Low rates of clinical recurrence after biopsy of benign to moderately dysplastic melanocytic nevi

Background: Little is known about the recurrence/persistence rates of dysplastic nevi (DN) after biopsy, and whether incompletely removed DN should be re-excised to prevent recurrence.

Objective: Our purpose was to determine the recurrence rates of previously biopsied DN, and to assess whether biopsy method, margin involvement, congenital features, epidermal location, and degree of dysplasia are associated with recurrence.

Methods: Patients having a history of a "nevus biopsy" at least 2 years earlier were assessed for clinical recurrence. Slides of original lesions were re-reviewed by a dermatopathologist.

Results: A total of 271 nevus biopsy sites were assessed in 115 patients. Of 195 DN with greater than 2 years of follow-up, 7 (3.6%) demonstrated recurrence on clinical examination. In all, 98 DN had a follow-up period of at least 4 years with no clinical recurrence. Of 61 benign nevus biopsy sites examined, clinical recurrence was observed in two (3.3%). For all nevi, recurrence was significantly associated with shave biopsy technique but not with nevus dysplasia or subtype, or the presence of positive margin or congenital features.

Limitations: Most biopsies were performed in a pigmented lesion clinic at a single tertiary referral center. Determinations of nevus recurrence were made on clinical rather than histologic grounds, and follow-up times were limited in some cases.

Conclusion: In this cohort, rates of clinical recurrence after biopsy of DN and benign nevi were extremely low. Re-excision of nevi, including mildly to moderately DN with a positive margin, may not be necessary.