Mohs micrographic surgery for nonmelanoma skin cancer

Mohs micrographic surgery is a technique by which skin cancers are excised with complete, three-dimensional microscopic control of all surgical margins, allowing the detection and excision of all subclinical tumor extensions. Successive layers of tissue are removed, and the entire undersurface and peripheral epidermal edge are examined histologically, typically with frozen sections.(1-3) This approach is ideally applied to skin cancer excision, because most lesions grow in a contiguous fashion. Consequently, microscopic extensions, which often extend well beyond the clinically apparent margins,(4) can be detected and traced out after microscopic examination of the entire surgical margin. The precise nature of the technique also allows the preservation of uninvolved tissues and obviates removal of predetermined margins of clinically normal skin.