Abstract: Objective: To explore the clinically efficacy of multiple modified Mohs microsurgery (mMMS) in treating extramammary Paget's disease (EMPD). Methods: A retrospective review was carried out to analyze the clinical data of 8 cases of primary EMPD (pEMPD) treated by MMS during Aug. 2021 to Dec. 2022 in our hospital. Results: All eight patients underwent preoperative photodynamic therapy to judge the tumor margins. Among these patients, two patients underwent traditional wide local excision (WLE) therapy, three patients underwent the rapid peripheral MMS (rpMMS), and the other three patients underwent the slow peripheral MMS (spMMS). One patient treated with WLE had a false negative margin, and was treated with radiotherapy. No false negative margin was found in the other patients treated with WLE or rpMMS. Conclusions: Adopting the peripheral MMS (pMMS) to treat pEMDP can ensure the complete resection rate and improve surgical efficiency at the same time. spMMS can effectively avoid the inaccuracy of EMPD frozen sections and the risks of infection and bleeding caused by large-area wound exposure.

Key words: extramammary Paget's disease, Mohs microsurgery