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Moles procedure: Mohs Surgery – The Skin Cancer Foundation

Mohs Surgery – The Skin Cancer Foundation

Mohs surgery is considered the most effective technique for treating many basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), the two most common types of skin cancer. Sometimes called Mohs micrographic surgery, the procedure is done in stages, including lab work, while the patient waits. This allows the removal of all cancerous cells for the highest cure rate while sparing healthy tissue and leaving the smallest possible scar.

It began as a technique called chemosurgery, developed by Frederic E. Mohs, MD, in the late 1930s, but was not widely known. In the mid 1960s, Perry Robins, MD, studied the procedure with Dr. Mohs, and recognized that it had great potential for the field of dermatology. He brought the technique to NYU, where he established the first fellowship training program to teach dermatologists this skin cancer surgery. Dr. Robins helped advance the procedure into what is now called Mohs surgery and went on to teach and promote it around the world.

  • Who performs the procedure
  • Advantages of Mohs surgery
  • What happens during Mohs surgery
  • Is Mohs right for me?
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The Advantage of Mohs

for a skin cancer that has not been treated before

Who performs the procedure?

Mohs surgery is performed by doctors who are specially trained to fulfill three roles:

  1. as the surgeon who removes the cancerous tissue
  2. as the pathologist who analyzes the lab specimens
  3. as the surgeon who closes or reconstructs the wound

Advantages of Mohs surgery

Efficient, cost-effective treatment
  • Single-visit outpatient surgery
  • Local anesthesia
  • Lab work done on-site
Precise results
  • Physician examines 100% of tumor margins
  • Spares healthy tissue
  • Leaves the smallest scar possible
The highest cure rate
  • Up to 99% for a skin cancer that has not been treated before
  • Up to 94% for a skin cancer that has recurred after previous treatment

What happens during Mohs surgery

The procedure is done in stages, all in one visit, while the patient waits between each stage. After removing a layer of tissue, the surgeon examines it under a microscope in an on-site lab. If any cancer cells remain, the surgeon knows the exact area where they are and removes another layer of tissue from that precise location, while sparing as much healthy tissue as possible. The doctor repeats this process until no cancer cells remain.

Step 1: Examination and prep

Depending on the location of your skin cancer, you may be able to wear your street clothes, or you may need to put on a hospital gown. The Mohs surgeon examines the spot where you had your biopsy and may mark it with a pen for reference. The doctor positions you for best access, which may mean sitting up or lying down. A surgical drape is placed over the area. If your skin cancer is on your face, that may mean you can’t see what’s happening, but the doctor talks you through it. The surgeon then injects a local anesthesia, which numbs the area completely. You stay awake throughout the procedure.

Step 2: Top layer removal

Using a scalpel, the surgeon removes a thin layer of visible cancerous tissue. Some skin cancers may be “the tip of the iceberg,” meaning they have roots or extensions that aren’t visible from the surface. The lab analysis, which comes next, will determine that. Your wound is bandaged temporarily and you can relax while the lab work begins.

Step 3: Lab analysis

The surgeon cuts the tissue into sections, color codes them with dyes and draws a map of the surgical site. In the lab, a technician freezes the divided tissue, then cuts very thin horizontal slices like a layer cake. The slices are placed on microscope slides, stained and covered. This meticulous process takes time.

Step 4: Microscopic examination

Using a microscope, the surgeon examines all the edges and underside of the tissue on the slides and, if any cancer cells remain, marks their location on the map. The physician then lets you know whether you need another layer of tissue removed.

Step 5: Second layer removal

Back in the operating room, the surgeon injects more anesthesia if needed and removes another layer of skin, precisely where the cancer cells remain, based on the map. Then, while you wait, the lab work begins again. This entire process is repeated as many times as needed until there are no more cancer cells.

