Mohs Surgery

Mohs Surgery

What is Mohs surgery?

Mohs surgery, named after the inventor Frederic Mohs, is a microscopy-controlled surgical technique to remove skin cancers. It is most often used for Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC).

Mohs surgery is a method for removing skin cancers that have the highest cure rates (95%-99%) and saves the most normal skin. Normally, skin cancer is removed with a “safety margin” to remove the roots that extend beyond what can be seen with the naked eye. Utilizing the Mohs technique, a minimal margin of extra skin can be taken because 100% of the edges are checked in a complete way right in the office while you wait (approximately 45 minutes to 1 hour). In the event your skin cancer reached the edge of what is initially removed, your physician will return to the area where the skin cancer is present and remove a little more tissue. That area is then checked while you wait, and so on. This is done in small layers to assure that the least possible skin is removed.

The area will be numbed using an injection technique with lidocaine so that you will not have significant discomfort during the procedure. Re-administration of numbing medicine may be needed before each stage of cancer removal and also before repairing the wound. If you have a history of sensitivity to local anesthetics, please let us know.

Once the cancer has been removed, the decision about the best method of repair is made. Most commonly, the area is repaired in the office on the day of the surgery. The skin may be repaired with a simple row of stitches, a local flap (moving adjacent skin), or a skin graft (taking pieces of skin from somewhere else). Occasionally, it is deemed best to leave the wound open and let the area simply heal. Rarely, the skills of another specialist are required. If your physician anticipates that the repair may require the skills of another specialist, the repair of the wound is usually arranged later the same day or on a day shortly after that.

What are the benefits of Mohs surgery?

Instead of excising the tissue and sending it to an outside laboratory where it may take several days to receive a result, the skin cancer is examined by the Mohs surgeon under the microscope right away to ensure that the entire tumor is removed. Because of that, a smaller margin of healthy skin can be taken and thus a smaller wound and consequently a smaller scar results.

How long will I be at the office?

Mohs surgery will take more than one hour and may take half of a day, rarely more than that. Depending on how many “roots” the cancer has grown under the skin, several excision stages may be needed, each stage requiring 45-60 minutes for the laboratory to process.

How big will my scar be?

Skin cancer destroys normal tissue and removing the cancer by any method will result in a scar, even if the wound is sutured together with optimal technique and materials. The goal is a thin, linear scar that is hidden in a fold or wrinkle. Sometimes the wound cannot be sutured side-by-side and will require a flap from adjacent tissue or even a skin graft. Even then, the cosmetic outcome can be very good.


  • Please be sure that you know the exact location of the skin cancer. If you do not know the precise biopsy site, please call the office immediately so we can arrange for the site to be identified.
  • If you smoke, this may be the best time to quit. Ask you primary care provider what support is available to you. Smoking will significantly interfere with your healing.
  • If your Mohs surgery is on the lips and your dentist routinely gives you antibiotics prior to your appointment, please call our office so we can discuss pre-operative antibiotics for you.
  • If you take medically prescribed anticoagulants (Coumadin, Plavix, etc.), then you should continue them during and after surgery. If you are taking Coumadin (warfarin), you should have your INR checked within a week before surgery. Please have the results sent to our office before the surgery. Ideally, we would like the INR to be between 2.0 and 3.0 on the day of surgery.

Preoperative checklist:

  • You know the exact location of the skin cancer.
  • Please wear an older (not your favorite!) shirt that buttons down instead of a sweater that pulls over your head. Bring a jacket for staying warm.
  • Take all your regular medications, eat a good breakfast, and bring two or three snacks.
  • Bring a book, a tablet, or a friend to make the waiting time more enjoyable.
  • If you have questions before your surgery, please call the office at 781-762-5858.


  • You will have steri-strips taped directly over the wound and a gauze dressing over the steri-strips for two days. After that, you can remove the gauze dressing and cover the strips with a band-aid. The strips are designed to stay on for two weeks without being changed. You will need to keep them dry! After two weeks, we will remove both the strips and the sutures at our office.
  • Some patients will need to take antibiotics or prescription pain medication. Most patients just take extra-strength Tylenol.
  • If you had surgery on the forehead or near the eyes, there will be considerable swelling and bruising around your eyes 1-2 days after surgery.
  • You should take extra-strength Tylenol after surgery. The most pain occurs the first evening, and it is often helpful to take Tylenol-PM that first night to help you sleep. It is uncommon that patients require prescribed narcotics following Mohs surgery. In some cases, we will prescribe a stronger pain medication for use during the first couple of days after surgery.
  • You should avoid strenuous exercise, heavy lifting, bending or straining for seven days following the surgery. Avoid any activities that may cause tension on the wound until the sutures have been removed. Exercising immediately after surgery may cause additional bleeding and may cause the wound to open. Please do not resume any aquatic sports activities until the wound has healed.