Mohs micrographic surgery and dermatopathology concordance; An analysis of 1421 Mohs cases over 17 years.

BACKGROUND: The success of Mohs micrographic surgery depends on the surgeon's ability to correctly interpret intraoperative frozen sections.

OBJECTIVE: This retrospective study analyzed the rate of concordance between Mohs surgeons and dermatopathologists in reading slides from Mohs surgery cases.

METHODS: A dermatopathologist reviewed all the frozen sections and the corresponding Mohs map for every 30th Mohs case at a practice employing 6 different Mohs surgeons from 2001-2017. Cases in which the dermatopathologist and the Mohs surgeon disagreed on the interpretation were noted.

RESULTS: The concordance rate between Mohs surgeons and dermatopathologists was 99.79%. The three discordant cases included one case each of squamous cell carcinoma, superficial basal cell carcinoma, and hypertrophic squamous cell carcinoma in situ.

LIMITATIONS: This analysis is limited to fellowship-trained Mohs surgeons and therefore may not be applicable to all physicians who perform Mohs.

CONCLUSIONS: Fellowship-trained Mohs surgeons show very high concordance with board-certified dermatopathologists in the accurate and precise interpretation of histology slides in the setting of Mohs micrographic surgery.