Step 6: Wound repair

Once the site is clear of all cancer cells, the wound may be left open to heal or the surgeon may close it with stitches. This depends on its size and location. In some cases, a wound may need reconstruction with a skin flap, where neighboring tissue is moved into the wound, or possibly a skin graft. In some cases, your Mohs surgeon may coordinate the repair of your wound with another specialist such as a plastic surgeon, oculoplastic surgeon or hand surgeon. In most instances, however, the Mohs surgeon will repair the wound immediately after obtaining clear margins.

Step 7: Finishing up

If more than one or two rounds are needed, the entire process can take up to several hours, so be prepared for that. It’s worth it, though, because this precise technique has the highest cure rate of any treatment method and can save the greatest amount of healthy tissue, leaving the smallest scar possible. Carefully follow your doctor’s instructions for wound care, scar care and follow-up to achieve the best outcome.

Is Mohs right for me?

Mohs surgery is the gold standard for treating many basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), including those in cosmetically and functionally important areas around the eyes, nose, lips, ears, scalp, fingers, toes or genitals. Mohs is also recommended for BCCs or SCCs that are large, aggressive or growing rapidly, that have indistinct edges, or have recurred after previous treatment. Some surgeons are also successfully using Mohs surgery on certain cases of melanoma.

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Mohs: The Gold Standard – The Skin Cancer Foundation

By Arielle N.

B. Kauvar, MD

Mohs surgery is on the rise, for good reasons: It has the lowest recurrence rates, highest cure rates and best cosmetic results of any skin cancer treatment. A physician member of The Skin Cancer Foundation explains why Mohs has it all.

Lifesaving new medications for people with advanced melanoma, called targeted therapies and immunotherapies, have grabbed the biggest skin cancer headlines in the past few years, and that’s good news. But for people with the more common nonmelanoma skin cancers, basal cell and squamous cell carcinoma (BCC and SCC), an older technique has also been drawing more attention and favor than ever. I recently led the task force to establish consensus guidelines on the treatment of BCC and SCC, which were published this year. They demonstrate that Mohs surgery is the treatment of choice for many BCCs and SCCS, and the single most precise and effective method for eliminating these cancers.1-3

Did you know your chance of developing a nonmelanoma skin cancer in your lifetime is about one in five? More than 5. 3 million cases of BCC and SCC are diagnosed in the U.S. each year. Exposure to ultraviolet (UV) light, either from the sun or from indoor tanning, is the greatest risk factor for developing these skin cancers, so it’s not surprising that approximately 80 percent of these cancers occur on the head and neck, where exposure is greatest. Unfortunately, since these are the most conspicuous skin cancers, they are also the most cosmetically challenging, capable of becoming disfiguring and sometimes dangerous if not caught at an early stage.

That’s why I want you to know just what Mohs surgery is, how it works, and what it can do to leave you cancer-free while looking the best you can after surgery.

How Mohs surgery works

Sometimes known as Mohs micrographic surgery, the technique was invented in the 1930s by Dr. Frederic Mohs at the University of Wisconsin, but it didn’t develop into a mainstream treatment until practitioners such as NYU dermatologist Perry Robins, MD, refined the technique and spread the word about it in the 1970s and 1980s. The use of Mohs surgery has especially been growing in the past 15 years, above all for skin cancers in the head and neck region.2-5

The most obvious difference between Mohs surgery and routine excisional surgery is that Mohs is done in stages while you wait for lab results, which are obtained immediately on site, rather than the tissue sample being sent to a lab for results days later.

A surgeon specially trained in Mohs surgery, pathology and reconstructive surgery first may draw some marks around the lesion with ink to guide the treatment, then injects a local anesthesia. Using a scalpel, the doctor removes the thinnest possible layer of visible cancerous tissue. (Sometimes doctors gauge this by feel as well as by sight.) A nurse or assistant bandages your wound and shows you to a waiting area.

The surgeon then color-codes the tissue with ink to map exactly where it was removed from the body. Next, a technician processes the tumor in the on-site laboratory by freezing the tissue so that it can be readily cut into paper-thin sections (like a stack of dimes) and placed on slides. The tissue on the slides is then stained and the Mohs surgeon examines these slides under a microscope. If the doctor finds any remaining cancer cells, the areas are pinpointed on the map, and you’re called back into the operating room. The doctor numbs those areas again before precisely removing another layer of tissue from each of the locations where cancer cells remain.

