If you’ve been referred to us for Mohs surgery that means that your primary dermatologist has taken a sample of a suspicious skin lesion that turned out to be cancerous and needs further treatment to ensure removal. The most common cancers referred for Mohs surgery are basal cell carcinoma and squamous cell carcinoma.

Mohs surgery was developed by Dr. Frederic E. Mohs in the 1930s at the University of Wisconsin. This technique involves the methodical removal of thin layers of cancerous skin tissue, allowing for immediate microscopic examination to ensure complete removal of cancer cells while preserving normal, healthy skin. It has since evolved to become the gold-standard treatment for most types of skin cancer in high risk areas due to its exceptional cure rates and tissue preservation.

The Mohs surgery technique is as follows:

1. Preparation:

Before the surgery, Dr. Abdulhak will review your pathology report with you and answer any questions you may have. Next, he will identify the biopsy site using referral photos from your dermatologist. He will then mark out the biopsy site and a narrow margin around that area which will be removed during surgery. The site will be confirmed with you and photos will be taken for your chart.

**Some biopsy sites heal very well and to the naked eye, it may seem that no more cancer is present. However, skin cancers are like icebergs and the biopsy only removes what is “above the water”. In fact, multiple studies have shown that the rates of residual cancer presence after biopsy is almost 70%!

2. Numbing

The area will be cleansed with an antiseptic solution and a buffered local anesthetic will be injected to numb the area so that you won't feel any pain during the procedure. You may feel pressure or pulling sensations but nothing sharp.

3. Removal of First Layer

Once, you’re numb, Dr. Abdulhak carefully removes the cancer and a small margin of skin around and underneath it. The tissue layer comes out in the shape of small bowl or pie. Once the tissue is removed, a cautery device is used to control minor bleeding. and a bandage will then be placed. This step only takes a few minutes.

4. Lab Processing

While you wait, the removed tissue is taken to the lab, where it processed for microscopic evaluation. Dr. Abdulhak checks the tissue under the microscope to see if all the cancer is gone. If cancer is still present, another tissue layer is removed and the process is repeated. Some patients are clear after the first layer but some require 2 or more layers. Tissue processing can take up to 1 hour so please bring something to do while you wait (read a good book, have a snack, or listen to your favorite podcast)

5. Closure

Once the cancer is microscopically determined to be clear, Dr. Abdulhak will discuss options for wound closure, which may involve stitching the wound closed, letting it heal naturally, or using reconstructive techniques if necessary such as a flap or skin graft. All these options will be discussed with you in detail.

6. Recovery

After the surgery, you will receive instructions on how to care for the wound as it heals, including how to change the dressing, activities to avoid, timing of showers and any other information relevant to your closure technique.

The goal of the procedure is to effectively remove the skin cancer while preserving as much healthy tissue as possible and achieving the best possible functional and cosmetic outcome.

Alcalay J, Alkalay R. Histological evaluation of residual basal cell carcinoma after shave biopsy prior to Mohs micrographic surgery. J Eur Acad Dermatol Venereol. 2011 Jul;25(7):839-41. doi: 10.1111/j.1468-3083.2010.03881.x. Epub 2010 Nov 4. PMID: 21054570.

van Loo E, Mosterd K, Krekels GA, et al. Surgical excision versus Mohs' micrographic surgery for basal cell carcinoma of the face: A randomised clinical trial with 10 year follow-up. Eur J Cancer. 2014;50(17):3011-3020. doi:10.1016/j.ejca.2014.08.018

AAD/ACMS/ASDSA/ASMS 2012 appropriate use criteria for Mohs micrographic surgery: a report of the American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery Association, and the American Society for Mohs Surgery. Dermatol Surg. 2012;38(10):1582-1603. doi:10.1111/j.1524-4725.2012.02574.x

Tierney EP, Hanke CW. Cost effectiveness of Mohs micrographic surgery: review of the literature. J Drugs Dermatol. 2009;8(10):914-922.

Ravitskiy L, Brodland DG, Zitelli JA. Cost analysis: Mohs micrographic surgery. Dermatol Surg. 2012;38(4):585-594. doi:10.1111/j.1524-4725.2012.02341.x

van Lee CB, Roorda BM, Wakkee M, et al. Recurrence rates of cutaneous squamous cell carcinoma of the head and neck after Mohs micrographic surgery vs. standard excision: a retrospective cohort study. Br J Dermatol. 2019;181(2):338-343. doi:10.1111/bjd.17188

Bittner GC, Cerci FB, Kubo EM, Tolkachjov SN. Mohs micrographic surgery: a review of indications, technique, outcomes, and considerations. An Bras Dermatol. 2021;96(3):263-277. doi:10.1016/j.abd.2020.10.004

Below is a comprehensive video from the American College of Mohs Surgeons that reviews the process as well as a figure explaining the benefits of Mohs tissue processing in comparison to standard excisions: