Meet Mohs


Dermatologist Dr. Diane Trieu specializes in highly effective skin cancer surgery.

DrDianeTrieuSkin cancer is all too common. According to the Skin Cancer Foundation, one in five Americans will develop some type of skin cancer over their lifetime. Here in Louisiana, nearly 60 people are diagnosed with skin cancer every day.

Once diagnosed, skin cancer may require excision, or removal, of the cancerous tissue. Because of the margins needed to safely remove the cancer, excision often leaves scars or defects.

However, Mohs surgery, a procedure developed by Dr. Frederic E. Mohs in the late 1930s, reduces the amount of skin removed while ensuring a high cure rate. “Mohs is a tissue-sparing procedure,” says Dr. Diane Trieu, a dermatologist at Tulane Medical Center who specializes in Mohs surgery. “You can check 100 percent of the tissue margin for cancer, so you have a higher cure rate and a smaller scar.”

Here, Dr. Trieu takes us through the process of Mohs surgery, addressing common patient questions and concerns.

Types of Cancer and Areas Treated
Mohs surgery is often indicated for cancers of the face, neck and other highly visible areas, where a scar might be especially disruptive. It’s also appropriate for areas that heal more slowly, such as the legs.

Some skin cancers may be slower growing, or involve a lower risk; in these cases, a dermatologist may opt for standard excision. “Mohs is really indicated for high-risk skin cancer,” Dr. Trieu says. The two most common skin cancers treated with Mohs are basal-cell carcinomas and squamous-cell carcinomas.

“Melanoma is a little different,” Dr. Trieu says. “In New Orleans, off the top of my head, I don’t think anyone does melanomas with Mohs … I’m actually trying to bring that to Tulane.”

The Procedure
Mohs is performed as an outpatient procedure, with local anesthetic. It differs from standard excision in that the edges of the site are checked for cancer at the time of the procedure, instead of being sent away to a pathologist.

“What we do is circle the tumor and take small margins — one to two millimeters,” Dr. Trieu says. “We take frozen sections, and process the tissue right then and there. We can check 100 percent of the tissue margin, so we know if it’s positive for cancer.” If the surrounding margin tests positive for cancer cells, the excised area is slightly expanded to remove them. Then, the skin is closed with stitches, either in-office or by a cosmetic surgeon.

“It’s a bit longer of a procedure,” Dr. Trieu says. “It can be a few hours that you’re waiting. But after those few hours — once it’s all gone, it’s all gone.”

Post-Op Care
Keeping the surgical site clean and dry will help it heal. “Usually, it’s pretty simple,” Dr. Trieu says. “Before [patients] leave the office, we put a pressure bandage on for them.” The bandage stays on for one to two days, at which point patients can wash and dry the site with regular soap and water.

Patients should moisturize with plain petroleum jelly, like Vaseline, and keep the surgical site covered until the stitches are removed — generally within one to two weeks.

Diane Trieu, M.D.
Tulane University Medical Center
Department of Dermatology
1415 Tulane Ave.
(504) 988-1700

MEDICAL SCHOOL: Tulane University School of Medicine

RESIDENCY: Tulane University School of Medicine, Dermatology

FELLOWSHIP: Houston Methodist Hospital, procedural fellowship including Mohs surgery and cosmetic dermatology