Congenital pigmented moles (nevi)

Small congenital pigmented moles (brown birth marks) are present in one percent of all newborn babies, although most people develop their moles later in childhood or adulthood. Giant congenital moles (larger than 8 inches) are rare, and found in fewer than one in 20,000 newborn infants. Babies with giant congenital moles clearly have an increased risk of developing melanomas.

What to expect

The risk of change to melanoma, a dangerous cancer, of small and medium-sized congenital moles is slightly increased, but the exact amount of that increased risk is controversial. There are many studies being performed currently to try to determine more precisely how much of a risk there is.

It is important to inspect congenital moles on a regular basis at home. We often recommend that a dermatologist examine the patient yearly, with serial photographs being considered for some moles. Signs of early change to melanoma include the development of irregular borders, changes in color and a change in the smooth surface of the mole. Any of these changes should prompt a call to your dermatologist with evaluation shortly thereafter. A congenital mole may develop hair growth or uniformly darken (and these are expected changes which are usually not of concern).

Treatment

Since there is a small risk of these congenital moles becoming melanoma, we may recommend removal for some of them. Most often removal can be performed when the child is older with local anesthesia. Yearly check ups by a dermatologist are also strongly suggested, as are regular skin self examinations by older children (and parental examination for younger children). Strict sun protection with sunscreens and sun avoidance are also strongly encouraged.

Related glossary terms