Educational video explaining Mohs Surgery for basal cell carcinomas. This video was developed for the patients of the East Kent University NHS Hospital in the United Kingdom.
This is a video about Mohs Micrographic Surgery. We will explain the concepts of Mohs and talk about what it involves. Mohs surgery is usually used to treat Basal Cell Carcinomas. These are slow-growing skin cancers that don’t spread. However, if left long enough they will grow bigger and need more surgery leading to larger scars so they’re best removed early. Mohs surgery can also be used for other tumors. The majority of basal cell carcinomas grow in a predictable fashion and what one sees on the skin usually reflects what is taking place under the skin, therefore when we cut one out like this, as an ellipse, we rarely leave any cancer behind. However in some cases we suspect the basal cell
carcinoma may be spreading under the skin and this is where Mohs Micrographic surgery comes in.
Originally developed by Frederic Mohs, an American surgeon in the 1930’s, it has since been modified. It is the most accurate method of completely removing all of the skin cancer and it also leaves smaller wounds than other techniques and importantly less scarring. Basal cell carcinomas rarely ever split apart therefore if there’s no cancer at the margins of the skin we remove, we’re confident that all of the cancer is within the sample and none remains in the patient.
Our pathologists can analyze most of a sample and estimate how likely this is, but we may have to wait a number of weeks for their report, by then the wound has already been repaired and healed. The advantage of Mohs is that it allows us to check all the margins of the sample under the microscope the same day, before we close the wound. Here is a basal cell carcinoma on the skin and it’s not obvious how far it extends. When performing Mohs micrographic surgery rather than cut out an ellipse, we cut out a disc of tissue. We also make small nicks in the skin to help orientate the sample later. The Mohs surgeon is only interested in the underside of this disc. If there is no cancer here then it has been completely removed. Depending on its size and location, additional nick’s might be added and these can be marked with special dyes. The sample can also be divided into smaller pieces, this way the surgeon can work out where in the wound any given part of the sample originally came from. The sample is then flattened and frozen solid and as a result we have a flat surface that represents the entire surgical margin of the specimen.
Thin cuts are sliced from the surface and placed on a slide for staining. The slices are bathed in special staining stations but make the cancer cells easier to see. The Mohs surgeon studies these slices under the microscope. If cancer is seen at the margin of the sample and it is likely some is still present in the patient, the most surgeon uses diagrams to work out where in the wound the cancer might still remain. That particular part of the wound is targeted and removed. When you receive your appointment for Mohs surgery, it will usually be scheduled irst thing in the morning or first thing in the afternoon. A small minority of patients are given two appointments, one for the Mohs surgery where we remove the tumor and a second with our colleagues at a different ward or site for the repair of the wound.
You must have the tumor removed by Mohs before the wound is repaired, so always attend your Mohs appointment with dermatology first. You will be asked to sign a consent form to show that you understand the purpose of the procedure and the important associated risks. Potential risks include scarring, a small risk of bleeding or infection and very rarely recurrence. Mohs surgery is carried out under local anaesthetic. The injection used to numb the skin can sometimes sting, however the remainder of the procedure should be relatively painless. Because of the time it takes to process the samples of skin you may find yourself having to wait for periods of time in the waiting area. You might want to bring along something to read because Mohs allows us to identify when the cancer has spread further than we had thought. The size of your scar may be larger than you expected. Depending on the size and location of the wound, we will try to close it into a single line like this, however sometimes we must do more complicated repair procedures that may involve extending the scar in other directions so that we can free up nearby skin to cover the wound. We will hide the scar as best we can so that it’s less obvious. After the wound has healed, in some cases, we may use skin from another area your body to fix the wound. Once the procedure has been completed and your wound is closed and dressed you’ll be sent home with clear instructions on how to look after it. You will also be told when and where to go to get the stitches taken out. We hope you found this Mohs surgery video useful and if you still have any further questions please contact the dermatology department that has arranged your surgery.
(This video is publicly and freely available on Youtube, and is inserted here for informative purposes on Mohs surgery. The speaker/s and the institutions on whose behalf they speak are represented by the videos. Skinmatters Mohs micrographic surgery was not involved in the making of the video, nor is represented by the speakers in any way)