Mohs Micrographic Surgery

What is Mohs surgery?

Mohs micrographic surgery was developed by Dr. Frederick Mohs in the 1930s. It is the most effective surgical treatment for removing basal cell carcinoma and squamous cell carcinoma.

During this procedure, skin cancer is removed layer by layer. Each layer of tissue is looked at under a microscope until the margins are clear. Clear margins means that the edges of the tissue removed are free of cancer cells when looked at under a microscope. Using a microscope provides a precise method for removing cancerous tissue. It also helps spare more healthy tissue and prevents the need for more surgery. 

Mohs surgery may result in smaller surgical defects and less scarring, as compared to other surgical methods to remove skin cancer. The Mohs procedure is used for skin cancer removal in areas where preserving healthy tissue is needed for cosmetic and functional purposes (i.e. face, scalp, etc).

How is it done?

The Mohs procedure is often done as an outpatient, meaning that you don’t have to be admitted to the hospital. The office where you have the procedure done will have a surgical area and a laboratory so that the tissue can be checked for cancer cells on-site. It is often done in one day. 

The steps to the Mohs procedure are as follows:

• The surgeon will look at the lesion and plan how much tissue to remove. They may draw on your skin and take pictures. The goal is to remove the roots of the cancer to prevent it from coming back.
• A local anesthetic is put on or injected into the skin. A local anesthetic numbs only the surgical area. Tell your provider if you are having pain. The area will also be cleaned and drapes may be placed around the area. 
• The surgeon will remove the part of the tumor they can see with surgical tools.
• Next, a deeper layer of skin is removed and cut into sections. Each section will be color-coded with dye that matches up with a mark left on the skin to show where each section of the skin was removed. A surgical site map will be drawn to track where each piece of the tissue came from.
• A specialist will look at each part of the skin under a microscope for any cancer cells.
• If cancer cells are found on any pieces of tissue under the microscope, the surgeon will mark the location on the map and will remove another layer of tissue from that area of your skin.
• The removal process will continue until no cancer cells are seen from any removed sections of skin. 
• The surgeon will decide what type of reconstruction will be needed to heal the site. Some incisions will heal on their own, known as secondary-intention healing. A larger wound may be closed with stitches. An even larger wound may need a skin graft from another part of the body or a skin flap, which uses skin next to the Moh’s site to cover the wound. You may need to be seen by a reconstructive surgeon if these techniques won’t close the wound. 
• You will be given time to rest, and you will be given instructions to follow at home.

It is normal for some patients to have discomfort, bleeding, redness, and inflammation. These can be easily managed and will go away.

What will my care be like after the procedure?

Your provider will give you instructions about caring for your incision. These may include:

• How to clean the surgical site and how to change the bandages (dressing). 
• Prescriptions and/or information about medications and topical ointments to use while your skin heals.
• Timeline, including when you can return to activities like exercising.
• Schedule for follow-up appointments to monitor healing and remove any stitches.
• Instructions for treating the scar to promote healing and fading.

If you are having any pain or bleeding that is not going away, you should call your provider. If you have any new changes to your skin, you should call your provider.