Medical Dermatology

Skin Cancer (MOHS)

What is Mohs Micrographic Surgery?

Mohs micrographic surgery is a specialized, highly effective technique for the removal of skin cancer. The procedure was developed in the 1930s by Dr. Frederic Mohs at the University of Wisconsin and is now practiced throughout the world. Mohs surgery differs from other skin cancer treatments in that it permits the immediate and complete microscopic examination of the removed cancerous tissue, so that all “roots” and extensions of the cancer can be eliminated. Due to the methodical manner in which tissue is removed and examined, Mohs surgery has been recognized as the skin cancer treatment with the highest reported cure rate.

Special Qualifications of the Mohs Surgeon

Physicians performing Mohs surgery should have specialized skills in dermatology, dermatologic surgery, dermatopathology, and Mohs surgery. Basic and advanced training in Mohs surgery is available through selected Residency programs, specialized fellowships, observational preceptorships, and intensive training courses. In addition, the Mohs surgeon must have the required surgical and laboratory facilities and must be supported by a well-trained Mohs nursing and histotechnological staff.

Advantages of the Mohs Surgical Procedure

Some skin cancers can be deceptively large – far more extensive under the skin than they appear to be from the surface. These cancers may have “roots” in the skin, or along blood vessels, nerves, or cartilage. Skin cancers that have recurred following previous treatment may send out extensions deep under the scar tissue that has formed at the site. Mohs surgery is specifically designed to remove these cancers by tracking and removing these cancerous “roots.” For this reason, prior to Mohs surgery it is impossible to predict precisely how much skin will have to be removed. The final surgical defect could be only slightly larger than the initial skin cancer, but occasionally the removal of the deep “roots” of a skin cancer results in a sizable defect. The patient should bear in mind, however, that Mohs surgery removes only the cancerous tissue, while the normal tissue is spared.

Special Indications for Mohs Surgery

It is important to note that Mohs surgery is not appropriate for the treatment of all skin cancers. Mohs micrographic surgery typically is reserved for those skin cancers that have recurred following previous treatment or for cancers that are at high risk for recurrence. Mohs surgery also is indicated for cancers located in areas such as the nose, ears, eyelids, lips, hairline, hands, feet, and genitals, in which maximal preservation of healthy tissue is critical for cosmetic or functional purposes.

Insurance Coverage for Mohs Surgery

Most insurance policies cover the costs of Mohs surgery and the reconstruction of the resultant surgical defect. Please contact the billing department of your Mohs surgeon’s office if you have questions about insurance coverage or to see if your insurer requires you to have a referral from your primary care physician. You may need to contact your insurance company directly about benefits or coverage.

Patient Preparation for Surgery

You should provide your physician with a complete list of all medications (prescription, over-the-counter, vitamins and supplements). This is especially true regarding blood thinners, including aspirin, aspirin substitutes, herbal medicines and supplements. Your doctor may have other preoperative instructions. Pay special attention to these. Additionally, Mohs surgery on some areas may impair your ability to safely operate a motor vehicle. Discuss this with your doctor or his representative before your surgery.

Duration of Procedure

Most Mohs cases can be completed in three or fewer stages, requiring less than four hours. However, it is not possible to predict how extensive a cancer will be, as the extent of a skin cancer’s “roots” cannot be estimated in advance. Therefore, it is advisable to reserve the entire day for this surgical procedure, in case the removal of additional layers is required.

Minor Post-Surgical Discomfort Expected

Most patients do not complain of significant pain. If there is some discomfort, normally only Tylenol is required for relief. However, stronger pain medications are available and may be prescribed when needed. You may experience bruising, swelling and small amounts of bleeding around the wound. If any of these are severe, you should contact your surgeon.

Options for Post-Surgical Reconstruction

After the skin cancer has been removed, your Mohs surgeon will consider various repair options. These may include:

  1. Allowing the wound to heal without any additional surgical repair (“healing by secondary intention”).
  2. Wound repair performed by the Mohs surgeon.
  3. Repair by the original referring physician.
  4. Repair by another surgeon who might have a particular expertise regarding an anatomic area, repair type, special equipment, or skill regarding repair of inordinately
    large defects.

If your wound requires daily care at home, you will be given detailed instructions following your surgery. For small post- surgical sites, direct closure by suturing the sides of the wound together may be possible. However, in certain areas
of the body, there is very little tissue that can be stretched for coverage of a wound, and either a skin graft or skin flap must be used. In closing wounds with a skin flap, the skin adjacent to the surgical defect is partially cut free, and then rotated

or moved forward to cover the surgical area. Stitches are then placed to hold the flap in its new position. This provides immediate coverage for the wound. Other areas may require a skin graft to provide coverage. Skin from the side of the neck, behind the ear, or over the collarbone may be cut free, placed over the wound, and then sewn into place. The original site of the graft is then closed with stitches or allowed to heal on its own.

Wound Healing, Scarring, and Scar Revision

As with all forms of surgery, a scar will remain after the skin cancer is removed and the surgical area has completely healed. Mohs micrographic surgery, however, will leave one
of the smallest possible surgical defects and resultant scars. Often, wounds allowed to heal on their own result in scars that are barely noticeable. Even following extensive surgery, results are frequently quite acceptable. In addition, scars do have the ability, through the body’s own natural healing properties, to remodel and improve in appearance for a six to twelve month period. There are also many other techniques available to the patient for enhancement of the surgical area following skin cancer surgery. Depressed or indented scars may be elevated, using an implant such as Zyderm collagen. Likewise, a raised or roughened scar may be smoothed, using laser resurfacing or chemical peeling techniques. Skin flaps and grafts also may require a subsequent “touch up” procedure, to further improve their appearance.

Potential Complications Associated With Mohs Surgery

Patients should understand that there is not an absolute guarantee that any given procedure will be totally free of complications or adverse reactions. Mohs surgery is no exception. During surgery, tiny nerve endings are cut, which may produce a temporary or permanent numbness in and around the surgical area. If a large tumor is removed or extensive surgery is required, occasionally a nerve to muscles may be cut, resulting in temporary or permanent weakness in a portion of the face. This is, however, an unusual complication. The surgical area may remain tender for several weeks or months after surgery, especially if large amounts of tissue were removed. Rarely, some patients experience intermittent itching or shooting pain in the surgical area. In addition, the skin grafts and flaps used to cover surgical areas may not fully survive, requiring additional repair.

About the American Society for Mohs Surgery

The American Society for Mohs Surgery was established in 1990, and has experienced continued growth while honoring its commitment to the organization’s original tenets:

“The purpose of this organization shall be to promote the highest standards of patient care relating to Mohs surgery for the surgical removal of skin cancer and other appropriate malignancies; to establish quality assurance and regular peer review of Mohs surgeons; to provide a forum for the exchange of ideas and methodology for Mohs surgery and related basic sciences; to promote the professional education of its members and the medical community in the principles and practice
of Mohs surgery; to encourage research into all methods of microscopically controlled removal of malignant tissue; and to provide information for public education relating to
Mohs surgery.”

For additional information regarding the American Society for Mohs Surgery, its membership qualifications, and educational programs, please contact our administrative office or visit our Web site.


CoolSculpting | CoolSculpting Results | CoolSculpting Costs | PRP