Figure 1- The area to be treated is cleansed, marked, and injected with a local anesthetic.  The Mohs surgeon removes the visible cancer, along with a thin layer of additional tissue.  This procedure takes only a few minutes, and the patient waits while the tissue is processed and examined.

Figure 2 – Tissue cut in a saucer shape. The removed tissue specimen is cut into sections, stained, and marked on a detailed diagram called a Mohs map.

Figure 3 – The tissue is frozen on a cryostat, and a technician removes very thin slices from the entire edge and undersurface.  These slices are then placed on slides and stained for examination under a microscope. This is the most time-consuming portion of the procedure, often requiring an hour or more to complete.

Figure 4 – The Mohs surgeon carefully examines the entire undersurface and compete edge of the specimen, and all microscopic “roots” of the cancer are precisely identified and pinpointed on the Mohs map.  Upon microscopic examination, if residual cancer is found, the Mohs surgeon utilizes the Mohs map to direct the removal of additional tissue (Figure 2).  Note that additional tissue is removed only where cancer is present.

Figure 5 – This process is repeated as many times as necessary to locate any remaining cancerous areas within the tissue specimen (Figure 3, Figure 4, etc.)

Figure 6 – When microscopic examination reveals that there is no remaining tumor, the surgical defect is ready for repair.