Mohs Micrographic Surgery

“I was very happy with treatment and results of Mohs and Dr. Coven – great personality – ‘I love him’ and I am very glad I came here.” – Dan B.

“During a recent scheduled visit to Dr. Basuk’s office, I met Dr. Coven, who performed the Mohs precedure, and Dr. Hassan, the plastic surgeon who finished up. Both doctors and staff were professional, efficient and most kind. I was impressed with how smoothly everything went and how it was performed in a painless and timely manner. I would recommend Dr. Basuk’s office as the “Premier Office” for the treatment of skin disorders.” (patient testimonial)

“I had the Mohs procedure from Dr. Coven and the result has been excellent. The cancer is gone and the scar is hardly noticable. I am very grateful for his skillful work.” – R.G., Sayville

Mohs Micrographic Surgery was pioneered in the 1930’s by Frederick Mohs, M.D., at the University of Wisconsin to remove complicated skin cancers.  Like our Dr. Coven, many of today’s Mohs surgeons are trained during a special fellowship to perform surgery and the related pathology, though some have no formal training.  Mohs surgeons work with a certified histotechnologist who processes the tissue specimens.

While several effective methods are available for the treatment of skin cancer, the treatment choice is dependent on several factors including size, treatment location, and tumor type.  Mohs Surgery is indicated for basal and squamous cell skin cancers and provides the highest cure rate for both primary (first time) cancers and recurrent cancers (those cancers that reappear). Mohs surgery can be performed anywhere on the skin, but is especially important for facial cancers, large or aggressive tumors, or cancers located in areas with high risk of reccurrence (e.g. near the eyes, nose or ears).

When a skin cancer is removed, it is important to remove all the cancer cells. Because cancer cells microscopically infiltrate the nearby skin, normal skin near the cancer must be removed, too. The amount of normal-looking skin that must be removed is a balance between the attempt to eradicate the cancer and the desire to keep as much healthy skin as possible. This “cancer/not cancer” region is called the “margin”. Mohs developed his technique to minimize the margin taken from the patient, while increasing reliability that the entire cancer is removed.

How is this done? A very small margin around the obvious cancer is taken, then processed and evaluated in a Mohs lab using stains and a microscope. Because the stains used show the cancerous tissue clearly, the edge of the cancerous growth can be identified easily, and the surgeon can see if and where the next excision should be done. In this way, the Mohs surgeon hunts down the cancer as it is found to have progressed into the normal-looking skin, and eliminates it. All cancer surgery is meant to remove all of the cancerous growth: Mohs’ technique allows the surgeon to remove a minimal amount of normal skin while doing so.

Microscope view of stained skin.  Cancerous tissue shows as dark ovals.

Mohs Surgery is a complex procedure combining surgical excision with immediate microscopic examination of the entire tissue specimen.  This is done in five steps:

1. Numbing the skin with a local anesthetic.
2. Surgical removal of a thin, bowl shaped layer of skin containing the tumor.
3. Dividing the specimen into slices that are numbered, mapped, color coded, sectioned, and stained using dedicated, specialized equipment for this task. [Our office is fully equipped for Mohs surgery.]
4. Examination by the Mohs Surgeon of each section under a microscope to determine if the entire tumor has been removed.
5. If there is any remaining tumor, the above steps 1-4 are repeated until the entire tumor is removed.  Once it has been determined that the tumor has been removed completely, the skin defect may be repaired.

The Mohs Surgery technique allows examination of the entire surgical margin (the edge of the skin removed in each step) and, if tumor is still present, pinpoints the precise location of the leftover cancer.  Thus, the Mohs surgeon can selectively remove another layer of skin from only the area where the cancer is remaining to minimize the amount of normal skin removed. Until the preceding stage is examined, the surgeon doesn’t know whether another stage is necessary. Because some skin cancers are complicated, multiple stages of removal may be necessary.

Cryostat used in our office to prepare tissue for staining and subsequent microscopic examination.