Home > Encyclopedia of Cancer > Merkel Cell Carcinoma

Definition

Merkel cell carcinoma (MCC) is a rare form of cancer that develops on, or just beneath, the skin and in hair follicles.

Description

Merkel cells are cells that lie in the middle layers of the skin. These cells are organized around hair follicles and are believed to act as some type of touch receptors. MCC begins in these cells.

MCC usually appears as firm shiny skin lumps, or tumors. These tumors are painless and can range in size from less than a quarter of an inch (0.6 cm) to over two inches (5.1 cm) in diameter. They may be red, pink, or blue. Tumors generally first appear on the head and neck and less frequently on other sun-exposed parts of the body.

MCC is very aggressive,...