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Mohs Procedure for Skin Cancer

If you've been diagnosed with certain types of skin cancer, your SSM Health physician may recommend a Mohs procedure. This procedure is a precise surgical technique that removes thin layers of cancer-containing skin until only cancer-free tissue is left.

What is the Mohs Procedure?

Mohs micrographic surgery involves removing a skin cancer one layer at a time and examining these layers under a microscope immediately after they are removed. This allows for a close examination of each layer of skin to detect cancer cells. It also allows a minimal amount of tissue to be removed while ensuring complete removal of all the cancer cells in the area of the wound being treated.

The Mohs procedure is a two-step process – one to remove the skin cancer and the other to heal the wound. It is a lengthy procedure and treatment may take place over multiple days. It may also require more than one doctor visit at different locations. The initial procedure is usually performed on an outpatient basis in your SSM Health Dermatologist's office.

Preparation for the Procedure

The following general tips can help you prepare for a Mohs procedure. Always follow the specific tips provided by your health care team.

  • Stop the use of aspirin or aspirin-containing compounds (Anacin, Bufferin, Ascriptin, etc.) for two weeks prior to your visit.
  • If your doctor has prescribed the use of aspirin or a blood thinner such as Coumadin (Warfarin), or Plavix for an important condition such as heart disease, strokes, or clotting, DO NOT stop taking these medications without first consulting your doctor.
  • Stop non-steroidal anti-inflammatory agents for pain (Advil, Nuprin, Motrin, ibuprofen, etc.) seven days prior to surgery.
  • Stop Vitamin E and all herbal supplements at least two weeks before surgery, including but not limited to garlic, ginger, ginseng, feverfew, fish oils, flax seed, dong quai root, tumeric, hawthorne, ma huang, St. John’s Wort, bilberry, and gingko biloba.
  • Continue all other medications, including blood pressure medications and diuretics.
  • The night before surgery, or the morning of surgery, please use an antibacterial soap to wash the affected area to reduce the chance of infection.
  • Eat a good breakfast prior to your visit.
  • Wear comfortable clothing.
  • Come prepared with an activity to occupy your time during the process.

Steps to a Mohs Procedure

  • The affected area is injected with a local anesthetic (numbing agent).
  • A layer of tissue is removed and inspected under a microscope.  
  • The dermatologist will repeat the removal of tissue and the inspection of it multiple times, if needed, until no more cancer cells are detected in the area being treated.
  • This process may take course over multiple hours. Plan to spend most of your morning in in your physician's office.

Wound Repair

The size and shape of the wound depends upon the extent of the skin cancer. Though this cannot be predicted before surgery, it is typically several millimeters wider than the visible skin cancer.

In some areas of the face, small wounds may look best if allowed to heal on their own. Most defects, however, require at least a few small stitches. Larger wounds may need skin flaps or grafts. Both techniques involve moving healthy skin into the surgical wound. Unusually large or complicated tumors may, however, require consultation with another sub-specialist.

Unfortunately, the type of repair needed for your wound cannot be determined until the entire skin cancer is removed. Remember—the primary reason for Mohs Surgery is to cure the skin cancer. Once this is completed our physicians will help you to achieve the best cosmetic outcome possible.

After a Mohs Procedure

  • Pain after the procedure is generally mild and usually controlled with Tylenol.
  • You will receive written instruction on wound care from your doctor.
  • Activity restrictions may be necessary after your procedure per the surgeon's instructions.
  • If stitches are placed, a follow up appointment will be necessary for their removal.
  • Please note that any surgery will result in a scar. Most scars will diminish over a year's time. They will flatten out and lose their redness.
Remember, skin cancer can be treated when found early. If you have found a questionable spot on your skin, don't delay. Visit your primary care physician or dermatologist as soon as possible.

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