Mohs Micrographic Surgery

Last Modified: May 6, 2007

Dear OncoLink "Ask The Experts,"

My father-in-law was recently diagnosed with melanoma of the eyelid. Could you please tell me how this is treated? Is it possible to remove one's eyelid?

Christopher J. Miller, MD, Assistant Professor of Dermatology at the Abramson Cancer Center of the University of Pennsylvania, responds:

The primary treatment for melanoma is excision. The recommended margins for excision are based on the depth of the melanoma measured under the microscope. For a melanoma in situ (just involving the epidermis/top layer of the skin), the recommended margin is 0.5 cm of normal appearing skin around the clinically visible tumor. For a melanoma <1 mm in depth, the recommended margin is 1 cm. For a melanoma 1-2 mm in depth, the recommended margin is 1-2 cm. For a melanoma >2 mm in depth, the recommended margin is 2 cm.

These margins are not set in stone. Frequently in areas as critical as the eyelid, we will cheat on the margins. In cases like this, Mohs micrographic surgery can be extremely helpful to be sure the cancer is all out and still spare critical normal tissue.

Mohs surgery uses a microscope to assure removal of the entire tumor. See the diagram below that demonstrates the procedure. The dermatologist acts as surgeon, pathologist and plastic surgeon in this procedure. The use of the microscope during the procedure provides an extremely precise method for removing cancerous tissue; at the same time, sparing the greatest amount of healthy tissue. For this reason, Mohs surgery may result in smaller surgical defects and less noticeable scarring, as compared to other surgical methods to remove skin cancer. The Mohs procedure is recommended for skin cancer removal in areas where maximum preservation of healthy tissue is desirable for cosmetic and functional purposes. It may also be indicated for lesions that have recurred following prior treatment, or for lesions with the greatest likelihood of recurrence.

Whether or not the melanoma will require a full thickness excision of the eyelid will depend on its location. If it is located at the lid margin (in the eyelashes), that may be necessary. It may not be necessary if it does not involve the lid margin. Reconstruction of the eyelid can be done. Of course, it is more difficult for larger full-thickness excisions. The final defect will depend almost entirely on the exact location and the degree of risk (mainly a function of depth) associated with the melanoma.