Because skin cancer cells often have spread beyond the edges of the visible patch on the skin, dermatologists sometimes use a special surgical technique to make sure they remove all of the cancer. In this technique, called Mohs microscopically controlled surgery or Mohs micrographic surgery, dermatologists first remove the visible tumor and then begin cutting away the edges of the wound bit by bit. During surgery, the dermatologist examine pieces of tissue to look for cancer cells. Tissue removal from the area continues until the samples no longer contain cancer cells. This procedure enables dermatologists to limit the amount of tissue removed and thus is especially useful for removing cancers near such delicate sites as the eye.

After removing all of the cancer, dermatologists decide how best to replace the skin that has been cut away. They may bring the edges of the remaining skin together with sutures or use a skin graft or skin flap. Or they may place a dressing on top of the wound and let the skin heal on its own.

Mohs surgery reduces recurrence rates for skin cancers. This surgery is useful for basal cell and squamous cell cancers but is less often used for melanoma.