Mohs Surgery

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What is Mohs surgery?

Mohs surgery is a procedure to treat cancerous lesions, growths and tumors of the skin. Mohs surgery can treat local skin cancers, including basal cell carcinoma, melanoma, and squamous cell carcinoma. Mohs surgery involves removing skin tissue one layer at a time and examining it under a microscope. This continues until the final tissue layer is free of cancerous cells. 

Mohs surgery is a highly effective treatment of skin cancer. It also limits the size of scars because it preserves healthy tissue. As a result, Mohs surgery is often useful for skin cancer on the face, ears or neck.

Mohs surgery is only one method used to treat skin cancer. Discuss all your treatment options with your doctor to understand which treatment is right for you. 

Other procedures that may be performed

Your doctor may perform other procedures in addition to Mohs surgery. These include:

  • Reconstructive surgery rebuilds and restores body or facial structures that cancer removal has disfigured.

  • Skin grafting is the surgical transplantation of skin and its underlying tissues from one area to another. Your doctor may use skin grafting to help close your wound or minimize scarring.

Why is Mohs surgery performed?

Your doctor may recommend Mohs surgery to treat cancerous skin conditions. Cancer occurs when old or damaged cells divide and multiply uncontrollably. Cancer cells rapidly reproduce even when your body signals them to stop. 

Mohs surgery can treat the following types of skin cancer: 

  • Basal cell carcinoma begins in the basal cells, which are the cells at the base of the epidermis (outermost layer of skin). This is the most common form of skin cancer and usually occurs on body areas that get sun exposure.

  • Squamous cell carcinoma begins in the squamous cells, which are the cells at the surface of the epidermis. This type of skin cancer is most common on body areas that get sun exposure. However, it can occur anywhere on the body.

  • Melanoma begins in the melanocytes (pigment-making skin cells). While melanoma is highly curable in its early stages, it can spread quickly and become deadly.

Your doctor may recommend Mohs surgery to treat your skin cancer if:

  • It has not spread to your lymph nodes or other areas.

  • It is located near scar tissue.

  • It is large or growing rapidly.

  • It is an aggressive type of skin cancer.

  • The edges are hard to define.

  • You are an organ transplant or lymphoma patient.

  • You have skin cancer on your face, neck or hand or other visible areas.

  • Your skin cancer has recurred after other treatments or is likely to recur.

Who performs Mohs surgery?

Dermatologists with advanced training in the procedure usually perform Mohs surgery. Dermatologists specialize in the medical and surgical care of the skin, hair and nails.

How is Mohs surgery performed?

Mohs surgery is performed as an outpatient procedure in a doctor’s office or clinic. The surgery can take from one hour to several hours depending on the size and type of your skin cancer. Mohs surgery generally includes these steps:

  1. You will dress in a patient gown or wear your own loose-fitting clothing.

  2. You will lie on a procedure table.

  3. Your doctor will clean the procedure area and inject a local anesthetic to numb it. You will be awake during the procedure but will not feel pain. You may also receive a sedative to keep you relaxed and comfortable during the procedure.

  4. Your doctor will remove the visible tumor along with a thin layer of surrounding tissue.

  5. Your team prepares the tissue layer, puts it on a slide, and examines it under a microscope.

  6. If cancer is present in the tissue, your doctor will take another layer of tissue and examine it. This continues until your doctor finds a cancer-free layer.

  7. Your team will bandage or dress the wound. Often, a plastic surgeon will close the wound, either in the same clinic or you may need to travel to another location. You may have reconstruction surgery the same day or another day to repair the area.

Will I feel pain?

Your comfort and relaxation is important to both you and your care team. You should not feel pain during your Mohs surgery with local anesthetic. Tell your doctor or a member of your healthcare team if you are uncomfortable.

What are the risks and potential complications of Mohs surgery?

Complications after Mohs surgery are not common, but any procedure involves risks and potential complications. Complications may become serious in some cases. Complications can develop during the procedure or recovery. Risks and potential complications of Mohs surgery include:

  • Anesthesia reaction, such as an allergic reaction

  • Bleeding

  • Infection

  • Numbness and nerve damage

  • Pain and tenderness

  • Poor wound healing

  • Scarring

Reducing your risk of complications

You can reduce the risk of certain complications by following your treatment plan and:

  • Following activity, dietary and lifestyle restrictions and recommendations before surgery and during recovery

  • Notifying your doctor immediately of any concerns, such as bleeding, fever, increase in pain, or wound redness, swelling or drainage

  • Not smoking as this can lead to poor wound healing

  • Taking your medications exactly as directed

  • Telling all members of your care team if you have any allergies

How do I prepare for my Mohs surgery?

You are an important member of your own healthcare team. The steps you take before your procedure can improve your comfort and outcome.  You can prepare for Mohs surgery by:

  • Answering all questions about your medical history, allergies, and medications. This includes prescriptions, over-the-counter drugs, herbal treatments, and vitamins. It is a good idea to carry a current list of your medical conditions, medications, and allergies at all times.

  • Stopping smoking as soon as possible. Even quitting for just a few days can be beneficial and help the healing process.

  • Taking or stopping medications exactly as directed. This may include not taking aspirin, ibuprofen (Advil, Motrin), and blood thinners.

Questions to ask your doctor

Preparing for Mohs surgery can be stressful. It is common for patients to forget some of their questions during a doctor’s office visit. Contact your doctor with concerns and questions before surgery and between appointments. 

It is also a good idea to bring a list of questions to your appointments. Questions can include:

  • Why do I need Mohs surgery? Are there any other options for treating my condition?

  • Will Mohs surgery cure my skin cancer?

  • How much scarring will I have after the procedure?

  • How long will the procedure take? When can I go home?

  • What restrictions will I have after the procedure? When can I return to work and other activities?

  • What assistance will I need at home?

  • How should I take my medications?

  • How will you treat my pain?

  • When should I follow up with you?

  • How should I contact you? Ask for numbers to call during and after regular hours.

What can I expect after my Mohs surgery?

Knowing what to expect after Mohs surgery can help you get back to your everyday life as soon as possible. 

How will I feel after Mohs surgery?

You may have swelling, bruising, and minor pain after Mohs surgery. Your doctor may recommend applying ice packs to help with swelling and bruising. Pain after Mohs surgery usually responds to over-the-counter pain medicines. Take them as your doctor recommends.

When can I go home?

You should be able to go home right after your Mohs surgery. Your doctor may recommend avoiding strenuous activity or exercise for up to seven days in order for your wound to heal. You may need to return to your doctor to get your stitches out after seven to 10 days. Wound scars will continue to heal over the coming months. Talk with your doctor about any scars that are not healing as expected.

When should I call my doctor?

It is important to keep your follow-up appointments after Mohs surgery. Contact your doctor for questions and concerns between appointments. Call your doctor right away or seek immediate medical care if you have:

  • Bleeding

  • Fever

  • Pain that is not controlled by your pain medication

  • Unexpected drainage, pus, redness or swelling of your incision

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Nov 17
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  2. Overview of Mohs Micrographic Surgery. American College of Mohs Surgery.
  3. The Mohs Procedure. American College of Mohs Surgery.
  4. Why Does My Cancer Need Mohs Surgery. American College of Mohs Surgery.
  5. Reconstructive and Post-Operative Care. American College of Mohs Surgery.
  6. Mohs Surgery Facts. American College of Mohs Surgery.
  7. What Is a Mohs Surgeon. American College of Dermatology.
  8. Skin Cancer: Diagnosis, Treatment, and Outcome. American Academy of Dermatology.
  9. Complications of Mohs Surgery. Lahey Hospital and Medical Center.