Staged margin control techniques for surgical excision of lentigo maligna

Abstract

For melanoma in situ (MIS) arising in chronically photodamaged skin (a.k.a. lentigo maligna, LM), the preferred treatment remains surgical excision. Yet, the standard 5-mm margins of excision recommended for other subtypes of MIS have proven insufficient for LM, due to the its indistinct borders. In this report, authors review specialized surgical techniques for the treatment of LM that focus on meticulous assessment of peripheral margins prior to closure (staged margin control) conducted with analysis of either frozen or permanent histologic sections. Techniques utilizing permanent sections include variations of the ''square'', ''perimeter'', and ''contoured'' excisions, and recurrence rates with these techniques are reportedly low based on short-term follow-up. Similarly, Mohs micrographic surgery (MMS) has been reported to be effective in LM, with recurrence rates generally less than 1% over three-five years of follow-up. In order to simplify margin assessment for MMS, many investigators have begun to rely on intraoperative immunohistochemistry (IHC) to identify melanocytes in frozen sections, and MART-1 is surrently the preferred immunostain for this purpose. Other methods of IHC are currently under investigation. Regardless, surgical methods that employ this degree of margin assessment offer superior cure rates compared to standard excision, and should be seriously considered when encountering patients with LM. Total peripheral margin assessment using staged excisions and analysis of permanent sections appears to be a simple and effective alternative to MMS, especially for institutions that prefer examination of permanent sections to frozen sections.