People with dysplastic nevi and a family history of dysplastic nevi and melanoma tend to develop the cancer at an earlier age than melanoma patients who don’t have such nevi. Individuals who have dysplastic nevi but no family history of dysplastic nevi and melanoma may also develop melanoma at a relatively early age, but less often.
At times it is difficult to distinguish between dysplastic nevi and early melanomas. (Sometimes, melanomas will begin within a dysplastic nevus.) To establish the difference, a doctor will remove the entire spot or a portion of it for examination in the pathology laboratory. Some physicians recommend examining the mole with a dermoscope, which magnifies and allows visualization of internal structures and colors not seen by the naked eye.
Melanoma in a dysplastic nevus-asymmetry, border irregularity, color variegation, 1/3 inch.
Melanoma arising in a solitary dysplastic nevus-black, brown, and pink color variegation, size 1/2 inch.
Normal MolesThe average young adult has about 10 to 20 such spots or growths. Generally, normal moles (melanocytic nevi) have the following characteristics:
SHAPE: symmetrical, round or oval
BORDER: regular, sharp and well-defined
COLOR: uniform, usually tan, brown, or skin color
DIAMETER: usually 6 mm (1/4 inch) or smaller
LOCATION: often concentrated on sun-exposed areas of the face, trunk, arms and legs
ONSET: most often during early childhood through ages 35-40
UNIFORMITY: normal moles resemble one another
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.
Dysplastic nevus on lower back.
Close-up demonstrates asymmetry, color variegation and border irregularity.
Dysplastic nevus on right upper back.
Close-up shows ill-defined borders, asymmetry and color variegation
GROWTH: Enlargement of a previously stable mole or appearance of a new mole after ages 35-40 should raise suspicion.
SURFACE: Central portion often is raised, whereas the peripheral portion is usually flat, sometimes with tiny "pebbly" elevations.
APPEARANCE: greatly varied; dysplastic nevi often look different from one another.
NUMBER: From a few to well over 100 dysplastic nevi may be present.
Having numerous moles, whether atypical or normal, is a risk factor for melanoma. Don't wait for more serious warning signs of melanoma to appear, such as:
- BLUISH-BLACK COLOR
REMEMBER, ANY MOLE (PIGMENTED SPOT OR GROWTH) THAT UNDERGOES A SIGNIFICANT CHANGE IN SIZE, SHAPE, OR COLOR — OR THAT CAUSES SYMPTOMS OF ITCHING OR BLEEDING — SHOULD BE SUSPECTED OF BEING A MELANOMA.