Mohs Surgery

What this procedure is

Mohs (pronounced "moze") surgery is a specialized way to treat skin cancer. During the procedure, a surgeon removes thin layers of skin one at a time. After each layer is removed, the surgeon looks at the tissue under a microscope in a nearby lab to check for cancer cells.

This process is repeated until no more cancer cells are found. By checking the tissue as they go, the surgeon can be very precise. The goal is to remove all of the skin cancer while keeping as much healthy skin as possible.

Because the surgeon acts as both the doctor performing the surgery and the pathologist (a doctor who studies tissues), they can see exactly where the cancer stops. This "micrographic" approach helps ensure the entire tumor is removed during a single visit.

What it treats or fixes

Mohs surgery is most often used to treat the two most common types of skin cancer:

• Basal cell carcinoma: A slow-growing cancer that starts in the top layer of skin.
• Squamous cell carcinoma: A cancer that may grow more deeply or spread if not treated.

Your clinician may recommend this procedure if the cancer is in a sensitive area where it is important to save as much healthy tissue as possible. This includes the face, nose, ears, eyelids, lips, or hands. It is also used for cancers that are large, have unclear edges, or have come back after a previous treatment.

In some cases, Mohs surgery may be used for other types of skin cancer, such as certain early-stage melanomas. Your medical team will determine if this is the right approach for your specific diagnosis.

How common it is & where it's done

Mohs surgery is a very common and well-established procedure. It is considered a standard treatment for many skin cancers because it has a high success rate. Thousands of these procedures are performed every year across North America.

This is typically an outpatient procedure, which means you do not need to stay in a hospital overnight. It is usually performed in a specialized medical office or a surgical suite that has its own laboratory. This allows the surgeon to process and examine the skin layers immediately while you wait.

The procedure is performed by a Mohs surgeon. These are often dermatologists who have completed extra fellowship training to master the surgical, laboratory, and microscopic skills needed for this specific technique.

Recovery: What to Expect

After your procedure, you will likely go home the same day. It is common to have some mild swelling, bruising, or tenderness around the surgical site. Your clinician may suggest over-the-counter pain relief or cold compresses to help you feel more comfortable during the first few days.

You will receive specific instructions on how to care for your wound. This usually involves keeping the area clean and dry for the first 24 to 48 hours. You may need to limit heavy lifting or intense exercise for a short time to allow the skin to heal without being pulled or stressed.

While healing is usually smooth, you should contact your care team if you notice:

• Bleeding that does not stop after applying firm pressure for 15 minutes.
• Increased pain, redness, or warmth around the site.
• A fever or unusual drainage from the wound.

Risks & Possible Complications

Like any surgery, Mohs surgery carries some risks. The most common side effects are temporary bruising and swelling. Some patients may experience minor bleeding or a small amount of discomfort as the numbing medicine wears off.

Other possible complications include:

• Infection: This is uncommon, but your clinician will provide steps to keep the area clean to prevent it.
• Nerve changes: If the tumor is near a nerve, you might feel temporary numbness or tingling. In rare cases, this can be permanent if a nerve is damaged during the removal of the cancer.
• Scarring: A scar will form at the site. However, Mohs surgery is designed to keep the scar as small as possible by removing only the cancerous tissue and sparing healthy skin.

Outcomes & Long-Term Results

Mohs surgery is known for having a very high success rate, often cited as up to 99% for the most common types of skin cancer. Because the surgeon checks the tissue edges during the procedure, it offers the highest chance of removing all the cancer while saving as much healthy skin as possible.

Once the area has healed, your clinician will schedule follow-up visits. These check-ups are important to ensure the site is healing well and to look for any new skin changes. Most people can return to their normal activities quickly, but long-term skin health depends on protecting yourself from the sun with hats, clothing, and sunscreen to prevent new cancers from forming.

Emotional Support & Reassurance

It is completely normal to feel a bit nervous about having surgery, especially on visible areas like the face. Remember that Mohs surgery is a very precise technique. Your surgical team is trained to focus on both removing the cancer and achieving the best possible cosmetic result for your recovery.

If you feel anxious, do not hesitate to ask your clinician questions about the process. Knowing what to expect can help you feel more in control. Many patients find comfort in knowing that this procedure is a standard, highly effective treatment that allows for immediate confirmation that the cancer is gone before they even leave the office.

