Mohs Micrographic Surgery

Mohs micrographic surgery, an advanced treatment procedure for skin cancer, offers the highest potential for recovery—even if the skin cancer has been previously treated. This procedure is state-of-the-art treatment in which the physician serves as surgeon, pathologist and reconstructive surgeon. It relies on the accuracy of a microscope to trace and ensure removal of skin cancer down to its roots. This procedure allows dermatologists, trained in Mohs Surgery, to see beyond the visible disease, and to precisely identify and remove the entire tumor, leaving healthy tissue unharmed. This procedure is most often used in treating two of the most common forms of skin cancer: basal cell carcinoma and squamous cell carcinoma.

The cure rate for Mohs micrographic surgery is the highest of all treatments for skin cancer—up to 99 percent even if other forms of treatment have failed. This procedure, the most exact and precise method of tumor removal, minimizes the chance of regrowth and lessens the potential for scarring or disfigurement.

The Mohs Surgeon

Surgeons that perform Mohs micrographic surgery are specialists both in dermatology and pathology. With their extensive knowledge of the skin and unique pathological skills, they are able to remove only diseased tissue, preserving healthy tissue and minimizing the cosmetic impact of the surgery. 

Indications for Mohs Surgery

Mohs micrographic surgery is primarily used to treat basal and squamous cell carcinomas, but can be used to treat less common tumors including melanoma. Mohs surgery is indicated when:

  • the cancer was treated previously and recurred
  • scar tissue exists in the area of the cancer
  • the cancer is in an area where it is important to preserve healthy tissue for maximum functional and cosmetic result, such as eyelids, nose, ears, lips
  • the cancer is large
  • the edges of the cancer cannot be clearly defined
  • the cancer grows rapidly or uncontrollably

Mohs Procedure

The Mohs process includes a specific sequence of surgery and pathological investigation. Mohs surgeons examine the removed tissue for evidence of extended cancer roots. Once the visible tumor is removed, Mohs surgeons trace the paths of the tumor using two key tools:

  • a map of the surgical site
  • a microscope

Once the obvious tumor is removed, the Mohs surgeon:

  • removes an additional, thin layer of tissue from the tumor site
  • creates a "map" or drawing of the removed tissue to be used as a guide to the precise location of any remaining cancer cells
  • microscopically examines the removed tissue thoroughly to check for evidence of remaining cancer cells

If any of the sections contain cancer cells, the Mohs surgeon:

  • returns to the specific area of the tumor site as indicated by the map
  • removes another thin layer of tissue only from the specific area within each section where cancer cells were detected
  • microscopically examines the newly removed tissue for additional cancer cells
  • If microscopic analysis still shows evidence of disease, the process continues layer-by-layer until the cancer is completely gone.

This selective removal of only diseased tissue allows preservation of much of the surrounding normal tissue. Because this systematic microscopic search reveals the roots of the skin cancer, Mohs Surgery offers the highest chance for complete removal of the cancer while sparing the normal tissue. Cure rates exceed 99 percent for new cancers, and 95 percent for recurrent cancers.

In the News

Naomi Lawrence, MD, Dermatologic Surgeon, explains the effectiveness of Mohs surgery: cbsnews.com, January 5, 2023

Contact Us

For an appointment with a surgeon who is an expert in Mohs micrographic surgery, please call 800.8.COOPER (800.826.6737).