Mohs Micrographic Surgery is a specialized procedure for the removal of skin cancers. The procedure is named after the originator of the technique, Dr. Frederick Mohs. The following information is intended to help you understand what Mohs Micrographic Surgery is and why it is recommended for the treatment of your skin cancer.


Skin cancer is by far the most common malignant tumor in humans. The most common types of skin cancer are Basal Cell Carcinoma, Squamous Cell Carcinoma and Melanoma. Both Basal Cell Carcinoma and Squamous Cell Carcinoma begin as a single point in the upper layers of the skin and slowly enlarge, spreading both along the surface and downward. These extensions cannot always be directly seen. The tumor often extends far beyond what is visible on the surface of the skin. If not completely removed, both types of skin cancer may invade and destroy structures in their path. Although these skin cancers are locally destructive, they do not tend to metastasize (spread) to distant parts of the body. With Basal Cell Carcinoma metastasis is extremely rare and usually occurs only in the setting of long-standing large tumors. Squamous Cell Carcinoma is slightly more dangerous and patients must be observed for any spread of the tumor. Such spread is still infrequent. Melanoma is a very different and more dangerous kind of skin cancer and will not be considered in this brochure.

Excessive exposure to sunlight is the single most important factor associated with the development of skin cancers. In addition, the tendency to develop these cancers appears to be hereditary in certain ethnic groups, especially those with fair complexions and poor tanning abilities. Fair-skinned people develop skin cancers more frequently than dark-skinned people and the more sun exposure they receive, the more likely they are to develop a skin cancer. Other factors, including exposure to radiation, trauma and exposure to certain chemicals, may also be involved in the development of skin cancers.


 In the past, Mohs Micrographic Surgery was sometimes called chemosurgery or Mohs chemosurgery. Originally, chemicals were applied to the skin during the surgery and hence, the name chemosurgery. Chemicals are now rarely used but the name chemosurgery continues to be associated with the procedure.

After the removal of the visible portion of the tumor by excision or curettage (debulking), there are two basic steps to each Mohs Micrographic Surgery stage. First, a thin layer of tissue is surgically excised from the base of the defect created by the debulking. Next, this tissue is processed and examined underneath the microscope. On the microscopic slides, the physician examines the entire bottom surface and the outside edges of the tissue removed. The tissue has been marked to orient top to bottom and left to right. If any tumor is seen during the microscopic examination, its location is established and a thin layer of additional tissue is excised from the involved area. The microscopic examination is then repeated. The entire process is repeated until no tumor is seen on the microscopic examination. Mohs Micrographic Surgery allows for the selective removal of the areas involved with the skin cancer with the preservation of as much of the surrounding normal tissue as is possible. Because of this complete systematic microscopic search for the "roots" of the skin cancer, Mohs Microscopic Surgery offers a 97-99% chance for complete removal of cancer without an excessive loss of normal tissue. As a result, Mohs Microscopic Surgery is very useful for large tumors, tumors with indistinct borders, tumors near vital functional or cosmetic structures, and tumors for which other forms of therapy have failed. However, no surgeon or technique can guarantee a 100% chance of cure.


The preoperative visit allows the doctor the opportunity to examine your skin cancer, obtain your medical history and determine whether the technique of Mohs Micrographic Surgery is the most appropriate way of treating your skin cancer. It also gives you the opportunity to meet Dr. Stasko and his staff and learn about the procedure. The skin cancer and surrounding tissue will be photographed before the treatment, as well as during and immediately after the surgery and again after healing. These photographs become part of your medical record and may be used for teaching purposes.

Mohs Microscopic Surgery utilizes a team approach. Our staff consists of a full-time staff surgeon, Dr. Thomas Stasko, a dermatology resident, nurses and technicians. All will be directly involved with your care during the surgery. The surgery is performed either in our clinic operating rooms at Vanderbilt University Medical Center.


Be well rested and eat a good breakfast. Take your usual medications, unless directed otherwise. Unless it is part of a physician-directed program, do not take any aspirin or aspirin containing products, such as Anacin or Bufferin, for two weeks prior to the surgery. In addition, please do not take Ibuprofin (Motrin, Advil, etc.). These medications "thin" your blood and may cause more bleeding. You may substitute acetaminophen (Tylenol) if required. Do not drink any alcoholic beverages or engage in strenuous exercise for 24 hours before surgery.