Why doctors recommend it

Clinicians often recommend Mohs surgery for common types of skin cancer, such as basal cell carcinoma and squamous cell carcinoma. It is especially useful for cancers that are located in visible or sensitive areas where saving healthy skin is a priority. This includes the face, ears, nose, scalp, fingers, and toes.

Your doctor may also suggest this method if the skin cancer:

• Has returned after a previous treatment.
• Is large or growing rapidly.
• Has edges that are hard to see or define.
• Is located in an area with a high risk of the cancer coming back.

Urgent vs planned treatment

Mohs surgery is typically a planned, outpatient procedure. While skin cancer is a serious condition, it is rarely a medical emergency that requires immediate surgery on the same day it is found. Instead, your care team will work with you to schedule the procedure at a time that allows for proper preparation.

Even though it is planned, clinicians generally advise against long delays. Treating the area promptly helps prevent the cancer from growing larger or spreading into deeper layers of tissue. Your clinician will determine the best timeline based on the type of cancer and how quickly it appears to be changing.

Goals of treatment

The primary goal of Mohs surgery is to remove the skin cancer entirely while leaving as much healthy tissue behind as possible. This is known as a "tissue-sparing" technique. Because the surgeon examines the edges of the tissue under a microscope during the procedure, they can be more precise than with standard surgery.

Other important goals include:

• High success rates: This method is known for having a very high cure rate for many common skin cancers.
• Smaller scars: By removing only the cancerous cells, the surgeon can often keep the resulting wound as small as possible, which may lead to better healing and a less noticeable scar.
• Clear results: In most cases, the surgeon can confirm that all the cancer is gone before you leave the office.

Who may benefit

Mohs surgery is often recommended for the most common types of skin cancer, such as basal cell carcinoma and squamous cell carcinoma. It is especially helpful for cancers located on the face, ears, nose, lips, or hands. These are areas where it is important to save as much healthy skin as possible for both appearance and function.

Your clinician may suggest this procedure if your skin cancer is large, growing quickly, or has come back after a previous treatment. It is also a common choice for cancers that have "ill-defined" edges, meaning the borders are hard to see with the naked eye. Because the surgeon checks the tissue edges under a microscope during the procedure, it offers a very high cure rate while keeping the wound as small as possible.

When it may not be the right option

While Mohs surgery is highly effective, it is not always the first choice for every patient. For small, low-risk skin cancers on parts of the body with plenty of extra skin—like the back, chest, or legs—a standard excision (cutting out the tumor and stitching it up) may be faster and just as effective.

Because Mohs surgery is done in stages, it can sometimes take several hours or even most of the day. If a patient has health conditions that make it difficult to sit or lie still for a long time, your care team might discuss other options. Additionally, if the cancer has already spread to other parts of the body, different treatments like radiation or medication may be needed instead of or alongside surgery.

Questions to ask your care team

Choosing a treatment is a shared decision between you and your doctor. You may want to bring a list of questions to your appointment to help you feel more prepared. Here are a few smart questions to consider:

• Why is Mohs surgery the best option for my specific type of skin cancer?
• How long should I expect to be at the clinic on the day of the procedure?
• What are the chances of the cancer coming back after this surgery?
• How will the wound be repaired once the cancer is removed?
• What should I do to prepare my skin or manage my medications before the surgery?

In the procedure room

When you arrive for your procedure, you will be settled into a specialized treatment room. Your care team will help you get into a comfortable position, usually sitting or lying down on a surgical table. The area of skin being treated will be cleaned thoroughly with a special soap to help prevent infection.

Depending on where the skin cancer is located, you may be asked to change into a surgical gown, or you may be able to stay in your own comfortable clothing. The team will ensure you have everything you need to remain relaxed during the process.

High-level steps

The Mohs procedure happens in stages. First, your clinician removes the visible part of the skin cancer along with a very thin layer of tissue beneath it. This tissue is then mapped and taken to an on-site lab to be processed and examined under a microscope. While the lab work is being done, a temporary bandage is placed on your skin, and you will wait in a comfortable area.

If the lab shows that cancer cells are still present at the edges, the surgeon will return to remove another thin layer of tissue. They only remove tissue from the specific spot where the cancer was found, which helps save as much healthy skin as possible. This process repeats until the lab confirms that the edges (margins) are completely clear of cancer.

