Recurrence of moderately dysplastic nevi with positive histologic margins.

Background: The Pigmented Lesion Subcommittee of the Melanoma Prevention Working Group recently published a consensus statement that incompletely excised moderately dysplastic nevi (MDN) without clinical residual pigmentation can be observed and not re-excised. However, data regarding recurrence of MDN with positive histologic margins are quite scant.

Objective: We sought to extend the reported findings with a study to determine the recurrence rate of MDN with positive histologic margins.

Methods: We performed a retrospective study on MDN with positive histologic margins that were not re-excised and for which at least 1 year of clinical follow-up was available.

Results: We found a total of 147 such nevi from January 1, 2007, to December 31, 2013. Six MDN (5 compound and 1 junctional) or 4% recurred with an average recurrence time of 1.7 years. All of these MDN were evaluated by shave biopsies.

Limitations: Subjectivity in grading of atypia is a limitation of this study.

Conclusion: These data from a large study focusing exclusively on recurrence of MDN with positive histologic margins support the conclusion of the Pigmented Lesion Subcommittee that incompletely excised MDN do not require re-excision.