Mohs surgery

Mohs surgery is a surgical technique used primarily for the removal of skin cancers, particularly those with a high risk of recurrence or located in cosmetically sensitive areas like the face. This procedure involves removing layers of cancerous skin cells until only healthy, non-cancerous tissue is reached. It’s considered one of the most effective methods for treating basal cell carcinoma, squamous cell carcinoma, and melanoma.

This type of surgery can also be used to remove rare or high-risk skin cancers that occur on the trunk and extremities and for certain non-cancerous conditions involving the skin.

At Penn Medicine, our experienced Mohs surgeons have successful surgical track records that cover decades of medical practice. In addition, our state-of-the-art Mohs surgery unit is equipped with on-site laboratories that process surgical specimens, allowing for real-time microscopic evaluation and immediate results for our patients. 

Mohs surgery uses microscopic guidance to ensure that all the problematic cells are removed. The precision of the Mohs technique helps decrease scarring by removing all the diseased skin while leaving behind as much healthy skin as possible.

It works by removing skin with problematic cells one layer at a time. The skin is examined under a microscope to determine if the cells extend to the edge of the sample. If so, the surgeon removes another thin layer of tissue and repeats the process until no signs of problematic cells remain.

In most cases, the Mohs surgeon immediately repairs the wound with stitches. Larger wounds may require a flap by rearranging skin near the wound, or a graft that borrows skin from another site to cover the wound. In certain cases, the surgeon may recommend letting the wound heal on its own to achieve the best appearance. 

Mohs surgery is recommended for patients diagnosed with skin cancers that exhibit the following appearance or characteristics:

• Large in size 
• Poorly defined edges 
• Returned after previous treatments 
• Grew on areas of the body where it’s important to keep the surgical incision as small as possible to avoid scarring and maintain function

Beyond its primary use in skin cancer treatment, Mohs surgery is sometimes used for certain non-cancerous conditions, particularly those involving the skin. While these instances are less common, Mohs surgery may be used for: 

• Dermatologic conditions like removing cysts or lipomas in cosmetically sensitive areas.  
• Complex or recurrent non-cancerous skin lesions like sebaceous adenomas or dermatofibromas. 
• Micrographic surgery for precancerous lesions such as Bowen’s disease, also known as squamous cell carcinoma in situ. 
• Scar revision and reconstruction to help improve the appearance and function of scars resulting from trauma, surgery, or other causes. 

On the day of your procedure, you can expect the following:

• Your procedure will be done in a doctor’s office or outpatient surgical center.
• You’ll be fully awake during the procedure. Your skin will be numbed with anesthesia, and you may feel pressure in the area, but you won’t feel any pain. Your Penn Medicine care team will be by your side the entire time to make sure you’re comfortable.
• Your surgeon will remove a thin layer of tissue while leaving as much healthy skin as possible.
• Your surgeon will look at the tissue under a microscope to see if all the problematic cells have been removed. If needed, this process is repeated until your sample is clear. 
• You’re likely to undergo the reconstruction portion of your surgery immediately after the Mohs procedure.
• Most patients go home on the same day as the procedure. It’s recommended that a friend or family member drive you home.

After a Mohs procedure, most patients have minimal pain. Our clinical staff will explain and demonstrate how to care for your wound. You’ll also receive written instructions and information for contacting your Penn Medicine Mohs surgeon in the rare case of an emergency. You’ll return in one to two weeks to have your stitches removed and to ensure that the wound is healing well.

To protect the wound, you should avoid strenuous activities for at least one week after surgery. You may experience swelling, redness, and bruising for one or two weeks, especially if the procedure was done on your forehead, eyes, nose, or lips.

After Mohs surgery, most patients heal well and don’t require additional treatment for their scars. However, if you have questions about the scarring or healing process, don’t hesitate to contact your care team to discuss other options for cosmetic improvement.

We’re experts in removing skin cancer and performing other dermatological procedures using Mohs micrographic surgery. Our surgeons are board-certified and have completed advanced training through the American College of Mohs Surgery.

Mohs surgery at Penn Medicine offers those with skin cancer of the face, head, or neck the following advantages:

• Immediate microscopic evaluation during the procedure, which confirms that the skin cancer is completely removed.
• The highest published cure rates for many forms of skin cancer, making it less likely the cancer will grow back. 
• Maximum preservation of healthy skin for the best possible cosmetic and functional results.