QMy patient has a biopsy-proven moderately dysplastic nevus with positive histologic margins – does this need an excision or can this site just be closely observed?

A
Rachel Printy, PA-C

Rachel Printy, PA-C

PA-C

Medically reviewed on 06.01.2024 by Nick Brownstone, MD

The answer is, it depends. Is there visible pigment there still? Does your patient have a history of melanoma?

If the answer is no to both of these questions, I personally monitor these patients and will only do an excision or a deeper/wider re-shave if the lesion repigments.

A multicenter (9 US academic dermatology sites) retrospective cohort study was conducted of patients 18 years or older with moderately dysplastic nevi with positive histologic margins and 3 years or more of follow-up data collected consecutively from January 1, 1990, to August 31, 2014. Records were reviewed for patient demographics, biopsy type, pathologic findings, and development of subsequent cutaneous melanoma at the biopsy site or elsewhere on the body. 

A total of 467 moderately dysplastic nevi with positive histologic margins from 438 patients were evaluated. No cases developed into cutaneous melanoma at biopsy sites, with a mean follow-up time of 6.9 years. However, 100 patients (22.8%) developed a cutaneous melanoma at a separate site.

This study suggests that close observation with routine skin surveillance is a reasonable management approach for moderately dysplastic nevi with positive histologic margins. However, having 2 or more biopsied dysplastic nevi (with 1 that is a moderately dysplastic nevus) appears to be associated with increased risk for subsequent cutaneous melanoma at a separate site, so these patients need to be seen frequently.

If I suspect my patient has dysplastic nevi syndrome, I will have them see me for a total body skin exam every 6 months. And if my patient has a personal history of melanoma, I will usually go ahead and excise these biopsy-proven moderate DNs regardless of residual visible pigmentation being present or not.

References:

  1. Kim C, Chen S. Risk of Subsequent Cutaneous Melanoma in Moderately Dysplastic Nevi Excisionally Biopsied but With Positive Histologic Margins. JAMA Dermatol. 2018 Dec; 154(12): 1401–1408. Published online 2018 Oct 10. doi: 10.1001/jamadermatol.2018.3359