Anesthesia and pain control

Mohs surgery is typically performed using local anesthesia. This means a numbing medicine is injected directly into the skin around the surgical site. You will remain awake and alert throughout the day, but the area being worked on will be numb.

While you may feel some pressure, tugging, or movement during the procedure, you should not feel pain. If you begin to feel any discomfort as the numbing medicine wears off between stages, your clinician may provide additional injections to keep you comfortable. Most patients find the process very manageable with this approach.

Monitoring and safety steps

Your safety is a priority throughout the day. Your care team may monitor your vital signs, such as your blood pressure or pulse, to ensure you are reacting well to the anesthesia. The surgical area is kept sterile (completely clean and free of germs) to reduce the risk of infection.

Because you are awake, you can communicate with your team at any time. They will check in with you frequently to make sure you are comfortable and to see if you need a break, a snack, or a drink while you wait for lab results.

Immediately after the procedure

Once the lab confirms that all the cancer has been removed, your clinician will discuss the best way to help the area heal. There are several options depending on the size and location of the wound:

• The wound may be closed with stitches.
• A skin graft (moving skin from another part of the body) or a skin flap (shifting nearby skin) may be used to cover the area.
• In some cases, the wound may be left to heal naturally on its own.

A protective bandage will be applied to the site. You will receive clear instructions on how to care for the wound at home, what activities to avoid, and when to return for a follow-up visit or to have stitches removed.

Typical procedure length

It is difficult to predict exactly how long your visit will last because the surgeon cannot know how many layers will be needed until they look at the tissue under the microscope. Most procedures take several hours, but some may take a full day. It is helpful to clear your schedule for the entire day to avoid feeling rushed.

A large portion of this time is spent waiting for the lab to process the tissue samples. You may want to bring a book, a tablet, or another quiet activity to help pass the time between the surgical stages.

Common approaches (open vs minimally invasive)

Mohs surgery is a specialized, tissue-sparing technique used to treat skin cancer. Unlike standard surgeries that cut out a large area of skin all at once, Mohs is done in stages. The surgeon removes the visible cancer and a very thin layer of tissue, then checks it under a microscope while you wait. This allows them to save as much healthy skin as possible, making it a minimally invasive option compared to wide excisions.

The procedure is usually performed under local anesthesia, meaning the area is numbed but you remain awake. Because it preserves healthy tissue, it is often chosen for sensitive areas like the face, nose, ears, or hands. Once the cancer is fully removed, your clinician will decide how to handle the wound. They may close it with stitches, use a skin graft, or in some cases, leave the wound open to heal on its own.

Partial vs total

The goal of Mohs surgery is always the total removal of the skin cancer. The term "partial" does not typically apply to the removal of the tumor itself, as leaving cancer cells behind increases the risk of it growing back. The surgeon continues the process layer by layer until the margins are completely clear of cancer cells.

However, the procedure is distinct from "total" wide excision where a large safety margin of healthy skin is removed automatically. In Mohs surgery, the surgeon only removes tissue where cancer is detected. This precise approach ensures that the total cancer is removed without taking unnecessary amounts of the surrounding healthy skin.

Revision or repeat procedures

Mohs surgery has a very high success rate, but it is also a common choice for treating skin cancers that have come back (recurred) after previous treatments. Because it checks 100% of the margins, it is often used to correct or "revise" areas where other methods did not fully remove the cancer.

In rare cases where skin cancer returns after Mohs surgery, the procedure can be repeated. Your clinician may also recommend additional or alternative treatments, such as radiation therapy, depending on the type of cancer and where it is located.

Tests and imaging that may be done

Because Mohs surgery treats skin cancer that is visible on the surface, extensive imaging tests like X-rays or CT scans are rarely needed. Instead, your care team will focus on reviewing your medical history and examining the skin.

The most common step before surgery is a biopsy. This is a procedure where a clinician removes a small sample of the skin to look at it under a microscope. This confirms the diagnosis of skin cancer before the Mohs procedure begins. On the day of surgery, the surgeon will examine the area again to mark the site.

Medication adjustments

It is important to give your surgical team a complete list of everything you take. This includes prescription medications, over-the-counter drugs, vitamins, and herbal supplements. Some substances can increase the risk of bleeding during and after surgery.

