After the removal of the visible portion of the tumor by excision or curettage (debulking), there are two basic steps to each Mohs Micrographic Surgery stage. First, a thin layer of tissue is surgically excised from the base of the site. This layer is generally only1-2 mm larger than the clinical tumor. Next, this tissue is processed in a unique manner and examined under the microscope. On the microscopic slides the doctor examines the entire bottom surface and outside edges of the tissue. (This differs from the frozen sections prepared in a hospital setting which, in fact, represent only a tiny sampling of the tumor margins.) This tissue has been marked to orient top to bottom and left to right. If any tumor is seen during the microscopic examination, its location is established, and a thin layer of additional tissue is excised from the involved area. The microscopic examination is then repeated. The entire process is repeated until no tumor is found.

Mohs Micrographic Surgery allows for the selective removal of the skin cancer with the preservation of as much of the surrounding normal tissue as is possible. Because of this complete systematic microscopic search for the roots of the skin cancer, Mohs Micrographic Surgery offers the highest chance for complete removal of the cancer while sparing the normal tissue. The cure rate for new basal cell and squamous cell carcinomas exceeds 97%. As a result, Mohs Micrographic Surgery is very useful for large tumors, tumors with indistinct borders, tumors near vital functional or cosmetic structures, and tumors for which other forms of therapy have failed. Although no surgeon or technique can guarantee 100% chance of cure, the Mohs technique enjoys the highest cure rate of all treatments for selected skin cancers.