Melanoma is the most dangerous type of skin cancer. It involves the cells that produce the skin pigment melanin. Melanin is responsible for skin and hair color. Melanoma can also involve the colored part of the eye. (See also skin cancer and melanoma of the eye.)

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 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 and is the most deadly form of skin cancer. 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 85 people will develop melanoma at some point in their life. The risk of developing melanoma increases with age, but nonetheless the disease 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

The primary symptom of any skin cancer is usually a mole, sore, lump, or growth on the skin. Any change in appearance of a pigmented skin lesion over time is a warning sign. Also, watch for any bleeding from a skin growth.

The ABCD system may help you remember features that might be a symptom of melanoma:

• Asymmetry: One half of the abnormal area is different from the other half
• Borders: The lesion or growth has irregular edges.
• C olor: Color changes from one area to another, with shades of tan, brown, or black (sometimes white, red, or blue). A mixture of colors may appear within one lesion.
• Diameter: The trouble spot is usually (but not always) larger than 6 mm in diameter -- about the size of a pencil eraser.

The key to treating melanoma is recognizing symptoms early. You might not notice a small spot of concern if you don't look carefully, so perform thorough self-examinations on a regular basis.

If you notice any suspicious skin markings, see your health care provider as soon as possible.

The American Cancer Society recommends professional skin examinations every year for people older than 40, and every 3 years for people aged 20 - 40. Monthly self-examination is also recommended.

Your health care provider may suspect melanoma based on the appearance of the growth, sore, or lump. A biopsy may be used to confirm the diagnosis. The biopsy may involve removal of a small area of a growth, or the entire growth itself.