[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Views 1,100
Citations 0
Original Investigation
December 2016

Reexamining the Threshold for Reexcision of Histologically Transected Dysplastic Nevi

Author Affiliations
  • 1Dermatology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
  • 2Pigmented Lesion and Melanoma Program, Department of Dermatology, Stanford University Medical Center and Cancer Institute, Stanford, California
  • 3Pathology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
  • 4Dermatopathology Section, Department of Pathology, Stanford University Medical Center, Stanford, California
JAMA Dermatol. 2016;152(12):1327-1334. doi:10.1001/jamadermatol.2016.2869
Key Points

Question  What proportion of incompletely excised, mildly to moderately dysplastic nevi progress to melanoma with long-term patient follow-up?

Findings  In this cohort study of 590 dysplastic nevi, favorable patient outcomes were observed over 20 years in most dysplastic nevi with positive histologic margins that were not further excised. Only 1 case of melanoma in situ arose 5 years later from an excisionally biopsied moderately dysplastic nevus with positive histologic margins, and 5 other melanomas developed at partial biopsy sites that likely represented sampling error.

Meaning  Mildly to moderately dysplastic nevi biopsied with excisional intent but with histologically involved margins can generally be clinically monitored without reexcision.


Importance  Controversy persists regarding the appropriate management of incompletely excised, biopsy-proven, mild and moderate dysplastic nevi (DN).

Objective  To determine long-term risk of associated melanoma in biopsied mild or moderate DN with positive histologic margins that were clinically observed vs reexcised with negative margins.

Design, Setting, and Participants  Retrospective cohort study of mixed referral and community patients from an academic pigmented lesion clinic and dermatology clinics of the affiliated Veteran Affairs medical center with biopsy-confirmed DN with positive histologic margins diagnosed from May 15, 1991, to July 8, 2015, and followed up through May 30, 2016. A consecutive sample of 1473 histologically confirmed DN was identified using surgical pathology databases at the study sites; 590 cases in 498 patients met eligibility criteria.

Main Outcomes and Measures  The primary outcome was the proportion of biopsied DN that progressed to histologically confirmed invasive or in situ melanoma. Secondary outcomes included local nevus recurrence and development of primary melanoma at other anatomic sites.

Results  The 498 patients had a mean (range) age of 57.6 (14-93) years and 90% were male. Among 590 positive-margin DN, 191 were reexcised and 399 clinically observed without further surgery; 170 reexcised and 304 observed DN had available follow-up data, with mean (SD) follow-up of 5.5 (4.6) years. Cases in the observation group were more likely to demonstrate nevus recurrence than those that were reexcised (3.3% vs 0%; P = .02). Six of 304 (2.0%) observed DN subsequently developed melanoma at the same site, compared with 1 of 170 (0.6%) that were reexcised (P = .43). Five of 6 observed patients who developed melanoma initially underwent partial biopsy with grossly positive margins; 1 melanoma in situ evolved from an excisionally biopsied moderately dysplastic nevus 5 years later. Only 1 case of thin invasive melanoma (≤1 mm) was observed, and no deaths from melanoma arising from biopsy-proven DN occurred through the latest dermatology follow-up. New primary melanoma developed at other sites in 9.9% of excised and 9.4% of resected DN.

Conclusions and Relevance  In cases of mild and moderate DN with microscopically positive margins and no concerning clinical residual lesion, observation, rather than reexcision, was a reasonable management option. Partial biopsies of pigmented lesions suspicious for melanoma may lead to delayed melanoma diagnosis and should be discouraged.