Mohs Surgery Overview

When skin cancer is present, Mohs surgery is the ideal solution. The goal of this procedure is to remove as much of the skin cancer as possible while doing minimal damage to surrounding healthy tissue. Mohs surgery is usually done on an outpatient basis using a local anesthetic, meaning you’ll be able to return to your normal routine with minimal downtime and an excitingly brief recovery period.
Mohs surgery is an improvement to standard surgery (local excision), which involves removing visible cancer and a small margin of surrounding healthy tissue all at once. Mohs surgery allows your surgeon to verify that all cancer cells have been removed at the time of surgery. This increases the chance of a cure and reduces the need for additional treatments or additional surgery. To learn more about what this procedure can do for you, take a look at our locations page and reach out to the Certified Dermatology location that’s most convenient for you.

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Why Mohs Surgery?

Mohs surgery is used to treat the most common skin cancers, basal cell carcinoma, and squamous cell carcinoma, as well as some kinds of melanoma and other more unusual skin cancers.

Mohs surgery is especially useful for skin cancers that:

  • Have a high risk of recurrence or that have recurred after previous treatment
  • Are located in areas where you want to preserve as much healthy tissue as possible, such as around the eyes, ears, nose, mouth, hands, feet, and genitals
  • Have borders that are hard to define
  • Are large or aggressive

Potential Risks

As with any surgical procedure, Mohs surgery carries the following risks:

  • Bleeding
  • Pain or tenderness around the surgical site
  • Infection
  • Temporary or permanent numbness surrounding the surgical area, if small nerve endings are cut
  • Temporary or permanent weakness of the surgical area, if the tumor is large and a muscle nerve is severed
  • Itching or shooting pain in the affected area
  • An enlarged scar (keloid)

Preparing for Your Surgery

Mohs surgery can be technically challenging, and the board-certified dermatologists at Certified Dermatology can perform Mohs surgery thanks to their extensive training. Some Mohs surgeons have undergone specialized training — called a fellowship — to learn more about the procedure and become more proficient in Mohs surgery.

You may be asked to:

  • Stop taking certain medications. Let your surgeon know of any medications or supplements you’re taking, including any blood-thinning medications. Some supplements may affect your chances of bleeding after surgery, so make sure your surgeon knows about those, too. Continue taking any prescription medications as instructed unless your surgeon tells you otherwise.
  • Clear your schedule for the day. It’s not possible to predict how long Mohs surgery will take.
  • For most people, the procedure takes less than four hours. But your surgeon may advise you to plan as though surgery will take all day, since there’s a very small chance it could take that long.
  • Wear comfortable clothing. Wear casual clothes that are comfortable. Dress in layers so you can easily adapt if the room is warm or cold.
  • Bring something to help pass the time. Expect some waiting time during your Mohs surgery. Plan ahead by bringing a book, magazine, or other activity to help you pass the time.
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What You Can Expect

Mohs surgery is done on an outpatient basis in an operating room or procedure room with a nearby laboratory that allows the surgeon to examine the tissue after it’s removed. In most cases, the procedure lasts a few hours. Since it can be difficult to tell how extensive a skin tumor is just by looking at its surface, doctors often advise reserving the whole day for the procedure.

You likely won’t have to change into a surgical gown unless the location of the tumor requires it. To prepare you for surgery, your surgeon or a nurse cleanses the area to be operated on, outlines it with a special pen, and injects the area with a local anesthetic. The anesthetic numbs the skin so that you won’t feel any discomfort during the procedure. We’ll give you a clear idea of what to expect during your initial appointment.

During Your Procedure

Surgical Excision

Once the anesthetic has taken effect, your surgeon uses a scalpel to remove the visible portion of the cancer along with a thin, underlying layer of tissue that’s slightly larger than the visible tumor. A temporary bandage is placed on your incision. This takes only a few minutes. The surgeon then takes this tissue to the laboratory for analysis. This portion of the procedure typically takes the longest amount of time.

Laboratory Examination

You can expect to wait about an hour or so in a waiting room for the surgeon to return. It may help to bring a book or magazine to pass the time. You’ll be able to use the restroom or have a snack if you need to, but you won’t be able to leave the surgeon’s office until the procedure is complete. While you’re waiting, the surgeon or technician cuts the tissue sample into sections and examines them with a microscope. 

Complete Removal

Your surgeon takes great care to keep track of the exact spot where each piece of tissue was removed by making a map. That way, if a small area of cancer is found in one piece of tissue, the surgeon knows precisely where to continue with the surgery. If cancer remains, your Mohs surgery will continue. Your surgeon removes additional layers of tissue from the affected area until the last tissue sample removed is cancer-free.

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After Your Procedure

After all of the cancer has been removed, you and your surgeon can decide how to repair the wound. If the surgical area is extensive or complex, your surgeon may temporarily close your wound and then refer you to another surgeon for reconstructive surgery to repair the wound. Depending on the extent of the operation, this might include:

  • Letting the wound heal on its own (healing by second intention)
  • Using stitches to close the wound (primary closure)
  • Shifting skin from an adjacent area (skin flap) to cover the wound
  • Using a skin graft from another part of the body, such as behind the ear, to cover the wound

Your Exciting Results

One of the advantages of Mohs surgery is that you will be able to see your results right away, and you usually don’t leave your appointment until all of the skin cancer has been removed. You may have a follow-up visit with your surgeon or referring doctor to monitor your recovery to make sure your wound is healing properly.


What is Mohs surgery?

When is Mohs surgery recommended?

Can Mohs treat melanoma?

Who is the ideal candidate?

What is Mohs surgery?

Mohs surgery is used to treat skin cancer with a unique benefit. During surgery, the surgeon can see where the cancer stops. This isn’t possible with other types of treatment for skin cancer.

Mohs surgery is used to treat skin cancer with a unique benefit. During surgery, the surgeon can see where the cancer stops. This isn’t possible with other types of treatment for skin cancer.

When is Mohs surgery recommended?

Most Mohs patients have a common type of skin cancer, like basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). Mohs is also used to treat some rare skin cancers like DFSP, extramammary Paget’s disease, and Merkel cell carcinoma. Mohs is usually recommended when a BCC or SCC:

  • Is aggressive or large
  • Appears in an area with little tissue beneath it (e.g., eyelid, nose, ear, scalp, genitals, hand, or foot)
  • Was treated and has returned

Can Mohs treat melanoma?

Yes, dermatologists occasionally recommend Mohs for treating melanoma, the most serious type of skin cancer. Mohs is only used to treat early melanoma, and it must be a type of melanoma called lentigo malignant melanoma. This type of melanoma stays close to the surface of the skin for a while.

When treating melanoma, your surgeon will use a modified type of Mohs surgery called slow Mohs. It’s so-called because the patient must wait longer for the results. It’s not possible for the surgeon to look at the removed skin and know right away whether it contains cancer cells. More time is needed. If you have slow Mohs, your surgeon will remove the visible skin cancer and a bit of normal-looking skin around it. You’ll then be bandaged and sent home.

Most patients return the next day. Then, the patient learns whether more skin must be removed or the wound can be closed. Again, some wounds are left to heal on their own.

Who is the ideal candidate?

No matter what type of skin cancer you have, Mohs is only recommended for certain patients. You must have one skin cancer or a few skin cancers that are very close together. When you visit us for your informative initial appointment, we’ll be able to help you determine whether or not you’re the ideal candidate for Mohs surgery.

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