By NEALE MULLIGAN
Researchers at the medical center have discovered a new application for a specialized procedure called Mohs micrographic surgery that could increase the cure rate of an invasive fungal disease.
The disease, known as cutaneous mucormycosis, primarily affects patients who are immunocompromised, particularly those who have diabetes, leukemia or who have undergone an organ transplant.
A paper recently published in Dermatologic Surgery described the novel application of Mohs surgery, considered the gold-standard for treating non-melanoma skin cancers. Mohs requires surgeons to painstakingly remove diseased tissue layer by layer, studying the pathology of each layer as they go in an effort to leave as much healthy tissue as possible intact.
The discovery could be significant for transplant patients susceptible to infection.
"Mucormycosis in immunocompromised patients is extremely serious and can be fatal," said Hayes Gladstone, MD, one of the study’s authors and director of Moh’s micrographic surgery and cutaneous laser surgery at the medical center.
Observed under a microscope, mucormycosis is a fungus with tree-like branches that jut out at 90-degree angles. These "branches" normally invade blood vessels, blocking off the blood supply, killing tissue and causing necrosis. The fungus can grow very quickly in a human being.
Gladstone treated a man who had undergone an organ transplant three years prior. The patient had developed a growth on one of his elbows. "He had pneumonia and was pharmacologically suppressed, so it kept growing," said Gladstone, assistant professor of dermatology.
"A biopsy was performed and it was mucormycosis. In many cases in the past, amputation may have been a reasonable option. But we could offer him this procedure and we were able to clear the fungus. After a year, there’s no recurrence."
While this procedure is most commonly used for treating skin cancers, Gladstone believes it’s a suitable technique for removing other types of tumors. Surgeons bevel the blade of a scalpel at a 45-degree angle or more, which is not normal for standard excisional surgery. This way, a surgeon gets more of a saucer-shaped specimen to see the "entire critical margin."
"We also draw on a special piece of paper the exact shape of the specimen, then we’ll look at it under the microscope," said Gladstone. "We can see exactly where the fungus is and then map it exactly on a precise drawing. That technique allows us to cut out the portion where there’s fungus as opposed to cutting out a wide excision. We can save skin rather than making a huge defect."
According to Gladstone, the technique in combination with the traditional use of the antifungal drug amphotericin potentially can spare some patients from more radical surgery such as amputation and decrease morbidity for the patient. "Ultimately, that leads to better patient care," he said.
While this is the first reported case of using Mohs micrographic surgery to treat mucormycosis, Gladstone and his colleagues reported that the techniques needs further study to create clinical guidelines.
Stanford researchers who contributed to the study include Landon Clark and R. Sonia Batra, MD.
Stanford Report, October 1, 2003