What Is Mohs Surgery? The Complete Patient Guide

What Is Mohs Surgery?

If you have been diagnosed with basal cell carcinoma (BCC) or squamous cell carcinoma (SCC), your dermatologist may have recommended Mohs micrographic surgery. The name might sound unfamiliar, and the idea of surgery can feel overwhelming. That is completely understandable. This guide is designed to walk you through every aspect of the procedure so that you can approach your treatment with confidence and clarity.

Mohs surgery is a highly specialized surgical technique used to treat skin cancer. It was developed by Dr. Frederic Mohs in the 1930s and has been refined over decades into the most precise and effective method for removing certain types of skin cancer. Unlike standard excision, where a surgeon removes the visible tumor along with a margin of surrounding tissue and sends it to a lab, Mohs surgery involves removing skin cancer layer by layer and examining each layer under a microscope in real time. This means that 100 percent of the surgical margin is evaluated during the procedure itself, ensuring complete cancer removal while sparing as much healthy tissue as possible.

How Does Mohs Surgery Work? The Layer-by-Layer Process

The procedure follows a carefully structured process that sets it apart from all other skin cancer treatments.

Step 1: Preparation and Local Anesthesia. On the day of your surgery, the area around your skin cancer is cleaned and numbed with local anesthesia. You will be awake throughout the procedure, which is performed on an outpatient basis. There is no need for general anesthesia in the vast majority of cases.

Step 2: Removal of the First Layer. Dr. Kaplan carefully removes a thin layer of tissue that includes the visible tumor. The tissue is color-coded and mapped so that its exact position on your body is recorded.

Step 3: Microscopic Examination. While you wait comfortably, the removed tissue is processed and examined under a microscope. This is the key step that makes Mohs surgery unique. Unlike standard pathology where only small sections of the margin are sampled, Mohs examines 100 percent of the tissue edges. This thorough analysis is what gives the procedure its exceptional cure rate.

Step 4: Additional Layers if Needed. If cancer cells are found at any edge of the removed tissue, Dr. Kaplan knows exactly where they are located thanks to the mapping system. Only that specific area is targeted for the next layer, preserving healthy tissue everywhere else. This process repeats until no cancer cells remain.

Step 5: Reconstruction. Once the site is completely cancer-free, the wound is repaired. Depending on the size and location, this might involve direct closure with stitches, a local skin flap, or a skin graft. Dr. Kaplan plans the reconstruction with both complete cancer removal and the best possible cosmetic outcome in mind.

Why Does Mohs Surgery Have a 99% Cure Rate?

The cure rate for Mohs surgery is approximately 99 percent for basal cell carcinoma and 97 percent for squamous cell carcinoma. These numbers are significantly higher than those for standard surgical excision, which typically achieves cure rates of around 93 to 95 percent.

The reason is straightforward. Standard excision relies on sampling small sections of the tissue margin, which means that some cancer cells can be missed. Mohs surgery examines the entire margin, leaving virtually no room for residual cancer. If cancer cells remain, they are detected immediately and removed in the next layer. You can learn more about the science behind these outcomes in our article on why Mohs surgery achieves a 99 percent cure rate.

Who Needs Mohs Surgery?

Mohs surgery is not necessary for every skin cancer. It is specifically recommended in situations where precision and tissue preservation are most important.

Skin cancers in cosmetically sensitive areas such as the nose, eyelids, ears, lips, and around the eyes are ideal candidates for Mohs. These areas have limited tissue, and removing too much can affect both appearance and function. Learn more about Mohs on the face in our guide to eyelid, ear, and lip procedures.

Recurrent skin cancers that have come back after previous treatment benefit from Mohs because recurrent tumors often have irregular borders that are difficult to assess with standard excision.

Large or aggressive tumors with poorly defined borders require the precision of layer-by-layer examination to ensure complete removal.

Tumors in areas where tissue conservation matters, such as the fingers, genitals, and shins, are well-suited for Mohs because the technique minimizes the size of the wound.

Mohs surgery is used to treat basal cell carcinoma and squamous cell carcinoma, the two most common forms of skin cancer.

What to Expect on the Day of Surgery

Mohs surgery is performed as an outpatient procedure, which means you will go home the same day. However, the process can take several hours because of the laboratory analysis performed between each layer.

Arrival and Preparation. Plan to arrive at the hospital on time with comfortable clothing that does not need to be pulled over your head if the surgery is on your face or neck. Dr. Kaplan performs Mohs surgery at Assuta Hospital and Herzliya Medical Center (HMC). Patients insured with Maccabi can be treated at Assuta, while Clalit patients can be treated at HMC.

During the Procedure. After the first layer is removed, you will wait while the tissue is processed and examined. This typically takes 30 to 45 minutes per layer. Most tumors require one to three layers, but some may require more. Bring a book, a phone charger, or something to help pass the time. For more detailed preparation tips, see our article on how to prepare for Mohs surgery.

After the Procedure. Once the cancer is fully removed and the wound is repaired, you will receive detailed wound care instructions. Most patients experience mild discomfort that can be managed with over-the-counter pain medication. A pressure bandage is typically applied and should remain in place for 24 to 48 hours.

Where Is Mohs Surgery Performed?

Dr. Yehonatan Kaplan performs Mohs micrographic surgery at two leading hospitals in Israel. Assuta Hospital is available for patients covered by Maccabi health insurance, while Herzliya Medical Center serves patients with Clalit coverage. Both facilities are equipped with the on-site laboratory capabilities that Mohs surgery requires, and both provide a comfortable, professional environment for the procedure.

Is Mohs Surgery Painful?

One of the most common concerns patients have is whether the procedure will be painful. The honest answer is that Mohs surgery is very well-tolerated. Local anesthesia numbs the treatment area completely, so you should not feel pain during the tissue removal. You may feel some pressure or tugging, but this is generally not uncomfortable. If at any point you experience discomfort, additional anesthesia can be administered immediately.

After the anesthesia wears off, most patients describe the sensation as mild soreness or a dull ache. Over-the-counter pain relievers such as paracetamol are usually sufficient. Your recovery experience will depend on the size and location of the surgery, and our week-by-week recovery timeline can help you understand what to expect at each stage.

Taking the Next Step

Being diagnosed with skin cancer is stressful, but understanding your treatment options can make a significant difference in how you feel going into surgery. Mohs surgery offers the highest cure rate available, the greatest preservation of healthy tissue, and the best cosmetic outcomes for skin cancers in sensitive areas.

If you have been recommended for Mohs surgery and have questions, consider reviewing our list of 10 questions to ask your dermatologist before Mohs surgery. Being informed and prepared is one of the most empowering things you can do for your own health.