Dermatology and Skin Cancer Specialists

American Society for
Mohs Surgery

Lindall Perry, MD
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Contact Columbia Dermetology

573-876-1616

573-876-1678 fax

401 Keene St.
Columbia, Missouri 65201
(inside the Boone Clinic Bldg.)

Mohs Skin Cancer Surgery

The following information has been taken from the pamphlet, "Important Patient Information Regarding Mohs Micrographic Surgery in the Treatment of Skin Cancer", provided by the American Society for Mohs Surgery.

What is Mohs Micrographic Surgery?

Mohs micrographic surgery is a specialized, highly effective technique for the removal of skin cancer. The procedure was developed in the 1930s by Dr. Frederic Mohs at the University of Wisconsin and is now practiced throughout the world. Mohs surgery differs from other skin cancer treatments in that it permits the immediate and complete microscopic examination of the removed cancerous tissue, so that all “roots” and extensions of the cancer can be eliminated. Due to the methodical manner in which tissue is removed and examined, Mohs surgery has been recognized as the skin cancer treatment with the highest reported cure rate.

The Mohs Surgical Procedure

Typically, Mohs surgery is performed as an outpatient procedure in the physician’s office. Although the patient is awake during the entire procedure, discomfort is usually minimal and no greater than it would be for more routine skin cancer surgeries. The Mohs surgical procedure is illustrated in the following diagrams:

Stage 1

Mohs Surgery Stage 1

Figure A

The area to be treated is cleansed, marked, and injected with a local anesthetic. The Mohs surgeon removes the visible cancer, along with a thin layer of additional tissue (Stage 1). This procedure takes only a few minutes, and the patient waits while tissue is being processed and examined.

Figure B

The removed tissue specimen is cut into sections, stained, and marked on a detailed diagram (Mohs map).
Mohs Surgery Stage 1 - Figure B

Figure C

Tissue is frozen on a cryostat, and technician removes very thin slices from the entire edge and undersurface. These slices are then placed on slides and stained for examination under the microsope. (This is the most time-consuming portion of the procedure, often requiring one hour or more to complete.)
Mohs Surgery Stage 1 - Figure C

Stage 2

Figure D

The Mohs surgeion carefully examines the entire undersurface and complete edge of the specimen, and all microscopic "roots" of the cancer are precisely identified and pinpointed on the Mohs map. Upon microscopic examination, if residual cancer is found, the Mohs surgeion utilizes the Mohs map to direct the removal of additional tissue (Stage II). Note that additional tissue is removed only where cancer is present.
Mohs Surgery Stage 2

Stage 3

Figure E

This process is repeated as many times as necessary to locate any remaining cancerous areas within the tissue specimen (Stage III, Stage IV, etc.)
Mohs Surgery Stage 3

Stage 4

Figure F

When microscopic examination reveals that there is no remaining tumor, the surgical defect is ready for repair.
Mohs Surgery Stage 4

More about Mohs

Click on a topic to learn more.

Special Qualifications of the Mohs Surgeon
Advantages of the Mohs Surgical Procedure
Special Indications for Mohs Surgery
Insurance Coverage for Mohs Surgery
Patient Preparation for Surgery
Duration of Procedure
Minor Post-Surgical Discomfort Expected
Options for Post-Surgical Reconstruction
Wound Healing, Scarring, and Scar Revision
Potential Complications Associated With Mohs Surgery
About the American Society for Mohs Surgery