Melanoma is a malignant tumour of melanocytes. Melanocytes predominantly occur in the skin but can be found elsewhere, especially the eye. The vast majority of melanomas originate in the skin.
Epidemiologic studies suggest that exposure to ultraviolet radiation is one of the major contributors to the development of melanoma. Other candidates are mutations in or total loss of tumor suppressor genes.
Important factors in determining risk include the intensity and duration of solar exposure, the age at which solar exposure occurs, and the degree of skin pigmentation (see skin types).
Exposure during childhood is a more important risk factor than exposure in adulthood. (This is seen in migration studies in Australia where people tend to retain the risk profile of their country of birth if they migrate to Australia as an adult). Fair and red-headed people are at greater risk.
Some other risk factors include the "dysplastic naevus syndrome", a previous history of melanoma, and a history of melanoma in the immediate family.
Diagnosis of melanoma requires expert knowledge, as early stages may look identical to harmless moles or not have any color at all. Beyond this expert knowledge a biopsy is often required to assist in making the diagnosis, confirming the diagnosis and in defining the severity of the melanoma.
A popular method for remembering the signs and symptoms of melanoma is the mnemonic ABCDE:
Asymmetrical skin lesion
Border of the lesion is irregular
Color: melanomas are often black but can be multicolored; any change in color should prompt a doctor's visit.
Diameter: any mole that increases in diameter or any large mole should be seen by a dermatologist.
Evolution: any changes in the above categories should be watched closely by a dermatologist.
Sometimes the skin lesion may bleed, itch, or ulcerate. A slow-healing lesion should be watched closely, as that may be a sign of melanoma.
Common Cancer Types
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