Bathe as usual and shampoo your hair the night before surgery, as your wound and initial dressing have to remain dry for 24 hours after surgery. You should arrange to have someone drive you home after the surgery. The length of the surgery varies dependent on the size and location of the skin cancer and the type of reconstruction to be done. Although the average length of time is approximately 3-4 hours, you should plan on spending most of the day. We ask that you limit the number of people accompanying you to 1 or 2 persons because of the limited space in our waiting room.


Appointments for surgery are scheduled through the day as is felt to be appropriate to the anticipated complexity of each case. You will be told when to arrive for your scheduled appointment. When you arrive for surgery, you will change into hospital clothing if necessary. It is a good idea to wear loose-fitting clothing and to avoid any "pullover" clothing. Before moving to the operating room, the doctor will again discuss the procedure with you and obtain your written consent for the procedure. If you have any additional questions, please feel free to ask them at this time.

Once you are in the operating room, we will cleanse the area surrounding your skin cancer with a sterile antibacterial soap, and we will place several sterile drapes over you. In addition, a sticky pad will be placed on your arm or leg to providing grounding for the electrosurgical unit (this machine is used to stop bleeding). The doctor will then anesthetize (numb) the area of skin containing the cancer by a small local injection (needle). This injection will probably be similar to the one you received when your biopsy was taken. After the tissue has been removed, it will be processed in our laboratory next to the operating room. It usually takes 30-45 minutes to anesthetize the involved area and remove the tissue.

Depending upon the amount of tissue removed, processing usually takes an additional 30-45 minutes. You will be asked to remain in the operating room while the tissue is processed for examination, stained, and examined by the doctor. If the microscopic examination of the removed tissue reveals the presence of additional tumor, we will go back and remove more tissue. Most skin cancers are removed in two or three surgical stages.


After the skin cancer has been completely removed, a decision is made on the best method for treating the wound created by the surgery. These methods include letting the wound heal by itself, closing the wound in a side to side fashion with stitches, and closing the wound with a skin graft or a flap. During the preoperative visit, the methods which might be appropriate to your case will be discussed with you; however, in most cases, the best method is determined on an individual basis after the final defect is known. We may complete your reconstruction or other surgical specialists may be utilized for their unique skills. We individualize your treatment to achieve the best results.

When the reconstruction is completed by other surgical specialists, that reconstruction may take place on the same day or a subsequent day. You will have already met the doctor who is to perform your reconstruction and you will know of the scheduling. There is no harm in delaying the reconstruction for several days. If the reconstruction is to be extensive, that portion of the operation may require hospitalization. Occasionally, a tumor may turn out to be much larger than was initially anticipated. Under those circumstances, other surgical specialists may become involved after the procedure has begun.


Your surgical wound will likely require wound care during the week(s) following surgery. Detailed written instructions will be provided after the completion of the surgery. You should plan on wearing a dressing and avoiding strenuous physical activity for 1-2 weeks. Most of our patients report minimal pain which responds readily to Tylenol. You may experience a sensation of tightness across the area of surgery. Skin cancers frequently involve nerves and months may pass before your skin sensation returns to normal. In some cases, numbness may be permanent. You may also experience itching after your wound has healed. Complete healing of the surgical scar takes place over 12-18 months. Especially during the first few months, the site may feel "thick", swollen, or lumpy and there may be some redness. Gentle massage of the area (starting about 1 month after surgery) and keeping the area lubricated with lotion will speed the healing process.

An indefinite follow-up period of observation is necessary after the wound has healed. You will be asked to return in three months, six months, one year, and at least annually thereafter. Studies have also shown that once you develop a skin cancer, there is a strong possibility that you will develop other skin cancers in the years ahead. Should you notice any suspicious areas, it is best to check with your physician for a complete evaluation.

