What Is Melanoma

Melanoma is a form of skin cancer that arises from melanocytes - the cells that produce pigment. Melanoma may begin in association with a mole. Melanocytes produce a pigment called melanin that gives the skin its colour and protects it from sun damage. Darker skin has more melanin and more protection. Melanocytes often cluster together and form moles (nevi). Most moles are benign, but some may go on to become malignant melanomas.

Images:

Click on any of the Melanoma images below to enlarge. Click here for More Melanoma Images.

Melanomas are divided into 4 main types, depending on their location, shape and whether they grow outward or downward into the dermis:

Superficial Spreading Melanoma

This often begins as a flat dark stain on the skin or appears as a change to a pre-existing mole. It accounts for 2/3 of all melanomas.

Nodular Melanoma

This is usually unrelated to a pre-existing mole. A smooth nodule appears, and it is often blue-black in colour – it may grow rapidly and spread to the lymph glands quickly.

Acral Lentiginous Melanomas

This occurs on the palms of the hand, on the soles of the feet or under nail beds, and can grow and spread quickly. In dark-skinned people it accounts for most of melanomas.

Lentigo Maligna Melanoma

This is quite common on chronically sun-exposed skin and usually appears on the face of elderly people.

Video:

Please view a short video (82 seconds) on what Melanoma looks like. The video is available in three formats:

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In situ melanoma

The earliest form of melanoma, it is small and does not extend beneath the surface of the skin

Stage I melanoma

Tumours are less than 2mm in thickness, found in the outer layer of the skin (epidermis) and/or the upper part of the inner layer of the skin (dermis)

Stage II melanoma

The carcinoma spreads to the lower part of the inner layer of the skin (dermis) but not into the tissue below. It can spread into fat tissue as well.

Stage III melanoma

The carcinoma spreads to nearby lymph nodes.

Stage IV melanoma

The carcinoma spreads beyond the skin to distant sites or organs

Melanoma can also start in the mucous membranes of the mouth, anus and vagina, in the eye or other places in the body where melanocytes are found. See Other Skin Cancers for more information.

(Some material, facts, and figures have been adapted from The BC Cancer Agency (www.bccancer.bc.ca) and The Canadian Cancer Society (www.cancer.ca).

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