Micrographic Skin Surgery

Micrographic skin surgery is a highly specialized technique for removing skin cancer while preserving as much healthy tissue as possible, offering the highest cure rates and minimal scarring.

Mohs surgery, Mohs micrographic surgery

Table of contents

• What is Micrographic Skin Surgery?
• History and Development
• How the Procedure Works
• Conditions Treated
• Advantages of the Procedure
• Who Performs the Procedure
• What to Expect During the Procedure
• Possible Risks and Complications
• Recovery and Aftercare
• Success Rates

What is Micrographic Skin Surgery?

Micrographic skin surgery, also called Mohs surgery or Mohs micrographic surgery, is a precise method used to remove skin cancer^[1]. This surgery involves cutting away thin layers of skin, with each layer carefully examined under a microscope for signs of cancer^[1]. The process continues until there are no signs of cancer remaining.

The main goal of this procedure is to remove all cancerous tissue without hurting the healthy skin around it^[1]. This approach allows the surgeon to be certain that all cancer is gone, which makes it more likely that the cancer is cured and reduces the need for additional treatments or more surgery^[1].

The procedure is considered the most effective technique for treating many basal cell carcinomas (a common type of skin cancer starting in the base layer of skin) and squamous cell carcinomas (cancer that begins in flat cells on the skin’s surface)^[2]. It offers high cure rates while sparing healthy tissue and leaving the smallest possible scar.

History and Development

The technique was developed by Dr. Frederic E. Mohs in the 1930s^[3]. Originally, the procedure was called “chemosurgery” because it involved applying a chemical fixative (zinc chloride) to the tumor for 24 hours before removing it^[3]. After removal, the tissue was examined under a microscope, and the process was repeated until the tumor was completely removed.

Over the following decades, the technique evolved away from using chemical fixation. Instead, doctors began processing fresh tissue that was frozen and sliced in a special machine called a cryostat microtome^[3]. This new approach offered several advantages: faster processing times (about 15 to 30 minutes), less patient discomfort, and better preservation of healthy tissue.

In the mid-1960s, Dr. Perry Robins studied the procedure with Dr. Mohs and recognized its great potential for dermatology^[2]. He brought the technique to New York University, where he established the first training program to teach dermatologists this specialized surgery. Dr. Robins helped advance the procedure into what is now called Mohs surgery and promoted it around the world.

How the Procedure Works

Micrographic skin surgery is performed in stages, with each stage designed to ensure complete cancer removal^[2]. The procedure begins with the doctor applying medicine to numb the area, so the patient doesn’t feel pain during surgery^[1]. Most patients receive local anesthesia and can go home after the procedure without needing to stay in a hospital.

First, the surgeon removes the visible part of the tumor along with a thin layer of tissue around it, typically with margins of about 2 millimeters of normal skin^[3]. The removed tissue is marked with colored dye to specify its position and orientation. The specimen is usually removed with a 45-degree angle cut to make tissue processing easier^[3].

The tissue sample is then taken to an on-site laboratory where it is rapidly frozen and cut into very thin horizontal sections^[3]. Cutting the tissue horizontally is important because it allows the doctor to examine virtually 100 percent of the tissue edges under the microscope, including both the sides and bottom of the sample. This is different from standard tissue removal, where less than 1 percent of the margins are typically checked^[5].

While the patient waits, the surgeon examines the tissue samples under a microscope^[2]. This usually takes about 45 minutes. If cancer cells are found at any of the edges, the surgeon marks their exact location on a map. The patient is then brought back for removal of another thin layer of tissue only from the areas where cancer was detected^[5].

This cycle repeats until no cancer cells remain^[4]. On average, two stages are required to completely remove most tumors, though some may require more^[3]. Once all cancer is removed, the surgeon decides how best to treat the wound to help the patient regain maximum function and appearance.

Conditions Treated

Micrographic skin surgery is used to treat various types of skin cancer^[1]. It is most commonly used for basal cell carcinoma and squamous cell carcinoma, the two most common types of skin cancer^[5]. The procedure is also sometimes used to treat melanoma and other less-common skin cancers.

This surgery is particularly useful for skin cancers that have certain characteristics^[1]:

• Cancers that have a high risk of coming back or that have returned after previous treatment
• Cancers in areas where preserving as much healthy tissue as possible is important, such as around the eyes, ears, nose, mouth, hands, feet, and genitals
• Cancers with edges that are hard to define
• Cancers that are large or grow quickly

The tissue-sparing properties of this surgery make it particularly useful in areas of functional and aesthetic importance, such as the head and neck area, the genital area, hands, and feet^[3].

Advantages of the Procedure

Micrographic skin surgery offers several important advantages compared to other methods of treating skin cancer. The main advantage is that it provides precise microscopic control of the entire tumor edge while keeping as much healthy tissue as possible^[3].

The procedure is efficient and cost-effective^[2]. It is typically completed in a single visit as outpatient surgery, with local anesthesia used to numb the area. Laboratory work is done on-site, allowing for immediate results.

