Mohs Micrographic Surgery
by Deanna M. Neff, MPH
This procedure is used to remove skin cancer that affects the face and other sensitive areas. The cancer is removed layer by layer. The tissue is examined under a microscope until only healthy tissue remains.
Reasons for Procedure
This surgery is most often used to treat basal and squamous cell carcinomas and other more rare skin cancers that:
This surgery is an effective and precise way to treat basal and squamous cell skin cancers. It offers a good chance for complete removal of the cancer, while sparing normal tissue.
Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, like:
Before your procedure, talk to your doctor about ways to manage factors that may increase your risk of complication, such as:
What to Expect
Prior to Procedure
In the time leading up to the procedure:
Local anesthesia will be used. You will not feel pain, but you will be awake during the procedure.
Description of Procedure
The area will be cleansed with antiseptic. A local anesthetic will be injected into the area. Using a small scalpel, the top visible portion of the cancer will be removed. Next, another, deeper layer will be removed. The layer will be divided into sections and examined under a microscope. Each section of the removed layer will be color coded. This will allow the doctor to know exactly where the layer was in the skin.
These sections will be frozen and examined under a microscope for remaining cancer cells. If cancer is found at the edges of the removed layer, the doctor will go back to the precise area where that section was removed. Additional layers will be removed and examined under a microscope until all areas are cancer free. For larger wound areas, the wound will be closed with stitches, a skin flap, or a skin graft procedure. Small, shallow wounds may heal without stitches.
How Long Will It Take?
You will have to wait while the tissue is examined under a microscope, which can take 30 minutes or more. In some cases, this procedure can last for several hours.
How Much Will It Hurt?
You should have minimal discomfort during the procedure. There will be some minor pain during recovery. You may be given pain medicine.
At the Care Center
During your stay, the hospital staff will take steps to reduce your chance of infection such as:
There are also steps you can take to reduce your chances of infection such as:
After the procedure, you may be given pain medicine and an antibiotic. You will be able to leave the same day.
Keep in mind that it is normal for a scar to form. The appearance may improve over time. The doctor will monitor your condition. You and your doctor will talk about prevention steps that include regular follow-up appointments and protecting your skin in the sun.
Call Your Doctor
Call your doctor if any of these occur:
If you think you have an emergency, call for emergency medical services right away.
American College of Mohs Surgery
American Society for Mohs Surgery
Canadian Association of Mohs Surgeons
Canadian Cancer Society
Mohs surgery. Encyclopedia of Surgery website. Available at:
...(Click grey area to select URL)
Accessed March 5, 2018.
Mohs surgery step by step. Skin Cancer website. Available at: https://www.skincancer.org/skin-cancer-information/mohs-surgery/step-by-step. Accessed March 5, 2018.
Special surgical techniques. American Cancer Society website. Available at: https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/surgery/special-surgical-techniques.html. Updated April 19, 2016. Accessed March 5, 2018.
6/6/2011 DynaMed's Systematic Literature Surveillancehttp://www.ebscohost.com/dynamed: Mills E, Eyawo O, et al. Smoking cessation reduces postoperative complications: a systematic review and meta-analysis. Am J Med. 2011;124(2):144-154.
Last reviewed March 2018 by EBSCO Medical Review Board Monica Zangwill, MD, MPH
Last Updated: 9/3/2021
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