagnosis is often made only after the tumor is biopsied.
It’s very important to have any new, growing, or changing lumps, bumps, or spots on your skin checked by a doctor as soon as possible so that the cause can be found and treated, if needed. The earlier any type of skin cancer is found, the easier it might be to treat.
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Last Revised: October 9, 2018
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