Definition of Melanoma:

Melanoma is the most dangerous type of skin cancer. It is the leading cause of death from skin disease.

It involves cells called melanocytes, which produce a skin pigment called melanin. Melanin is responsible for skin and hair color.

Melanoma can also involve the colored part of the eye. For information about that form of melanoma, see melanoma of the eye.

See also:

• Basal cell skin cancer
• Skin cancer
• Squamous cell skin cancer

Causes, incidence, and risk factors:

There are 4 major types of melanoma:

• Superficial spreading melanoma is the most common type of melanoma. It is usually flat and irregular in shape and color, with varying shades of black and brown. It may occur at any age or body site, and is most common in Caucasians.
• Nodular melanoma usually starts as a raised area that is dark blackish-blue or bluish-red, although some are without color.
• Lentigo maligna melanoma usually occurs in the elderly. It is most common in sun-damaged skin on the face, neck, and arms. The abnormal skin areas are usually large, flat, and tan with intermixed areas of brown.
• Acral lentiginous melanoma is the least common form of melanoma. It usually occurs on the palms, soles, or under the nails and is more common in African Americans.

Melanoma can spread very rapidly. Although it is less common than other types of skin cancer, the rate of melanoma is steadily increasing. It is the leading cause of death from skin disease.

In the United States, 1 in 65 people will be diagnosed with melanoma at some point in their life. The risk of developing melanoma increases with age, but the disease also frequently affects young, otherwise healthy people. Melanoma is the number one cause of cancer death in women aged 25 - 30.

Melanoma may appear on normal skin, or it may begin at a mole or other area that has changed in appearance. Some moles present at birth may develop into melanomas.

The development of melanoma is related to sun exposure, particularly to sunburns during childhood, and is most common among people with fair skin, blue or green eyes, and red or blond hair.

Risk factors include the following:

• Family history of melanoma
• Red or blond hair and fair skin
• Presence of multiple birthmarks
• Development of precancerous lesions
• Obvious freckling on the upper back
• Three or more blistering sunburns before age 20
• Three or more years spent at an outdoor summer job as a teenager
• High levels of exposure to strong sunlight