What Is Merkel Cell Carcinoma (MCC)?

Merkel cell carcinoma (MCC) is a rare type of skin cancer. Merkel cells are thought to be a type of skin neuroendocrine cell, because they share some features with nerve cells and hormone-making cells. Merkel cells are very close to nerve endings in the skin. They help us sense light touch, which lets us do things like feel the fine details on an object’s surface.

Merkel cell carcinoma (MCC)

Merkel cell skin cancer (carcinoma) starts when the Merkel cells in the skin start to grow out of control. It tends to grow quickly and can spread to other parts of the body.

Merkel cell carcinoma is also sometimes called neuroendocrine carcinoma of the skin. Another name for MCC is trabecular carcinoma (or trabecular cancer).

MCC is much less common than most other types of skin cancer, but it’s one of the most dangerous types. It’s much more likely than common skin cancers (squamous and basal cell skin cancers) to spread to other parts of the body, and it can be hard to treat if it has spread.

Merkel cell carcinomas can start anywhere on the skin, but most often they start on skin that's exposed to the sun, like the face (the most common site), neck, and arms. A very small portion start in other parts of the body, such as inside the nose or esophagus.

Merkel cell tumors often look like firm, pink, red, or purple lumps or bumps on the skin. They usually don't hurt, but they tend to grow quickly and can sometimes open up as ulcers or sores (see Signs and Symptoms of Merkel Cell Carcinoma).

Other types of skin cancer

There are other, more common skin cancers. For more on these types of cancers, see Basal and Squamous Cell Skin Cancer and Melanoma Skin Cancer.

Less common types of skin cancer

Other, much less common types of skin cancer include:

• Kaposi sarcoma
• Lymphoma of the skin
• Skin adnexal tumors (tumors that start in the hair follicles or glands on the skin, such as sweat glands)
• Various types of sarcomas