Histologic margin status is a predictor of relapse in lentigo maligna melanoma.

Most surgical margins for lentigo maligna melanomas reported in the literature are clinical and not histologic. We sought to determine whether histologic margin status is an independent predictor of progression. Clinicopathologic information of 268 invasive lentigo maligna melanomas diagnosed from 1990-2019 were analyzed. Statistical analyses were performed using Cox proportional hazards model and Boruta method. A total of 75% of the lesions were located on the head and neck. The range of follow-up for all patients was 0 to 31.8 years (median, 10.2 years). Time to local recurrence ranges from 0 to 20 years (median, 3 years). Progression developed in 54 (20.1%) of 268 patients. Local recurrence was seen only in 36 (13.4%), both local recurrence and subsequent metastasis in 7 (2.6%), and only metastasis in 11 (4.1%) of 268 patients. Histologic margin status (positive and close/<3 mm) and tumor site (head and neck location) significantly correlated with worse progression-free survival. Single institution and retrospective study. Histologic margin status is the strongest predictor of progression for lentigo maligna melanoma. Patients with positive or close/<3 mm histologic margins should consider a re-excision due to the increased risk of relapse. [ABSTRACT FROM AUTHOR]