Impact of reflectance confocal microscopy on surgical outcomes in lentigo maligna and lentigo maligna melanoma: A retrospective cohort study of 282 patients.

Abstract

Lentigo maligna (LM) and its invasive form, lentigo maligna melanoma (LMM), often occur in sun-exposed areas and are characterized by subclinical extension, thereby complicating margin delineation. Reflectance confocal microscopy (RCM) has emerged as a non-invasive imaging tool for presurgical mapping of such lesions. To evaluate the impact of RCM on surgical outcomes in LM/LMM compared to standard clinical and dermoscopic assessment. We conducted a retrospective comparative cohort monocentric study by including 282 patients treated for LM or LMM between 2018 and 2025. Patients were divided into 2 groups: 184 who underwent presurgical RCM mapping (RCM group), and 98 who received standard care without RCM (non-RCM group). Surgical outcomes-including number of procedures, surgical margin, and recurrence rates-were compared between the groups. The rate of complete excision after a single procedure was significantly higher in the RCM group (63.6%) compared to the non-RCM group (34.7%, p < 0.0001). Patients in the RCM group required fewer surgical stages (mean 1.18 vs. 1.94; p < 0.0001) and narrower margins (mean 5.2 mm vs. 6.2 mm; p = 0.002). These benefits were especially notable in complex facial subregions. Median follow-up durations were comparable between the groups (1096.5 vs. 1167.5 days; p = 0.27). RCM-guided surgery improved margin control and surgical efficiency in LM and LMM, especially in anatomically complex regions. These results support the integration of RCM into routine preoperative planning for LM/LMM.