Mohs' micrographic surgery of the head and neck.

Mohs' micrographic surgery, a method originally developed in the 1930s to remove contiguously spreading cutaneous cancers under precise microscopic control, has emerged as the most reliable method for removing certain primary, incompletely excised, and recurrent basal cell and squamous cell carcinomas. Indications for its use have expanded to include many other cutaneous and noncutaneous neoplasms. Usually done as an outpatient procedure and using local anesthesia, a layer of tissue is excised, mapped in relation to the site of removal, sectioned horizontally, and examined for the presence of residual tumor. This sequence is repeated, removing only tissue that contains residual tumor, until a margin completely free of cancer is reached. Extremely high cure rates are achieved, and surrounding tissue is maximally conserved for wound repair.