Your clinician will give you specific instructions on what to do with your current medications. Only stop taking medicines if your clinician specifically instructs you to do so.

• Blood thinners: If you take aspirin, warfarin, or other blood thinners, ask your doctor if you should continue them. In many cases, you will stay on these medications to prevent heart or stroke issues, but your surgeon needs to know in advance.
• Supplements: Your team may ask you to stop taking certain supplements, such as Vitamin E, fish oil, garlic, or ginkgo biloba, a few days before surgery.
• Alcohol and tobacco: You may be advised to avoid alcohol and smoking for a period before and after surgery, as these can slow down the healing process.

Day-before and day-of instructions

Mohs surgery is done in stages, and you will spend time waiting while the lab analyzes the tissue. Because of this, the appointment can last several hours or even the whole day. Being prepared can help make the day more comfortable.

Consider this checklist for the day of your surgery:

• Eat breakfast: Since Mohs surgery is usually done with local anesthesia (you are awake), you typically do not need to fast. Eat a normal breakfast unless your team tells you otherwise.
• Dress for comfort: Wear loose, comfortable clothing. If the surgery is on your face, wear a shirt that buttons down the front so you do not have to pull it over your head later.
• Bring entertainment: Bring a book, magazine, or tablet with headphones to help pass the time while you wait for lab results between stages.
• Plan your ride: Ask your clinic if you need someone to drive you home. This is often recommended if the surgery is near your eye or if you receive medication that helps you relax.

General surgical risks

Mohs surgery is widely considered a safe procedure, but like any surgery, it carries some general risks. Most side effects are minor and can be managed easily at home.

• Bleeding: It is common to see a small amount of bleeding or oozing from the wound after the surgery. In some cases, a collection of blood (hematoma) may form under the skin.
• Pain and tenderness: Once the local anesthesia wears off, the area may feel sore, tender, or tight.
• Infection: There is a small risk that germs may enter the wound, causing redness, warmth, or swelling.

Procedure-specific complications

Because Mohs surgery involves removing skin layers and repairing the area, specific complications can sometimes occur. These often depend on the size of the cancer and where it is located on your body.

• Nerve effects: If the cancer was near tiny nerves in the skin, you may feel temporary numbness, burning, or shooting pain. In rare cases, nerve damage can be permanent or cause muscle weakness.
• Scarring: All surgery leaves a scar. While surgeons try to minimize this, some scars may become raised, red, or thickened (keloids).
• Wound healing issues: Occasionally, the wound may open up after stitches are placed, or the skin used to repair the area may not heal as expected.
• Recurrence: Although Mohs surgery has a very high success rate, there is always a small chance that the skin cancer could come back.

How complications are treated

Most complications are treatable and improve with time. Your clinical team will provide detailed instructions to help your wound heal safely.

• Managing discomfort: Mild bleeding can usually be stopped with firm pressure. Pain is often managed with over-the-counter medicine or ice packs.
• Treating infection: If the wound shows signs of infection, your doctor may prescribe antibiotics to clear it up.
• Scar care: If a scar becomes itchy or raised, treatments like silicone sheets, injections, or minor revision procedures can help improve how it looks and feels.
• Monitoring: Regular follow-up visits allow your doctor to check your healing and watch for any signs of the cancer returning.

Pain control medicines

During your Mohs surgery, your clinician will use a local anesthetic. This is a numbing medicine injected directly into the skin so you do not feel pain during the procedure. You will remain awake, but the area being treated will feel numb. This medicine often includes a small amount of epinephrine, which helps reduce bleeding during the surgery.

After the surgery, most people have only mild discomfort. Your clinician may suggest over-the-counter pain relievers like acetaminophen. They might ask you to avoid certain medicines like ibuprofen or naproxen for a short time, as these can sometimes increase the risk of bleeding. Your care team will provide a specific plan for your recovery based on your health history.

Antibiotics

Antibiotics are medicines used to prevent or treat infections caused by bacteria. Most people having Mohs surgery do not need them. However, your clinician may prescribe them if the surgery involves a complex area or if you have certain health conditions, such as a heart valve issue or a recent joint replacement, that increase your risk of infection.

If an antibiotic is needed, it may be given as a pill to swallow or as an ointment applied directly to the wound. Your clinician will tailor this decision based on your medical history and the details of your procedure. If you have any known allergies to medicines, be sure to tell your surgical team before the day of your surgery.

