BASIC CONCEPTS

Mohs micrographic surgery may be considered the best local treatment option for cutaneous melanoma. The key benefits of Mohs surgery for the treatment of melanocytic lesions are its ability to completely assess the tumor margins and its ability to spare normal tissue when necessary. The first benefit is particularly relevant when treating lentigo maligna and lentigo maligna melanoma, lesions that often possess poorly defined clinical margins and a high local recurrence rate when treated by standard excisional surgery. The second benefit is relevant to specific anatomic areas where removal of standard surgical margins would be associated with significant cosmetic and/or functional morbidity such as eyelid margin, nasal alar rim, and other similar areas. Other clinical scenarios where Mohs surgery for the treatment of melanoma may be valuable include locally recurrent tumors, large-diameter tumors, poorly circumscribed tumors, amelanotic melanoma, and desmoplastic melanoma.

Developments in staining and immunohistochemical techniques have allowed better visualization of melanocytes in frozen skin sections. Modifications of the Mohs technique, including “slow-Mohs” and “wide-Mohs,” have been advocated by some as useful for the treatment of cutaneous melanoma. While controversies surrounding appropriate surgical margins and the adequacy of serial cross-sectioning of pathologic specimens continue, the need for complete en face examination of the surgical margins of melanocytic lesions is gaining recognition. The use of Mohs surgery does not negate the use of standard surgical margins (if desired) or further staging procedures.