Mohs Micrographic Surgery is the most effective and precise method of treatment for skin cancer removal when performed by a fellowship trained Mohs surgeon.  The outstanding cure rate, up to 99%, is related to the use of a microscope to establish the cancer free margins while preserving the maximum amount of healthy tissue and resulting in the smallest scar.

The fellowship trained Mohs surgeon combines the expertise of a dermatologist, pathologist, and reconstructive surgeon. The Mohs fellowship is of one or two years duration upon completion of a three year residency in dermatology. Prior to his dermatology residency and Mohs fellowship at Henry Ford Hospital in Detroit, Dr. Fortier was a four year resident in anatomical and clinical pathology at St. Francis Hospital and Medical Center in Hartford, Connecticut. He also completed a year of training in surgery and medicine as an intern at the Hospital of Saint Raphael in New Haven, Connecticut.

The Mohs Micrographic Surgery technique was developed by Frederic E. Mohs, M.D. some seventy plus years ago. Since then the procedure has evolved from an often lengthy inpatient hospital procedure to its more refined outpatient procedure performed in a matter of hours with local anesthesia. The procedure uses the Mohs surgeon’s dermatology expertise to identify the probable clinical outline of the skin cancer. The Mohs surgeon then removes the tumor with a tiny margin of normal surrounding tissue. This specimen is measured, mapped out, and divided into smaller sections which are labeled with different color dyes and processed in the Mohs dermatopathology laboratory in a very exacting process to make slides which are examined under the microscope by the Mohs surgeon.

 This microscopic examination evaluates I00% of the peripheral margins. If all of the peripheral margins are determined to be free of cancer or advanced precancerous changes under the microscope, the Mohs surgeon repairs the defect. If under the microscope the cancer is determined to extend beyond the margin of normal tissue surrounding the cancer, the Mohs surgeon identifies the extension site’s exact location.  This precision is possible because the Mohs surgeon labels, color codes and measures all of the areas. An additional small layer of tissue is removed at the site of the remaining tumor and the Mohs technique is repeated to make a new set of slides to evaluate the new margin. This procedure is repeated as necessary until all margins are determined to be cancer free. The Mohs surgeon then uses his expertise as a reconstructive surgeon to repair the defect.  As 100% of the excision margin is examined on slides under the microscope by the Mohs surgeon, the Mohs technique utilizes much smaller excision margins than any other method of treatment, resulting in a smaller final defect requiring a smaller closure with a smaller scar and a more pleasing cosmetic effect, as well as a reassuring cure rate of up to 99%.


Other Treatment Options

Mohs Micrographic Surgery is recognized  as the state of the art procedure for the removal of skin cancer.  Other options include curettage and electrodesiccation (scraping and burning off the cancer), and cryosurgery (freezing the cancer). Both methods have much higher recurrence rates than Mohs and result in significant visible scarring. Radiation therapy is another option, but it has a higher recurrence rate than Mohs and is a much more drawn out procedure requiring multiple visits over a period of weeks or months.  However, Dr. Fortier recommends radiation therapy in specific situations. The above three methods share a major disadvantage because they destroy both cancer and healthy tissue and leave no specimen for pathology examination. Therefore there is no objective way to establish complete tumor removal.

Yet another option is standard surgical excision. The excised cancer tissue is sent to a pathology laboratory in a hospital or independent location for pathology evaluation. As this standard pathology evaluation is not available immediately, and may take as long as a week or more for the surgeon to receive the pathology report, the surgeon closes the defect before knowing if the margins are free of cancer. If the pathology report comes back with an indication of cancer present at the margins, the patient must be scheduled for additional surgery. Another drawback of standard surgical excision is that the excised tissue cannot be processed using the Mohs technique, and is instead processed using standard pathology methods.

The method of standard pathology examination is unable to evaluate 100% of the peripheral excision margin, thus differing significantly from the Mohs technique which does evaluate 100% of the peripheral margins. Standard pathology examination evaluates only a portion of the peripheral margin (that portion represents only a fraction of the entire peripheral margin) and is therefore much less accurate than the Mohs method.

Dr. Fortier, in addition to being a dermatologist and a fellowship trained Mohs surgeon, is also a residency trained anatomical and clinical pathologist.  Dr. Fortier uses standard pathology methods for tumor diagnosis. He knows and understands (because he is trained in both methods) that only with the Mohs technique can the Mohs surgeon (who is also the pathologist) label and orient all excision margins during the actual surgical procedure therefore enabling exact tissue orientation resulting in total evaluation of 100% of the excision margins. While standard pathology methods are not the procedure of choice for evaluating peripheral margins in removing skin cancer tumors (Mohs is), standard pathology is the method of choice for diagnosis of tumors.



 Mohs Micrographic Surgery is primarily used to treat the most common skin cancers: basal cell carcinoma and squamous cell carcinoma. Mohs surgery is also used to treat:

  • locations of known high recurrence rate, such as nose, lips, orbits, mouth, and scalp
  • cosmetically significant areas such as face, neck, hands and feet
  • preservation of maximum function, such as face and extremities
  • recurring cancers
  • cancers developing in scar tissue
  • aggressively growing cancers
  • cancers where the margins cannot be clearly defined
  • large cancers
  • cancers in patients concerned with having the best cosmetic outcome

For more information about the American College of Mohs Surgery, click here.