Importance Lentigo maligna (LM) is a clinical, pathologic, and therapeutic challenge with a higher risk of local recurrence than other types of melanoma correctly treated and also carries the cosmetically sensitive localization of head and neck.
Objective To determine whether in vivo reflectance confocal microscopy (RCM) mapping of difficult LM cases might alter patient care and management.
Design Analysis of LM and LM melanoma (LMM) in a series of patients with large facial lesions requiring complex reconstructive surgery and/or recurrent or poorly delineated lesions at any body sites were investigated.
Settings Two tertiary referral melanoma centers in Sydney, Australia.
Participants Thirty-seven patients with LM (including 5 with LMM) were mapped with RCM. Fifteen patients had a recurrent LM, including 9 with multiple prior recurrences. The LM was classified amelanotic in 10 patients, lightly pigmented in 9, and partially pigmented in 18.
Interventions The RCM images were obtained in 4 radial directions (allowing for anatomic barriers) for LM margin delineation using an RCM LM score previously described by our research team.
Main Outcome Measures Differences in the margin of LM as determined by RCM vs dermoscopy vs histopathologic analysis.
Results Seventeen of 29 patients (59%) with dermoscopically visible lesions had subclinical (RCM-identified) disease evident more than 5 mm beyond the dermoscopy margin (ie, beyond the excision margin recommended in published guidelines). The RCM mapping changed the management in 27 patients (73%): 11 patients had a major change in their surgical procedure, and 16 were offered radiotherapy or imiquimod treatment as a consequence of the RCM findings. Treatment was surgical in 17 of 37 patients. Surgical excision margins (based on the RCM mapping) were histopathologically involved in only 2 patients, each of whom had an LM lesion larger than 6 cm.
Conclusions and Relevance In vivo RCM can provide valuable information facilitating optimal patient care management.