Posted by Kali Glover & filed under .


One in five Americans will develop skin cancer over their lifetime. With skin cancer affecting so many people, treatments for skin cancer are becoming more advanced. Procedures like Mohs Surgery help doctors diagnose and treat skin cancer in a precise way. So, what is Mohs Surgery?

Mohs surgery is a highly effective treatment for certain types of skin cancer. It is an exacting procedure in which the dermatologist performs both surgical excision of the skin cancer and microscopic examination of the surgical margins to ensure that all skin cancer cells have been removed. The excised tissue from the patient is brought to our in-house Mohs Laboratory by the surgeon or medical assistant. Our Mohs tech then logs in the patient’s information which includes name, case number, site, and diagnosis. The surgery consists of five steps: Grossing, embedding, cutting, staining and diagnosis.

This process begins with removal of the specimen. The process of determining this is called grossing, in which the dermatologist makes “relaxing cuts” in order to relax the removed tissue and get it to lie flat to be examined. Once the tissue is grossed, it is inked with several colors—blue, red, yellow or green—for orientation, much like a compass, to ascertain the actual site of cancer more accurately.

The specimen is then manipulated into a mold and placed into a Cryostat that helps make a “block” by freezing the tissue. This step is called embedding. The Cryostat is set to -24 °C to – 28 ° C. With the tissue in the mold, a generous amount of Tissue Freezing Medium (TFM) is squeezed over the tissue and topped with a chuck. After embedding, the cutting process can begin in the Cryostat, known as the cryochamber. First, there is a “rough cut” made on the specimen in order to achieve a flat and even plane. Next, the surgeon starts cutting minuscule sections of 3 to 5 microns, depending on the tissue’s thickness. To put it into perspective, the thickness of a human hair is about 50-100 microns. After what is typically 8 slices made, each margin of the tissue is meticulously examined. When all slides are done, they are placed in a series of chemicals, also known as H&E staining (Hematoxylin & Eosin). Hematoxylin stains the nucleus of the cell and Eosin (referred to as a counter stain) which stains nearly everything that the hematoxylin does not. This process takes about 5 minutes.

The diagnosis procedure begins when the stained slides with the corresponding paperwork is then given to the surgeon to be read under a microscope. The diagnosis can be clear or if there is more tumor seen the surgeon will then remove another layer from just the site where the cancerous cells are present, which is documented as a stage II and the process is repeated.

Mohs is a highly effective treatment for certain types of cancer, with a cure rate of up to 99% for certain cancers. Diligently examining the unhealthy tissue while sparing the healthy, remaining tissue, Mohs is one of the least invasive skin cancer treatments. Compared to other treatments, it has the least downtime and less noticeable scarring.

Find out if Mohs Surgery is right for you and your skin cancer treatment. Talk to one of our providers at Collins Advanced Dermatology Institute or book an appointment online.