Epidemiology and characteristics of acral lentiginous melanoma compared to lentigo melanoma in France: a multicentric retrospective study from the French cohort RIC-Mel database

Background Skin phototype, latitude and sun exposure are classic risk factors for melanomas but are not relevant to acrolentiginous melanomas (ALM). ALM is not related to chronic sun exposure because the thick stratum corneum acts as a barrier to penetration of UV rays, whereas LMM occurs in skin with high photoaging due to chronic sun exposure. Objectives This study aimed to determine if any difference exists between “solar” melanomas and “non-solar” melanomas based on a comparison between LMM and ALM. Materials & Methods We extracted all data for ALM and LMM patients, from March 2012 to September 2020, from the RIC-Mel national database to perform a descriptive cohort analysis of 1,056 Caucasian cases. Conclusion The profiles of solar-related and non-solar melanoma seem to be different, and prognostic factors of ALM at diagnosis are less favourable compared to LMM, suggesting that non-solar melanoma is more aggressive than solar-related melanoma and that sentinel lymph node biopsy should be performed.