Healthy Living

What is Mohs Surgery?

What is Mohs Surgery?

Skin cancer occurs when damaged cells in the skin start to divide uncontrollably forming a malignant tumor. There are three main types of skin cancer. They are basal cell carcinoma, squamous cell carcinoma and melanoma. The first two are the most common but less dangerous as they do not spread easily to other parts of the body and remain restricted to the skin making it easier to treat. Melanomas on the other hand being less common are more dangerous, can spread to other parts of the body and have the highest death rate out of all three.

The main way to treat skin cancers is to remove the tumor surgically and if necessary use additional treatment options like chemotherapy, radiation therapy, immunotherapy, targeted treatment, etc. 

Mohs surgery also known as Mohs micrographic surgery is a specialized surgical technique used in the treatment of skin cancers. This procedure was discovered by Dr. Frederick Mohs in 1930s and therefore bears his name.

Your doctor might have recommended you to have Mohs surgery to treat melanoma. Mohs surgery is like most other surgical operations, but it also uses a microscope. During this procedure, the lesion suspected to be melanoma is removed progressively and examined under the microscope to detect cancer cells. These steps are performed in a single operation.  

During a traditional surgery for the removal of a malignant tumour, the surgeon cuts the tumour along with some of the surrounding healthy tissues just to be on the safe side and to make sure that all the cancerous cells are being removed. However, it is not till after the surgery that the tumour and the surrounding tissues are examined. It is only during this process that the doctor comes to know for sure whether they got all the tumour or left some behind because the supposedly healthy tissues turned out to be cancerous or conversely, if the tumour was smaller than anticipated and too many healthy tissues were removed in the process.

In comparison to traditional surgery, Mohs micrographic surgery has a much lower rate of error and a higher success rate.

When you have Mohs surgery, the surgeon shaves a thin layer of the suspected lesion and have it mounted for viewing under the microscope. As long as the cancerous cells are present, the surgeon goes on shaving to have them viewed microscopically. This procedure is repeated until the cancer cells are no longer visible under the microscope. 

Proponents of Mohs surgery state that this procedure ensures that only skin with cancerous cells and a very minimal portion of healthy cells is removed while the majority of the healthy tissue is left behind. They also proclaim that the use of microscope during the procedure ensures the complete removal of cancer cells for a high rate of cure.

How to Determine If Mohs Surgery is Good For You

You will often find many clinics or hospitals offering Mohs surgery due to its popularity. But in most cases, you alone cannot decide to have Mohs surgery. Only a doctor can determine if Mohs surgery is ideal for your condition.

Mohs surgery is used to treat skin cancers such as basal cell carcinoma, squamous cell carcinoma, melanoma and other types of cancers affecting the face and other parts of the body. However, Mohs surgery may not provide any additional benefits to cancers that have spread already towards the lymph nodes or other areas of the body.

Anyhow, the doctor may recommend Mohs surgery for skin cancers that have one or more of the following:

  • Located in areas where minimal or no scarring is desired such as the face, around the eyes, ears, nose or mouth, arms, feet, nipples and genital areas.
  • Skin cancers that are large and aggressive.
  • Skin cancers with lesions that have irregular or poorly defined borders.
  • Skin cancers that are recurrent or have a high risk of recurrence.

If your doctor recommends Mohs surgery, go for it.

Important Things to Know About Mohs Surgery

Mohs surgery is often advertised as a precise procedure which causes minimal or no scarring and is highly effective for melanomas.

In reality, Mohs surgery is remarkably tedious and straining for the patient. Since each slice of removed lesion is prepared, mounted and visually inspected under the microscope, the procedure takes so much time that it is not unusual for the procedure to last a day especially for large and difficult tumors. Since it takes so much time, the patient must endure multiple injections of painkillers. In addition to that, it also takes a significant amount of time to reconstruct the treated area to make it look like normal skin and to prevent scarring.

Mohs surgery involves practitioners such as a histotechnician and several assisting nurses. The surgeon often serves as the pathologist and the plastic surgeon. The costs of Mohs surgery are relatively high because of the duration and the involvement of several professionals.

Note that the doctor may also order other treatments along with Mohs surgery such as chemotherapy, radiation treatments or surgery to remove nearby lymph nodes.

For best results, choose a clinic where surgeons have adequate qualifications. Doctors qualified to perform Mohs surgery are usually dermatologists who underwent and finished fellowship training at American College of Mohs Surgery (ACMS). 


Mohs micrographic surgery is a highly specialized surgery used in treating skin cancers. During this outpatient procedure (the patient does not need to be admitted to a hospital), the doctor cuts off horizontal layers of the affected skin area and mounts them immediately by freezing and staining to be examined under a microscope for cancerous cells. As long as the cancer cells are detected, more and more layers of skin are removed until a layer of cancer-free cells are seen. The advantage of Mohs surgery over traditional surgery is that the doctor can remove all the cancerous tissues while removing minimal healthy tissues in one sitting as opposed to waiting till the surgery is over in order to find out the success of tumour removal. Because of the many steps and specialists involved as mentioned before, this procedure is lengthy and expensive. The doctor will decide if Mohs surgery is the right option for you depending on the type of skin cancer, the stage it is in, the location, etc.

Key Takeaways

  • Mohs surgery is widely used as a surgical treatment for melanoma, a type of skin cancer.
  • This procedure combines surgery and the use of a microscope.
  • The surgeon progressively removes the skin which is suspected to have cancer cells, then shaves and examines them under a microscope. The procedure is concluded once the examination reveals only cancer-free tissues.