Surgical Services

Mohs Skin Cancer Surgery

Skin cancer is serious. The three most common skin cancers that make up almost 99 percent of all skin cancers include basal cell carcinoma, squamous cell carcinoma and melanoma. Basal cell carcinoma is the most common cancer in the United States. Although melanoma makes up only 4 percent of skin cancers, it causes about 75 percent of skin cancer deaths.

If you’ve had a blistering sunburn at any point in your life, your chances for skin cancer, including melanoma, increases dramatically.

There are a variety of treatment options for these skin cancers including topical medications, electrodessication and cautery (also known as scrape and burn), photodynamic therapy (PDT), cryotherapy, standard excision, radiation, systemic medications and Mohs surgery, a specialty at Greenbrae Dermatology. The skin cancer experts at Greenbrae Dermatology can help determine which treatment option is best for you.

What is Mohs surgery?

Mohs surgery is the surgical removal of skin cancer from your skin. It is the only treatment method that allows for complete evaluation of the margins (areas surrounding the visible skin cancer) while you wait in the medical office.

This way, the least amount of healthy tissue is removed. This is especially important when skin cancer develops in a sensitive area where it is important to preserve as much healthy tissue as possible, such as around the eyes, nose, or lips. Most Mohs surgeons are board-certified dermatologists who have completed extensive training in Mohs surgery. Mohs surgeons not only perform the surgery, but also examine the removed tissue under the microscope to ensure all cancer cells have been removed. Most Mohs surgeons also have training in reconstructive techniques to help your skin heal as fast as possible and minimize scarring. Your dermatologist will determine if Mohs surgery is appropriate for treating your skin cancer. This depends on the type of skin cancer you have, its size, and its location on your body.

Why Mohs surgery?

Mohs surgery is now the standard of care for certain skin cancers on the head and neck. It is a precise technique that provides the highest cure rate out of any current treatment option while sparing as much healthy tissue as possible. Our Mohs surgeons have the ability to process the excised skin, evaluate the skin cancer under the microscope and examine 100% of the margins to ensure complete removal of the skin cancer.

How is Mohs surgery performed?

Mohs surgery is usually performed as an outpatient procedure in a dermatologist’s office. You remain awake during Mohs surgery and receive a local anesthetic to numb the surgical area. The use of a local anesthetic instead of general anesthesia (which puts the patient to sleep) is much safer. It also reduces recovery time with fewer side effects.

If you are concerned about discomfort during the procedure, let your Mohs surgeon know. He or she can make you feel more comfortable. Once the area around the skin cancer has been numbed, your Mohs surgeon removes the visible skin cancer and a thin layer of surrounding skin. Then, your skin is bandaged so that you can wait comfortably. While you wait, the removed tissue is examined under a microscope by the Mohs surgeon to determine if there are any cancer cells remaining at the edges of the removed tissue.

If cancer cells are still present at any edge of the removed tissue, your Mohs surgeon will remove another thin layer of skin and examine it under a microscope. This process is repeated until all cancer cells have been removed.

After the Mohs surgery is completed, your Mohs surgeon will discuss with you the best way for the wound to heal. You may need stitches,
or your wound may be bandaged and allowed to heal on its own. Any surgical repair is usually performed on the same day. Your Mohs surgeon will determine the best approach with you. Sometimes, you may be referred to another medical doctor to repair the wound.

What happens during Mohs surgery?

  1. The visible tumor and a thin layer of surrounding skin are removed.
  2. The tissue is examined under a microscope to see if any cancer cells remain at any of the edges.
  3. If any cancer cells remain, additional skin is removed and examined under the microscope.
  4. This process continues until no more cancer cells are found at the edges.

When should you have Mohs surgery?

Mohs surgery is an excellent choice for the treatment of most primary skin cancers. When the skin cancer:

  • Develops on areas where cosmetic appearance and function are important
  • Has recurred after previous treatments
  • Is large
  • Has edges that are ill defined
  • Grows rapidly

What should you know about the day of your surgery

  • Surgery is performed under local anesthesia and there is no general anesthesia
  • It may be good to bring a friend or family member for support. If you are having surgery around the eye or nose, you may need to bring someone as a driver since the post-operative bandage may obstruct your view.
  • Since Mohs ensure that 100% of the margins are clear of skin cancer, the procedure time can be unpredictable. Therefore, please plan for the appointment to take half of the day. However, on average, the procedure often takes between 3-4 hours.

Get In Touch


501 Sir Francis Drake Blvd., Suite 200
Greenbrae, California 94904

Phone number:

(415) 925-0550



Open Hours:

Monday – Friday: 8am – 5pm PST
Saturday: 8am – 4pm PST
Sunday: CLOSED

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