Dysplastic Nevi

The term "atypical nevus" or "atypical mole" has supplanted "dysplastic nevus." The diagnosis of atypical moles is made clinically and not histologically, and moles should be removed only if they are suspected to be melanomas. Clinically, these moles are large (> 5 mm in diameter), with an ill-defined, irregular border and irregularly distributed pigmentation. It is estimated that in Dysplastic Nevi 5–10% of the United States population have one or more atypical nevi.

Studies of Dysplastic Nevi have defined an increased risk of melanoma in the following populations: patients with 50 or more nevi with one or more atypical moles and one mole at least 8 mm or larger, and patients with a few to many definitely atypical moles. These patients of Dysplastic Nevi deserve education and regular (usually every 6–12 months) follow-up. Kindreds with familial melanoma (numerous atypical nevi and a strong family history) deserve even closer attention, as the risk of developing single or even multiple melanomas in these individuals approaches 50% by age 50.