Mohs surgery, also referred to as Mohs micrographic surgery (MMS), is a special technique that utilizes both pathology and surgery to remove skin cancer in a physician’s office.
Tissue containing the tumor is frozen on a cryostat, and very thin horizontal slices of tissue are cut from the bottom-most layers of the skin tumor, positioned on a glass slide, and stained by a technician. The physician then examines these thin layers under a microscope. A dermatologist removes and examines repeated saucer-shaped layers of tissue until no more skin cancer is visible, only healthy tissue.
The procedure includes special dyes that allow the surgeon to remove the entire malignancy using a tumor map showing the sites of any residual cancer cells. During MMS there is an examination of the entire tumor’s margins simultaneously while the patient is waiting.
If more cancer cells are seen under the microscope, tissue is removed at those sites of involvement. MMS enables the examination of 100% of the entire tumor’s margin, thereby reducing the chance of recurrence of the skin cancer..
MMS is scheduled with the understanding that the patient may be spending the entire day in the office depending on the number of levels necessary to clear the tumor. You are generally in the medical office for several hours on the day of your Mohs procedure.
Depending on the size and depth of the skin cancer, more than a single level may be required to achieve clearance. MMS requires your patience and your doctor’s careful effort and skill. It is not always possible to predict ahead of time how many hours your specific procedure will take. Most patients leave their day’s schedule open to allow for adequate time to complete their Mohs procedures.