Role of Observation for Excisionally Biopsied Moderately Dysplastic Nevi with Positive Histologic Margins and Risk of Future Melanoma Development

In a retrospective study of 438 patients with excisionally biopsied moderately dysplastic nevi with positive margins, conducted over 23 years, it was found that none of the 467 cases developed melanoma at the biopsy site during an average follow-up of 6.9 years. However, 22.8% of patients developed melanoma at a different site. A history of melanoma or dysplastic nevi prior to the diagnosis was significantly associated with an increased risk of future melanoma, with odds ratios of 7.79 and 2.1, respectively. The central dermatopathology review agreed with initial diagnoses 85% of the time, with a small percentage of cases being upgraded in atypia level and one case reclassified as melanoma in situ, which did not recur after 5 years. The study supports the management approach of observation for such nevi, while recognizing an increased risk of melanoma development at other sites for patients with a history of multiple dysplastic nevi.