Because the surgeon examines 100 percent of the tumor edges under the microscope, the procedure is extremely precise^[2]. This thoroughness means that healthy tissue is spared and the smallest possible scar is left. This is especially important for cancers located on the face and other visible areas.

The procedure has the highest cure rate of any treatment for skin cancer^[2]. For a skin cancer that has not been treated before, the cure rate can reach up to 99 percent. Even for skin cancers that have come back after previous treatment, the cure rate is up to 94 percent. This is significantly higher than other treatment methods and represents the lowest recurrence rate^[5].

Who Performs the Procedure

Micrographic skin surgery is performed by doctors who have received special training to fulfill three important roles^[2]:

• As the surgeon who removes the cancerous tissue
• As the specialist who analyzes the laboratory specimens
• As the surgeon who closes or reconstructs the wound

This specialized surgery requires extensive training beyond standard medical education. Surgeons who perform this procedure have completed medical school, an internship, and three years of dermatology training^[6]. They are then accepted into a competitive fellowship program where they receive special instruction in the technique.

Not all dermatologists perform this surgery^[8]. The procedure is complex and requires a skilled dermatologist with advanced training and specialized equipment. Only doctors who are board-certified in dermatology or a related field and have received additional fellowship training in the technique should perform the surgery.

What to Expect During the Procedure

Most people who undergo micrographic skin surgery are treated on an outpatient basis, meaning they can go home the same day^[3]. The procedure is done in a doctor’s office or outpatient surgical center^[5].

Before the surgery, patients see their dermatologist for a physical examination of the site and surrounding tissue^[5]. The doctor will review the patient’s medical history and medications.

On the day of surgery, the process begins after the area is marked, cleaned, and numbed with local anesthesia^[4]. Occasionally, doctors may add oral sedation for patient comfort. Any residual tumor that remained after the initial biopsy is scraped away, which helps the surgeon better predict the cancer’s borders.

After each layer of tissue is removed, patients wait in a waiting room or the operating room while the care team prepares slides and the surgeon examines them^[5]. This can take about 45 minutes. If the surgeon finds tumor at any of the edges, the patient will be brought back so another layer of tissue can be removed for further examination.

While many procedures are finished in several hours, it is advisable to allow a whole day, as it is difficult to predict the extent of the tumor and reconstruction needed before starting^[8]. Patients should bring a book or electronic device to keep occupied while waiting.

The actual process of removing the skin cancer and reconstruction should be painless due to the anesthesia^[8]. Patients may experience minor discomfort during the injection of local anesthesia, similar to what was likely done when the lesion was first tested.

Possible Risks and Complications

Like any surgical procedure, micrographic skin surgery has some risks, though serious problems are uncommon. The most common problems that can happen during and after surgery include^[1]:

• Bleeding from the surgical site
• Pain or tenderness around the places where surgery was done
• Infection at the surgical site

Other problems can happen but are less common^[1]. These may include temporary or permanent numbness of the surgical area. This can occur when small nerves in the skin are cut during the procedure.

Recovery and Aftercare

After micrographic skin surgery, proper wound care and following the doctor’s instructions are essential to prevent complications. The surgeon will provide detailed instructions for care after the procedure^[8]. Patients will also be taught how to treat their surgical wound at home.

Most patients can return to work the next day and resume exercise the following week^[8]. Some soreness may be experienced on the day following the procedure. Pain is typically managed with over-the-counter medications.

Patients should avoid sun exposure and wear high-protection sunscreen when outdoors, as sun exposure can slow healing and cause further damage to the skin. Other important precautions include avoiding makeup, creams, oils, or perfumes on the wound, not submerging the wound in water (swimming pools, baths, or the ocean), and avoiding strenuous activities until the doctor gives permission.

Any time skin is cut, there will be a scar^[8]. Depending on the size of the wound after surgery, the surgeon may close it with stitches, use a skin flap or graft, or in some cases allow the wound to heal on its own. The surgeon will remove any stitches and monitor recovery closely. Patients may receive additional follow-up care through their dermatologist.

Success Rates

Micrographic skin surgery is recognized as the skin cancer treatment with the highest reported cure rate^[15]. The procedure has an exceptionally high success rate in treating common forms of skin cancer.

For basal cell carcinoma and squamous cell carcinoma that have not been treated before, the cure rate can be as high as 99 percent^[2]. This represents a five-year cure rate, meaning patients remain cancer-free for at least five years after treatment^[3].

Even for skin cancers that have returned after previous treatment, the cure rate remains impressively high at up to 94 percent^[2]. This makes micrographic skin surgery particularly valuable for treating difficult or recurring cancers.

The high success rate is due to the methodical manner in which tissue is removed and examined. Because the surgeon can examine 100 percent of the tissue edges microscopically, no cancer cells are left behind. This thorough approach gives patients the lowest recurrence rate of any treatment for skin cancer^[5].

Patients who have had one skin cancer are at risk for developing another^[8]. For this reason, doctors recommend that patients with a history of skin cancer have regular check-ups with their dermatologist to monitor for any new cancers.