Dermoscopy-guided Mohs micrographic surgery in post-laser basal cell carcinomas: is dermoscopy helpful for demarcation of the surgical margin?

Abstract

Background Mohs micrographic surgery (MMS) in cases where the tumor margin is poorly defined to the naked eye can lead to the need to take an increased number of Mohs stages. Objective To evaluate the usefulness of dermoscopy in determining MMS surgical margins of BCCs with a history of ablative laser treatment. Methods Patients were randomly allocated to naked eye (n = 69) or dermoscopy (n = 64) groups by the surgical margin detection method. Surgical outcomes of 133 post-laser BCC patients treated with MMS were analyzed. Results The lateral margin involvement rate at the first MMS stage was significantly lower in the dermoscopy group than in the naked eye group (4.7% vs. 29.0%; p < .001). However, the deep margin involvement rate at the first and mean MMS stages were not significantly different between the groups. The ablative laser treatment duration correlated to the number of MMS stages (p = .026). Conclusion The results demonstrated that lateral margin was mostly controlled within the first MMS stage with dermoscopy. Dermatosurgeons could focus on the deep margin after the first MMS stage; thus, the performance of MMS could be improved with dermoscopic assistance in post-laser BCC patients.