Blood thinners and clot prevention

Blood thinners (anticoagulants) are medicines that help prevent dangerous blood clots. If you take these for a heart condition or to prevent a stroke, it is very important to talk to your clinician about them. In many cases, surgeons prefer that you continue taking your prescribed blood thinners to keep you safe from other health risks like heart attack or stroke.

While these medicines can make you more likely to bruise or have minor bleeding at the surgery site, your clinician is trained to manage this during the procedure. Never stop taking a prescribed blood thinner unless both your Mohs surgeon and the doctor who prescribed the medicine tell you to do so. They will work together to create a safe plan for your surgery.

Emergency warning signs

While serious complications from Mohs surgery are rare, uncontrolled bleeding requires immediate attention. Your care team will likely instruct you to apply firm, steady pressure over the bandage for 20 minutes if bleeding occurs. Do not lift the bandage to check during this time.

You should seek immediate medical help or go to the emergency room if:

• Bleeding soaks through the bandage and does not stop after 20 minutes of firm pressure.
• You feel faint, dizzy, or lightheaded.
• You experience sudden difficulty breathing or severe swelling near the airway (if surgery was on the neck).

Call your surgeon or clinic if…

Contact your surgical team if you notice signs that the wound is not healing properly. Catching an infection or wound issue early is important for your recovery.

• Signs of infection: The area becomes very red, feels hot to the touch, or the redness spreads outward from the wound.
• Drainage: You see thick yellow or green fluid (pus) coming from the wound, or it has a bad smell.
• Fever: You develop a fever or chills.
• Pain: Your pain gets worse after the first few days, or pain medicine does not provide relief.
• Stitches: The stitches come loose or the edges of the wound start to open up.

Expected vs concerning symptoms

It helps to know what is part of the normal healing process and what might be a complication.

Swelling and Bruising

• Expected: It is normal to have bruising and swelling, especially for surgery near the eyes or nose. This often peaks 2 to 3 days after surgery before getting better.
• Concerning: A sudden, rapidly growing lump under the skin that feels firm and painful (a collection of blood called a hematoma).

Sensations

• Expected: You may feel tightness, itching, or mild numbness around the scar as nerves heal.
• Concerning: New or spreading numbness, or loss of movement in the area that was not discussed as a potential side effect.

Non-surgical treatments

Your clinician may suggest options that do not involve cutting the skin. These are often used for very early-stage or surface-level skin cancers. Common choices include:

• Topical creams: Medicated creams applied to the skin to help the immune system attack the cancer cells or stop them from growing.
• Radiation therapy: Using high-energy beams to destroy cancer cells. This is often used for patients who cannot have surgery or if the cancer is in a difficult spot.
• Cryosurgery: Freezing the cancer cells with liquid nitrogen to destroy them.
• Curettage and electrodesiccation: A process where the clinician scrapes away the cancer and uses an electric needle to kill any remaining cells.

While these treatments can be effective for some, they do not allow the clinician to look at the edges of the tissue under a microscope during the procedure to ensure all the cancer is gone.

Watchful waiting

In some very specific cases, a clinician might suggest "watchful waiting." This means monitoring the spot closely rather than treating it right away. This is not a common approach for most skin cancers because they tend to grow and spread over time.

This approach is usually reserved for very slow-growing cancers in patients who have other major health issues or a limited life expectancy. The goal is to ensure the treatment itself does not cause more stress or harm than the slow-growing spot would. Your clinician will help you weigh the risks of the cancer versus the risks of the procedure.

When surgery becomes the best option

While non-surgical options exist, Mohs surgery is often the preferred choice for certain situations. Your clinician may recommend it if the cancer is in a "high-stakes" area like the face, nose, eyelids, or ears. In these spots, saving as much healthy skin as possible is vital for both how you look and how those parts of your body function.

Surgery may also become the best option if:

• The cancer is large or growing quickly.
• The edges of the cancer are not clearly defined.
• The cancer has come back after a previous treatment (recurrence).
• The cancer is an aggressive type that is likely to spread.

Because Mohs surgery allows the doctor to check 100% of the tissue edges during the procedure, it offers the highest cure rate. This precision helps ensure the cancer is fully removed while leaving the smallest possible scar.

