DYSPLASTIC NEVI (atypical moles) are unusual benign moles that may resemble melanoma. People who have them are at increased risk of developing single or multiple melanomas. The higher the number of these moles someone has, the higher the risk; those who have 10 or more have 12 times the risk of developing melanoma compared to the general population. Dysplastic nevi are found significantly more often in melanoma patients than in the general population.
Medical reports indicate that about 2 to 8 percent of the Caucasian population have these moles. Heredity appears to play a part in their formation. Those who have dysplastic nevi plus a family history of melanoma (two or more close blood relatives with the disease) have an extremely high risk of developing melanoma. Individuals who have dysplastic nevi, but no family history of melanoma, still face a 7 to 27 times higher risk of developing melanoma compared to the general population—certainly a great enough risk to warrant monthly self-examination, regular professional skin exams and daily sun protection.
These generally large, "atypical" moles are one of the most important risk factors for melanoma. Clinically, these moles can look like melanomas. They usually have the following characteristics:
SHAPE: often asymmetrical: A line drawn through the middle would not create matching halves.
BORDER: irregular and/or hazy-the mole gradually fades into the surrounding skin.
COLOR: variation and irregularity with subtle, haphazard areas of tan, brown, dark brown, red, blue or black.
DIAMETER: generally larger than 6 mm (1/4 inch), the size of a pencil eraser, but may be smaller.
LOCATION: most commonly on the back, chest, abdomen and extremities; may also occur on normally unexposed areas such as the buttocks, groin or female breasts, as well as on the scalp.