Surgical management of melanoma in situ on chronically sun-damaged skin.

BACKGROUND: Lentigo maligna (LM) commonly presents as a slow-growing pigmented macular lesion in chronically sun-damaged skin and may progress to invasive melanoma. Many regard it as a subtype of melanoma in situ (MIS), and surgical excision remains the preferred treatment, but standard 5-mm surgical margins recommended for typical MIS are often insufficient for LM due to its indistinct borders both clinically and histologically.
METHODS: A search of the literature was conducted to review specialized surgical techniques for the treatment of LM, focusing on methods that employ total peripheral margin assessment prior to definitive closure, using either frozen or permanent histologic sections.
RESULTS: Many investigators have reported surgical modalities utilizing permanent sections for margin control, including variations of the "square" procedure and "perimeter" technique. Recurrence rates are low with these methods, but only short-term data have been reported. Similarly, several studies have demonstrated the efficacy of Mohs micrographic surgery (MMS) for treatment of MIS, with recurrence rates generally less than 1% over 3 to 5 years of follow-up. Many investigators have had success with immunohistochemical stains to identify melanocytes on frozen sections, aiding margin assessment in MMS.
CONCLUSIONS: Compared to standard excision, methods that employ surgical margin control offer superior cure rates for LM and should be utilized when available. Total peripheral margin assessment using staged excisions and permanent sections is a simple and effective alternative to MMS for institutions that lack the resources for intraoperative frozen section analysis.