Some Mohs surgery steps

Arielle Kauvar, MD, examines a cancerous area on the side of the patient’s nose.

Before starting the surgery, Dr. Kauvar injects a local anesthetic.

Dr. Kauvar removes the first layer of cancerous tissue.

In the lab, the surgeon examines slides with sections of the removed tissue.

Next, she marks a map of where cancer cells remain before round two of surgery.

Bandaged, the patient waits for the lab results before another round of surgery. It takes time to get the all-clear, but it’s worth it!

The team repeats this whole process until the margins (edges) of the last excised tissue sample are clear and cancer-free. At that point, the doctor usually closes the wound with stitches. In some cases, a large wound on the face or around a joint may need reconstruction with a skin flap or a skin graft. Mohs surgeons are trained in these techniques, though in some cases, a plastic surgeon may do the reconstruction or closure. After that, the wound is bandaged, you’re given instructions on how to take care of the incision — and you’re done.

As you can imagine, all of this takes time. If you need several rounds, it may take several hours. But the time spent is worth it. The Mohs process examines 100 percent of the tissue margins under the microscope, whereas in standard surgical excision only 1 percent of the margins are examined microscopically. Mohs surgery also conserves the greatest amount of healthy tissue, giving you the smallest scar possible. The procedure is cost-effective because the cancer removal, microscopic evaluation and, in most cases, wound reconstruction are all done in one visit, and the cure rate is up to 99 percent.

Who should have Mohs?

Because of its high cure rate, Mohs surgery is now recommended as the treatment of choice for high-risk nonmelanoma skin cancers.1-3 Cancers on the nose, eyelids, lips, ears, hands, feet and genitals (some skin cancers are related to genetics or other causes rather than UV exposure) are all considered high-risk. Those on other areas of the face, scalp, neck and shins are considered intermediate risk.

Other skin cancers also best treated with Mohs surgery include:

  • large cancers in normally low-risk areas.
  • those with difficult-to-see borders.
  • those with certain microscopic growth patterns.
  • those that have recurred after initial treatment.
  • those that could not be completely removed.

Mohs surgery is the front-line treatment for nonmelanoma skin cancers that grow in scar tissue or areas of prolonged inflammation, as well as skin that had previously been treated with radiation. Nonmelanoma skin cancers are also considered high-risk when they develop in patients whose immune systems are suppressed by medication (such as transplant recipients) or disease (such as leukemia), or in those with genetic syndromes that predispose them to skin cancers.

For small or superficial low-risk BCCs and SCCs on the abdomen, chest, back, arms and legs, standard treatments such as surgical excision, cryosurgery (freezing), curettage and electrodesiccation (scraping and burning), photodynamic therapy and topical medications may provide adequate therapy. (For more details on these procedures, see The Skin Cancer Foundation’s Treatment Glossary.)

Younger People Benefit, Too

The number of people who develop skin cancer has been increasing for decades, and, alarmingly, more women and men under age 40 are now being diagnosed with the disease. Particularly in women, indoor tanning has been linked by many experts to an increased incidence of skin cancers at younger ages.

In my practice, I treat at least one patient in his or her 30s each week with Mohs surgery and many in their 40s and 50s, which is vastly different than 20 years ago, when the majority of patients were older. Not many young people seriously worry about getting skin cancer. Many use tanning beds and skip sun protection, and if they discover an unusual growth on their skin, they often delay seeking treatment because they think it’s no big deal. But it can be. Basal cell carcinomas rarely metastasize, or spread through the body, but some have aggressive growth patterns and can cause significant damage by growing along nerves or blood vessels, or through muscle or bone. By allowing the cancer to grow, you risk requiring more extensive surgery in the future. Squamous cell carcinomas can be more dangerous, carrying an approximately 4 percent risk of metastasis and 2 percent risk of death6, and the risk increases when these cancers return after treatment.

