Overview of Moles (Nevi)
Moles, or nevi (singular: nevus), are the most common growths in humans. They can be present at birth or acquired throughout life. The incidence of nevi increases throughout childhood, peaks in adolescence, and typically wanes in older adulthood. Nevi evolve and change throughout childhood and during pregnancy.
Moles can appear anywhere on the skin in various sizes and shapes. They are made up of melanocytes, skin cells that produce melanin (dark pigment).
Moles typically evolve and grow as we do. They generally begin as flat brown spots, similar to a freckle, that, over time, may grow larger, become elevated, and grow hairs.
Certain types of moles carry a risk for developing malignant melanoma, a serious form of skin cancer. Sunburns, particularly in childhood, can increase the risk.
Some moles are present at birth. Congenital nevi are seen on over 1% of newborns. They can be small, or they can cover most of the skin surface. Large nevi are at highest risk for malignant changes.
One relatively common mole is the dysplastic nevus. It is broader and larger than an ordinary mole and tends to be irregular in color and shape. People with dysplastic moles have a greater than average chance of developing melanoma.
While most changes in moles are not cancerous, it is important to consult a dermatologist with concerns about moles, especially if unusual changes in them can be observed. The dermatologist may recommend that a biopsy be taken. This involves removal of part or all of the mole for evaluation.