Biopsy Margins for Dysplastic Nevi May Not Be Indicative of True Margin Status

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Clinicians should be aware that biopsy margins for dysplastic nevi may not be indicative of true margin status when contemplating re-excision.

Biopsy margins do not represent true margin status and should be used with caution when performing re-excision in the management of dysplastic nevi, a study in the Journal of the American Academy of Dermatology suggests.

A retrospective review of the University of Alabama Birmingham’s Department of Dermatology pathology database was performed. The review consisted of identifying biopsy reports between 2015 and 2017 that used the words “dysplastic” and “nevus.” The negative predictive value of biopsy margins was calculated by comparing biopsy specimen margin assessments with excision pathology reports. The researchers also evaluated the frequency of residual nevus on excision following positive biopsy margins.

The review yielded a total of 1245 dysplastic nevi tumors from 934 patients (male 45.7% and female 54.3%; mean age, 50 years). Overall, the pooled negative predictive value was 87.3% for moderate, moderate to severe, and severely dysplastic nevi. No association was found between age (P =.62), sex (P =.84), race (P =.7), biopsy type (P =.7), diameter (P =.27), nevus type (P =.07), or location (P =.23) between tumors with and without residual nevus present on excision in dysplastic nevi tumors with moderate or greater atypia with negative initial biopsy margins. The researchers identified residual nevus on excision in 29.41% of dysplastic nevi cases comprising moderate atypia or greater with initially positive biopsy margins.

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Limitations of the study include its retrospective nature, which did not note whether the intent of each biopsy was to remove the entire lesion or sample it, as well as the inclusion of data from only one center.

“Our study provides additional evidence that reported biopsy margins are not representative of true margin status,” the researchers wrote. They recommend that “dermatologists use this information to make more informed decisions about treatment recommendations.”

Disclosure: The study authors declared no affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

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Duncan JR, Purnell JC, Stratton MS, Pavlidakey PG, Huang C, Phillips CB. Negative predictive value of biopsy margins of dysplastic nevi: a single institution retrospective review [published online July 18, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.07.037