That’s why it’s crucial for you to start as early as possible to protect yourself from the sun (see The Skin Cancer Foundation’s protection tips) and to start making a professional skin exam an annual habit. You should also check your own skin once a month head to toe, and get to a dermatologist immediately if you find any new or changing spot on your skin. It’s especially important to be aware that once you have had a skin cancer, you are at increased risk of one day developing new skin cancers elsewhere on the body.

It’s scary at any age to think about skin cancer surgery, especially when the cancer is on your nose, lips, ears or eyelids; it stirs up fears of scarring and disfigurement. Skin cancers in these critical locations have a high risk of recurring after treatment with standard techniques, and when they do recur they can require more extensive surgery because of undetected growth beneath the skin’s surface. Mohs surgery delivers the best cosmetic results, the lowest recurrence rate of any treatment method — and the highest chance of a complete cure. That’s good news at any age.

Arielle N.B. Kauvar, MD

Arielle N.B. Kauvar, MD, is founding director of New York Laser & Skin Care and a clinical professor, Ronald O. Perlman Department of Dermatology, NYU Langone Medical Center in New York City. She is a member of The Skin Cancer Foundation’s Robins Fund.


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Mohs surgery Step by Step

Radio wave mole removal

  • Removal in a modern way in 1 visit (with a preliminary consultation with a dermatologist).
  • Minimal tissue damage, fast healing.
  • Removal is carried out at a given depth, as quickly and comfortably as possible, using the Surgitron apparatus.
  • Relatively painless (local anesthesia is possible).
  • Analysis of material after removal (if indicated)
Consultation with a dermatologist on the day of tumor removal using a dermatoscope up to 2 units. 1200 rub
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Features of procedure

Large moles are removed under local anesthesia. When an anesthetic is injected into the skin nearby. Small moles, red, can be removed without anesthesia.
In one session, the doctor will almost always be able to remove all disturbing moles with the radio wave method.
The terms of wound healing after radio wave removal are much shorter than when removed by other methods. On the face and neck, it takes only a few days for small moles to heal. Other areas may require more time.
It is better to sign up for the procedure in advance so that the doctor takes his time and can prepare the equipment.

Preparation and process

Radio wave removal does not require special preparation. You may need to remove the hair near the mole with depilatory cream or shave it carefully. It will also be good to calm down and sleep well.

Description of the process
During the procedure, the doctor removes the tissues of the mole to the required depth with a radio wave device. Removal is almost bloodless. The wound after the procedure either remains as it is, or is sutured with a large depth and size of the mole. The main advantage of radio wave removal is that you can get rid of a mole of any depth, of considerable size, if you replace the resulting wound with skin located nearby or moved from other areas. A mole removed by the radio wave method can be fully examined under a microscope, to find out if there are foci of degeneration into melanoma or skin cancer, its cells are not damaged during the procedure.

What to do after removal
Wound care prescribed by a doctor. Perhaps these will be ointments for faster healing (d-panthenol, methyluracil and others), antiseptics (povidone-iodine, potassium permanganate), antibiotics (levomekol, baneocin). In each case, this is determined individually.

Moles are dangerous
Moles are dangerous because they can develop into melanoma or skin cancer. The most common variant of a mole turns into melanoma – a common nevus, a blue nevus, and a congenital nevus. Epidermal, sebaceous nevus, seborrheic keratosis can turn into skin cancer. Of course, the probability of such a development of events will differ in each case. However, the fewer moles there are, the lower the risk of skin cancer or melanoma.

Patients refer to a variety of benign tumors on their skin as moles. The task of the doctor: to determine the exact name and nature of the mole. That is, to establish the correct diagnosis. Many features of the radio wave removal of a mole depend on the diagnosis. Common moles are nevi, red angiomas, seborrheic keratosis, and dermatofibromas. Among the nevi, there are several varieties that are very different from each other.


