Margin Status in Shave Biopsies of Nonmelanoma Skin Cancers: Is It Worth Reporting?

Abstract

Context.—The practice of reporting margin status in biopsies is relatively unique to biopsies of the skin and highly variable among pathologists. Objective.—To address the accuracy of margin evaluation in shave biopsies of nonmelanoma skin cancers. Design.—We collected shave biopsies of squamous and basal cell carcinomas that appeared to have uninvolved margins on routine sign out. We obtained deeper levels on corresponding tissue blocks until blocks were exhausted and examined them for tumor at biopsy margins. Results.—Forty-seven consecutive cases were collected, including 20 squamous cell (43%) and 27 basal cell (57%) carcinomas. Eleven of 47 cases (23%) with negative margins at initial diagnosis demonstrated positive margins upon deeper-level examination. Margins of 8 of 27 basal cell carcinomas (30%) and 3 of 20 squamous cell carcinomas (15%) were erroneously classified as “negative” on routine examination. Conclusions.—No guidelines exist regarding the reporting of margins in nonmelanoma skin cancer biopsies, and reporting practices vary extensively among pathologists. We found that nearly one-quarter of positive margins in shave biopsies for cutaneous carcinomas are missed on standard histologic examination. Moreover, reporting of a positive margin may also be misleading if the clinician has definitively treated the skin cancer at the time of biopsy. For these reasons, and as routine exhaustion of all tissue blocks is impractical, the decision to include or exclude a comment regarding the margin status should be given conscious consideration, accounting for the clinical intent of the biopsy and any known information regarding postbiopsy treatment.