Sunshine is not harmful to you as long as you use adequate protection. Fifteen to thirty minutes before sun exposure, you should liberally apply a sunscreen with a sun protection factor (SPF) of 15 or higher to all exposed areas. Since many sunscreens wash off with water or perspiration, reapply it liberally after swimming or exercising. In addition to a sunscreen, wear a broad-brimmed hat and utilize clothing to further protect yourself from the sun. Remember, sun exposure is most intense between 10AM and 3PM. You may lead a normal lifestyle if you take precautions and are sensible.


Because each patient is unique, it is impossible to discuss all the possible complications and risks in this format. Below are discussed the general risks associated with many of these procedures. The doctor will discuss these matters with you and any additional potential problems associated with your particular case.

  • The defect created by the removal of the skin cancer may be larger than anticipated. The ability to "track" the extent of the tumor is actually an advantage of the Mohs method. However, the tumor may be much larger than estimated from the surface appearance. There is no way to predict prior to surgery the exact size of the final defect.
  • There will be a scar at the site of removal. We will make every effort to obtain optimal cosmetic results, but our primary goal is to remove the entire tumor. The cosmetic outcome cannot be guaranteed.
  • There may be poor wound healing. At times, in spite of our best efforts, for various reasons (such as bleeding, poor overall physical condition, diabetes, or other disease states), healing is slow or the wound may reopen. Flaps and grafts utilized to repair the defect may at times fail. Under these circumstances, the wound will usually be left to heal on its own.
  • There may be a loss of motor (muscle) or sensory (feeling) nerve function. Not infrequently the tumor invades nerve fibers. When this is the case, the nerves must be removed along with the tumor. At other times, the tumor, or the tissue moved in the reconstruction of the defect, is adjacent to nerve fibers. At these times, nerves may also be severed or injured. If a sensory nerve is injured or removed, numbness results. Sensation will usually, but not always, return. It may take up to 24 months for sensation to return. If a motor nerve is involved, you may be unable to move the muscle that that nerve served. An example of this would be the inability to wrinkle your forehead. In most, but not all circumstances, this nerve function will return over a prolonged period of time. If a major motor nerve has been involved, microsurgical repair may be required. Prior to your surgery, the doctor will discuss with you any major nerves which might be near your tumor.
  • The tumor may involve an important structure. Because tumors often occur on the head and neck, many are near or on vital structures such as the eyes, nose or lips. If the tumor involves these structures, portions of them may have to be removed with resulting cosmetic or functional deformities. Furthermore, repair of the resulting defect may involve some of these structures. The doctor will discuss this with regards to the particular location of your tumor prior to surgery.
  • The wound may become infected. A small number of surgical wounds (less than 5%) may become infected and require antibiotic treatment. If you are a particular risk for infection, you may be given an antibiotic prior to surgery.
  • There may be excessive bleeding from the wound. Such bleeding can usually be controlled during surgery. There may also be bleeding after surgery. There is very rarely a significant amount of blood loss but bleeding into a sutured graft or flap may inhibit good wound healing.
  • There may be an adverse reaction to medications used. We will carefully screen you for any history of past problems with medications; however, new reactions to medications may occur.
  • There is a small chance that your tumor may regrow after surgery (1-3%.) Previously treated tumors and large, longstanding tumors have the greatest chance for recurrence.


Please read the handouts you have been given. We want you to be as comfortable, relaxed and informed as possible.


  • DO advise us as soon as possible if you must cancel or change your appointment.
  • DO get a good night's sleep prior to surgery.
  • DO take your usual medications on schedule unless instructed otherwise by the doctor.
  • DO take any new medications the doctor prescribes for you.
  • DO eat breakfast.
  • DO bring someone with you to drive home.
  • DO ask any questions you might have.
  • Unless prescribed by one of your physicians, DO NOT TAKE ASPIRIN OR ANY ASPIRIN-CONTAINING PRODUCTS FOR TWO WEEKS PRIOR TO THE SURGERY. Please read the label on all over-the-counter medicines.
  • DO NOT consume alcohol 24 hours prior to or 48 hours after surgery.
  • DO NOT engage in strenuous physical activity 24 hours prior to surgery. Discuss with the doctor when you may resume strenuous physical activities.