Hospital services that commonly perform this surgery

Mohs surgery is most often performed in specialized dermatology departments or dedicated dermatologic surgery centers. These facilities are equipped with a specific laboratory where the surgeon can examine tissue samples immediately during your visit.

Many large medical centers and university hospitals offer this procedure through their skin cancer clinics. Because Mohs surgery is usually an outpatient procedure, it may take place in a hospital-based clinic or a private surgical suite rather than a traditional operating room.

Patient resources and support services

Most hospitals provide resources to help you prepare for the day of surgery. This often includes a pre-operative consultation where a nurse or clinician explains what to expect and how to care for the site afterward.

Support services may also include:

• Wound care education: Detailed instructions on how to clean the surgical site and change bandages at home.
• Pathology services: On-site lab teams that work directly with the surgeon to check tissue samples while you wait.
• Reconstructive coordination: Access to specialists, such as plastic surgeons, if the wound requires complex repair after the cancer is removed.
• Financial counseling: Staff who can help you understand insurance coverage and potential out-of-pocket costs.

Questions for choosing where to have surgery

Choosing the right facility is an important step in your care. Your clinician may suggest a specific center, but you can also ask the following questions to help you feel more comfortable:

• Is the surgeon specifically trained in Mohs micrographic surgery?
• Does the facility have an on-site laboratory to process tissue samples during the procedure?
• Who will perform the repair or reconstruction once the skin cancer is removed?
• How many Mohs procedures does the center perform each year?
• What is the process for follow-up care if I have questions after I go home?

Conditions commonly treated by this procedure

Mohs surgery is most often used to treat the two most common types of skin cancer: basal cell carcinoma and squamous cell carcinoma. These are cancers that start in the top layer of your skin. Your clinician may recommend this procedure if the cancer is in a sensitive area where it is important to save as much healthy tissue as possible, such as the face, eyelids, nose, ears, or hands.

This technique is also helpful for skin cancers that have a high risk of coming back or those that have edges that are hard to see. In some cases, clinicians may use Mohs surgery to treat certain types of melanoma or other rare skin tumors, such as dermatofibrosarcoma protuberans.

Related symptoms people search for

People often look for information about Mohs surgery when they notice new or changing spots on their skin. These changes can be associated with skin cancer and should be evaluated by a healthcare professional. Common signs may include:

• A bump that looks pearly, waxy, or shiny.
• A flat, flesh-colored, or brown spot that looks like a scar.
• A firm, red nodule or growth.
• A sore that bleeds, crusts over, and does not seem to heal.
• A flat sore with a scaly or rough surface.

Because skin cancer can look different on everyone, any new growth or patch of skin that feels itchy, tender, or painful should be checked. Your clinician can determine if a biopsy—taking a small sample of the skin—is necessary to find out if the spot is cancerous.

Evidence overview

Mohs surgery is widely recognized by medical experts as a highly effective treatment for common skin cancers, such as basal cell carcinoma and squamous cell carcinoma. Medical literature and clinical guidelines often highlight that this technique offers the highest potential cure rate—frequently cited as up to 99% for skin cancers that have not been treated before.

A primary advantage supported by evidence is the ability to spare healthy tissue. Because the surgeon examines the edges of the removed tissue under a microscope while you are still in the office, they can ensure all cancer cells are gone before stopping. This precise process helps preserve as much healthy skin as possible, which is particularly important for sensitive areas like the face, ears, and hands.

Safety notes and individualized care

This procedure is generally considered safe and is typically performed using local anesthesia. This means the surgical area is numbed so you do not feel pain, but you remain awake. Using local anesthesia helps avoid the risks often associated with general anesthesia (being put to sleep).

While complications are uncommon, every surgical procedure carries some risk. Your clinician will discuss potential side effects with you, which may include:

• Bleeding or bruising around the wound.
• Pain or tenderness once the numbing medication wears off.
• Infection at the site, which can usually be managed with medication.
• Scarring, which is a natural part of the healing process.

Your care team will tailor the procedure to your specific needs. For example, if you take blood thinners or have other medical conditions, your doctor will provide specific instructions to ensure your safety. Always follow your clinician's guidance on wound care to support proper healing.

Sources used

The content in this section is grounded in patient education materials and clinical summaries from reputable academic medical centers and the National Library of Medicine.