MELANOMA in situ (MIS) is often considered a precursor to invasive melanoma, and its management typically involves wide local excision to ensure complete removal. However, questions remain regarding the necessity of such an approach in non-lentigo maligna (non-LM) and non-acral lentiginous (non-ALM) subtypes, where the risk of recurrence may be lower.
A retrospective cohort study from the Skin Cancer and Melanoma Unit at Andreas Sygros University Hospital in Athens, Greece, explored recurrence patterns and outcomes in patients with non-LM/non-ALM MIS. The study included 401 patients with 403 lesions, treated between 1991 and 2023, and followed up for a median of 5.2 years, with some patients monitored for up to 26 years. The majority of lesions were found on the trunk, with others on the extremities or head and neck.
All patients initially underwent excisional biopsy, and most proceeded to wide excision. Strikingly, during long-term follow-up, no local recurrences, metastases, or melanoma-related deaths were observed in cases where histopathological margins were clear. The only recurrence occurred in a patient with involved margins who did not undergo further excision, later developing invasive melanoma.
Importantly, patients with clear margins from excisional biopsy alone, who did not undergo wide excision, showed no recurrence after a median of more than eight years. Similarly, those treated with wide excision using narrower than standard margins also remained free of recurrence. A small number of suspicious lesions near excision sites were investigated during follow-up, but histopathology revealed only benign changes such as solar lentigo or nevus.
These findings suggest that in non-LM/non-ALM MIS, excisional biopsy with clear margins may be sufficient treatment, potentially sparing patients the morbidity associated with wider excisions. Nevertheless, the authors emphasise that larger studies are needed before changing practice, and comparisons with current standard management remain essential.
Reference
Dessinioti C et al. Local Recurrence and survival in patients with melanoma in situ. JAMA Dermatol. 2025;DOI:10.1001/jamadermatol.2025.3078.