Surgitron and radio wave devices of other brands work due to the action of very high frequency radio waves. They cut tissue bloodlessly and evenly. At the same time, there is no heating of the skin and subcutaneous tissue, there are no partially damaged areas. Wounds heal much faster and there is less scarring when there are no partially burned tissues around. Many nozzles and modes of operation of the devices allow you to perform a variety of medical procedures. Including, remove moles with different approaches, depending on its variety. Radio wave devices serve as a modern replacement for conventional scalpels. There are models that are used during abdominal operations under anesthesia. However, radio wave devices are expensive and difficult to repair.

Consultation with a dermatologist on the day of tumor removal using a dermatoscope up to 2 units. 1200 rub
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Popular questions

What is the difference between radio wave removal and laser removal?

Radio wave removal involves even cutting off a piece of skin with a mole under the action of radio waves. The cut piece remains almost intact. It can be fully examined under a microscope. Laser removal of a mole vaporizes the tissues of the mole in small parts. After it, there is nothing to examine under a microscope. Radio wave removal allows you to remove the mole very deeply and widely, and the resulting wound can be sewn up. After laser removal, the wounds are not sutured.

What is the best way to remove moles?

There is no one way that is perfect for everyone. The most versatile radio wave method. It allows you to remove moles without burning or injuring healthy tissues. Healing after removal by the radio wave method is relatively fast and of high quality. It allows you to remove moles of any type, and even with a histological examination, if necessary.

What is the best way to remove moles with a laser or radio waves?

In most cases, there will be no difference between the two methods in terms of either healing speed or cosmetic results. However, for a certain number of moles, the possibility of a complete examination under a microscope (histological), which can only be provided by radio wave removal, will be important. Also, with the help of radio wave removal, it is possible to get rid of large and deep moles by closing the resulting wounds with tension with sutures or even a skin flap.

Why is radio wave mole removal better than electrocoagulation?

Electrocoagulators generate intense heat and burn tissue when removed. Heat causes additional pain. Heat-damaged tissues are more likely to suppurate during wound healing. More scar tissue forms, which can lead to keloid and hypertrophic scarring.

Is it possible to sunbathe in the sun or in a solarium with moles?

Sunbathing with moles is not worth it. Sunlight contributes to further damage to the DNA of the cells of moles, already previously damaged. Everything can result in the formation of melanoma or skin cancer, depending on the type of mole. Even if it is glued, the hormones produced from sunburn in other places of the skin will still stimulate the reproduction of pigment cells with approximately the same consequences.

Can moles reappear after being removed?

It is possible for the mole to reappear after removal if it is not carried out deep enough and all pigment cells are not captured. Also, the reappearance often indicates possible errors in the diagnosis, when the mole turned out to be actually melanoma or skin cancer.

Laser mole removal

Moles are a diagnosis made by patients themselves. In medicine, there is a group of benign skin tumors with corresponding names, which are determined by doctors when patients come to them with “moles”. Most often, nevi of various varieties, angiomas (red moles), seborrheic keratosis, dermatofibroma are detected. Much less often, melanoma or skin cancer is hidden under the mask of a “mole”. Before removing a mole with a laser, it is necessary to clearly define the diagnosis. Sometimes, this requires a dermatoscopy, scraping or even a biopsy.

Consultation with a dermatologist on the day of tumor removal using a dermatoscope up to 2 units. 1200 rub
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Laser removal of single benign neoplasms (nevus) up to 5 mm, for 1 unit. 1800 rub
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Laser removal of single benign neoplasms (nevus) more than 5 mm, for 1 unit. 2600 rub

Features of procedure

Laser mole removal is most often performed under local anesthesia with the injection of lidocaine or another drug into the skin under the mole. Small seborrheic keratosis or red moles may not be anesthetized.
If there are not very many moles or they are all small in size, then they can be removed with a laser in one session. It is necessary to limit the dose of the administered local anesthetic in accordance with the instructions due to the possibility of side effects. If the painkiller limits are reached, the removal of the remaining moles is transferred to the next session.
The healing rate of moles after laser removal varies greatly depending on the size, location, depth. It ranges from a few days to a month. Moles on the face heal the fastest. The slowest is on your feet.

