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Mohs’ Micrographic Surgery – Information
Mohs’ micrographic surgery – a specialized technique for removing certain skin cancers such as basal cell carcinomas and squamous cell carcinomas.
In an outpatient operation (ambulatory surgery) with local anesthetic and a sedative for relaxation if necessary, the dermatologist removes one thin layer of the tumor at a time and examines each specially stained layer under the microscope. The surgery continues until the tissue sample shows a one- to two-millimeter margin of healthy tissue on all borders, ensuring that the dermatologist removes all of the malignancy. Because Mohs’ micrographic surgery is so precise it removes only the malignancy, sparing as much surrounding tissue as possible.
By comparison, conventional excision removes the tumor and what the surgeon believes is a reasonable amount of surrounding tissue to provide clean margins, which can result in removing considerably more tissue than just the malignancy. A pathologist later examines frozen sections of the tissue to confirm the margins. With conventional excision there is a change that the margins could be positive (contain cancer cells) and the surgeon would have to do another operation to remove more tissue.
Dermatologists use Mohs’ micrographic surgery when the skin cancer is on the face, nose, eyelids, or around the mouth, or if it is a larger, more aggressive cancer on the body. The procedure may take several hours altogether to complete, depending on how many layers of tissue the dermatologist must remove to get clean margins.
Many cancers removed using Mohs’ micrographic surgery heal with minimal scarring. The dermatologist performing the surgery usually repairs any residual defect as dermatologists also perform reconstructive surgery. Mohs’ micrographic surgery has an overall cure rate of 95 percent and up to 99 percent for certain kinds of malignant lesions, the highest for all current forms of treatment for these two types of skin cancer. Frederic E. Mohs, M.D. (1910–2002), discovered the technique while a medical student in the 1930s.
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