melanoma (MEH-luh-NOH-muh)

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

Anatomy of the skin with melanocytes; drawing shows normal skin anatomy, including the epidermis, dermis, hair follicles, sweat glands, hair shafts, veins, arteries, fatty tissue, nerves, lymph vessels, oil glands, and subcutaneous tissue. The pullout shows a close-up of the squamous cell and basal cell layers of the epidermis above the dermis with blood vessels. Melanin is shown in the cells. A melanocyte is shown in the layer of basal cells at the deepest part of the epidermis.