What is Mohs micrographic surgery (MMS)? Why is the procedure called Mohs?
Mohs micrographic surgery is a minor surgical procedure and special method of removing skin cancers using local anesthesia (numbing). The majority of cases are performed in the physician’s office. Mohs is a very precise, highly detailed technique whereby small layers of skin are sequentially removed and immediately examined under the microscope until the samples indicate that the skin cancer is completely removed.
The procedure uses frozen sections of skin that are then stained with special dyes. The dyed frozen pieces of skin are further examined under the microscope and a tumor map is drawn by the Mohs surgeon. The freezing process allows an immediate examination of the entire tumor margin and tissue histology (microscopic examination of cells).
If more cancer cells or “roots” are seen under the microscope, then another skin layer is removed and again examined. Each skin layer that is removed is called a “level.” If no more cancer roots are seen, then it is called “clear” (no more tumor) and no additional levels are needed.
By removing only tissue where cancer is known to be present, the technique combines a very high cure rate with good preservation of normal skin. Once the cancer has been fully removed, the Mohs surgeon looks at the wound to determine the method to obtain the best wound repair and cosmetic result for you.
Mohs is special because the entire edge and undersurface of each skin cancer layer is carefully examined under the microscope for the presence of very small cancer cells. With regular or traditional surgery, only about 1%-3% of the tumor margins are actually examined, thereby increasing the chances that a small tumor root would be missed and left behind. Mohs allows for examination of 100% of the tumor margins thereby reducing the chance that tumor cells will be left behind.
Mohs is usually scheduled only on certain days in the doctor’s office because of the required equipment, tissue stains (dye), Mohs technologists, and microscopes. Most of these procedures are generally performed with the patient waiting in the office for the tissue to be “read” or interpreted by the Mohs surgeon.
Mohs is named after its inventor, Dr. Frederic Mohs, who first described the technique in 1941.
Mohs Surgery at Dr. Plateroti Dermatology Associates
At Dr. Plateroti Dermatology Associates, Mohs Micrographic Surgery is performed as an outpatient procedure in the physician’s office. The patient is awake during the procedure. For the surgery, a local anesthetic is used to numb the area, after which the doctor removes the visible cancer and takes it for processing. Once the tissue is processed, the doctor examines the slides to determine if any cancer remains. If residual cancer is found, the doctor will remove additional cancer only where the cancer is still present. Then the processing will start again. If the cancer has been removed completely, then the site is ready to be repaired. There are several options of how to repair the defect, and the doctor will discuss these with the patient and help determine which is best for them.