Dr. Frederic Mohs developed "chemosurgery" in the late 1930's to treat skin cancer. He created a zinc chloride paste that was applied to the skin lesion overnight. The paste would kill the tissue and fix the cells to a controlled depth. The following day, Dr. Mohs would remove the dead tissue and evaluate the tissue sections microscopically to determine if all of the cancer was removed. Dr. Mohs combined the use of chemicals and surgery to treat cancer (chemosurgery) for many years. This unique Mohs procedure evolved and by the 1970's the chemical paste was no longer used, but frozen sections of fresh skin tissue remained a standard. The Mohs procedure continues to be a rapid-evaluation surgical procedure that can be completed in one day, from beginning to end.
Since that time, the Mohs procedure has become more precise in an effort to spare healthy skin from excision. Mohs microsurgery is most often employed to remove skin cancer from delicate and cosmetically sensitive areas of the face, head, and neck. Mohs is considered to have the highest skin cancer cure rate (above 98%) due to its precise mapping and margin evaluation.