It is necessary to register in advance for the removal of a mole with a laser so that it is possible to prepare the device to allocate time for the procedure in the schedule.

Preparation and process

Before laser removal, it is advisable to get enough sleep, if necessary, drink a sedative in the evening. It will not be superfluous to get rid of the hair around the mole with a depilatory cream or to shave the hair neatly.

Description of the process
During removal by laser beams, the tissues of the mole itself evaporate (vaporization), and then the pigment cells at its base (if it is a nevus). The depth of laser exposure and power will be different depending on the type of mole, it is determined by the doctor.

What to do after removal
After laser removal of a mole, your doctor may prescribe ointments or medicines to care for the wound. These can be means to accelerate wound healing, antibiotics to prevent infections, means to improve the appearance of scars. To wet or not to wet wounds from moles is also determined by the doctor.

Why are moles dangerous?

Pigmented nevus moles may develop into melanoma over time. Sometimes, they grow in breadth for many years, do not bother with anything else. However, as soon as nodular melanoma is formed, the mole becomes convex, begins to bleed or even metastasize throughout the body. Nodular melanoma is a very common cause of death. Melanoma itself is not removed by laser. However, many nevi, which are possible precursors of melanoma, can be removed with a laser. From moles such as seborrheic keratosis or nevi without pigment cells, skin cancer (basal cell and squamous cell) can form. Skin cancer is not as dangerous as melanoma. But, people often die from it. It is easier to remove moles with a laser without waiting for them to turn into something more dangerous.

Consultation with a dermatologist on the day of tumor removal using a dermatoscope up to 2 units. 1200 rub
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Laser removal of single benign neoplasms (nevus) up to 5 mm, for 1 unit. 1800 rub
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Laser removal of single benign neoplasms (nevus) more than 5 mm, for 1 unit. 2600 rub

Laser Removal Equipment

There are several classes of laser machines for removing moles. The most commonly used diode laser. Beams of light with the desired wavelength are formed inside the apparatus, and from there they go through the light guide to the mole. The wavelength of the laser light is selected so that it is primarily absorbed by water or blood, that is, it heats them up very quickly. From the rapid heating of the laser, the water from the mole instantly evaporates and the skin around or the fatty tissue under it does not heat up. The less healthy tissues are heated, the faster the wound heals and the less scarring.

Popular questions

How long does it take for a wound to heal after laser removal of a mole?

The rate of wound healing after laser removal of a mole will depend on many different factors: the size, type of mole, location, presence of concomitant diseases. With small size and shallow depth (red moles), healing can take about a week. Typical moles (shallow intradermal nevi) on the face up to 1 cm in size heal within two weeks. However, there are often moles, after the removal of which by laser healing will take about a month.

Can moles be removed with a laser?

Most moles can be laser removed with excellent cosmetic results. An exception is made in rare cases. For example, when a mole looks like a basal cell or melanoma. In such situations, the patient is sent for a consultation with an oncologist to rule out malignant skin lesions. A scraping or biopsy may be needed to make a definitive diagnosis.

Which moles should not be removed?

All moles can be removed. There are moles, before removing which you need to fully determine the diagnosis and also choose the best method. To do this, they can be sent for a consultation with an oncologist, where a biopsy or scraping is performed. If the mole turns out to be malignant or precancerous, it is all the more necessary to remove it. However, the removal methods will be very different from those that are acceptable for ordinary moles. The decision is made by the doctor.

Which is better, laser or radio wave mole removal?

in each case, the method of removal is determined by the doctor. There are moles that can be removed with a laser that may not be effective. These can be deep congenital nevi, nevi suspicious for melanoma, it is desirable to examine them under a microscope in their entirety and remove them to the full depth. There are few such moles. For their removal, a radio wave method or a surgical method is used. On the other hand, there are red moles, superficial seborrheic keratosis, which are best removed superficially with a laser.

They say that moles should not be touched, otherwise you can die from it. Is this true?

Many of our potential patients think so and continue to grow various moles and other neoplasms on their skin.