Concordance Between a Mohs Surgeon and a Dermatopathologist in Evaluating Mohs Cryosections.

BACKGROUND: Mohs micrographic surgery is the gold standard treatment for high-risk non-melanoma skin cancers. The success of Mohs relies on accurate histopathologic evaluation. Due to law restrictions in some European countries Mohs surgeons are not permitted to report on histopathology, therefore a pathologist evaluates the frozen sections.

OBJECTIVE: To retrospectively assess the concordance between the certified Mohs surgeon and the pathologist in evaluating the Mohs slides that were intraoperatively evaluated by the pathologist.

MATERIALS AND METHODS: Frozen section slides of a total of 237 Mohs cases between 2013-2020 were examined by the blinded Mohs surgeon and the tumors were marked on copy maps. The copy maps and the original maps were compared and the non-concordant cases were reevaluated together by the Mohs surgeon and the dermatopathologist. The concordance rate was calculated and the inter-rater agreement was statistically analyzed using Cohen's Kappa coefficient.

RESULTS: We report high concordance rate (97.9%) and inter-rater agreement (0.96) of Mohs surgeon and dermatopathologist in evaluating Mohs slides.

CONCLUSION: As a newly settled center, our results are in alignment with experienced centers where the Mohs surgeon evaluates the slides herself and performs the surgery.