Risk of cutaneous malignant melanoma in patients with nonfamilial atypical nevi from a pigmented lesions clinic.

Abstract

Atypical nevi (AN) are regarded as a major risk factor for occurrence of malignant melanoma. Few studies report an increase in relative risk for melanoma in patients with nonfamilial AN. We measured the risk of melanoma in 195 patients with nonfamilial AN. In a retrospective follow-up study the number of newly diagnosed melanomas during follow-up were inventoried. Included patients were invited for skin screening and nevus count. On the basis of our calculations, the relative risk for invasive melanoma in patients with nonfamilial AN, including those patients with a history of melanoma, is 41. For individuals with AN without a previously diagnosed melanoma, the relative risk was 37. Multivariate analysis did not reveal a specific risk factor for the occurrence of melanoma (including number of AN) because of small numbers. Invasive melanomas occurred in persons having 1, 5, 12, and 172 AN, respectively. An increased risk for invasive cutaneous malignant melanoma in patients with nonfamilial AN was established.