Mohs Surgery

What is Mohs surgery?

Mohs surgery is a precise surgical technique used to treat several types of skin cancer. The goal of Mohs surgery is to remove all of the skin cancer leaving as much normal, healthy skin as possible. This technique is usually done on an outpatient basis using a local anesthetic.

During Mohs surgery, thin layers of cancer-containing skin are progressively removed and examined until only cancer-free tissue remains. Microscope slides of each piece of tissue are prepared and examined by the surgeon to verify that the skin cancer has been removed completely with a clear margin. 

Mohs surgery allows surgeons to verify that all cancer cells have been removed at the time of surgery. This increases the chance of a cure and reduces the need for additional treatments or additional surgery.

Why See a Dermatologists for Skin Cancer

Dermatologists are the experts in diagnosis and management of skin cancer. When skin cancers are identified and treated early, patients have the best chance for a good outcome.  

How Dermatologists Perform Mohs Surgery

Dermatologists trained in Mohs surgery are able to fulfill three important roles, as the surgeon who removes the cancerous tissue, as the pathologist who analyzes the tissue, and as the surgeon who closes or reconstructs the incision site. 

Initially, your doctor will take photographs and measurements of the skin cancer, and then a local anesthetic will be administered. When the area of skin is numb, the initial “layer” or “stage” is taken to remove all of the visible skin cancer with a thin rim of normal underlying tissue. The goal of each stage, including the first, is to remove the entire skin cancer with a clear margin. The tissue that is removed is then brought to the in-office laboratory where a histology technician prepares microscope slides of the removed skin cancer. Under the microscope, the physician can easily see if the have removed the entire skin cancer, or if they have cut through it. If so, an additional stage will need to be taken to again attempt to completely remove the cancer.

During the surgery, the dermatologist can see exactly where the cancer stops. This isn’t possible with other types of treatment for skin cancer. 

What to Expect at your Mohs surgery

Mohs surgery is performed in our outpatient clinic. In many cases, the procedure, tissue examination, and any surgical repair lasts a few hours, but since it can be difficult to tell how extensive a skin cancer is just by looking at it, we recommend you reserve the whole day for your procedure.

Dress in comfortable, layered clothing. You may be offered a gown if your skin cancer is under your clothing.  As described above, Mohs surgery is done in stages, including lab work, while the patient waits. While you wait you may sit in our guest lounge and watch television, read, or have a light snack. 

Expect to wait an hour or so until your tissue has been prepared and evaluated under the microsope. If more than one or two stages are needed to identify and remove all the cancer cells, the entire process may take several hours. This time is well worth it, as the precision involved in this procedure gives the highest cure rate of any treatment method while saving healthy tissue. 

Once the skin cancer has been removed completely with a clear margin, you and your doctor will discuss healing options for your surgical wound. Depending on the wound, these options can include:

  • Allowing the wound to heal on its own (secondary intention)
  • Using stitches to suture the wound closed
  • Moving local tissue from an adjacent area to cover the wound (flap repair)
  • Taking skin from another area to cover the wound (skin graft)

For wounds that are very large or complex, your surgeon may temporarily bandage your wound and refer you to another surgeon for reconstructive surgery.


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