Detect, manage rare malignant condition

Chicago - Surgical management of dermatofibroma sarcoma protuberans (DFSP) has superior outcomes with Mohs micrographic surgery over traditional excision, according to Hayes Gladstone, M.D., director of the division of dermatologic surgery, Stanford University, Stanford, Calif.

Speaking about his presentation at the American Academy of Dermatology Academy '05, Dr. Gladstone tells Dermatology Times that DFSP are often confused with dermatofibromas because they are similar in appearance.

Appearance, location

Anatomically, about 50 percent to 60 percent of instances occur on the trunk of the body, 25 percent on the upper limbs and 10 percent to 15 percent on the head and neck. They usually do not cause pain, and there may be periods of dormancy and acceleration in their growth, Dr. Gladstone explains.

DFSP, which start as a flat or depressed plaque, can occur as a result of a trauma such as a surgery or a burn, where they would appear very similar to a dermatofibroma, Dr. Gladstone says.

"A trauma makes it even more difficult for the dermatologist to differentiate between a dermatofibroma sarcoma and a dermatofibroma," Dr. Gladstone says.

Rare incidence

The incidence of DFSP is very rare at five in 1,000,000. They represent 1 percent of all soft tissue sarcomas and 0.1 percent of all malignancies. They typically present between the ages of 20 and 50 and occur to a slightly greater degree in males than in females. There are three histologic variants including myxoid, Bednar and fibrosarcomatous. The Bednar variant occurs more often in African-Americans.

To make a definitive diagnosis, a physician should obtain a biopsy. If Hematoxylin and Eosin (H&E) examination does not definitively demonstrate a diagnosis, then CD34 stains will help to differentiate DFSP from a dermatofibroma.

DFSP are malignant, but rarely metastasize, and can be excised surgically. When they do metastasize, it is because they have recurred several times, Dr. Gladstone says.

Management options: Mohs is best

Wide-excision surgery, the traditional management option, has shown there to be recurrence rates of up to 40 percent, which makes Mohs surgery a preferred option, according to Dr. Gladstone.

A retrospective study published in the European Journal of Surgical Oncology in 2004 put recurrence rates at between 10 percent and 60 percent using traditional excision of DFSP. Patients in the study were followed for about five years, and the mean time to recurrence was just over three years.

By contrast, a study published in Cancer in July of 2002 looked at 29 cases, 21 of which were primary malignancies and eight of which were recurrent malignancies, where Mohs micrographic surgery was employed and found a 100 percent five-year success rate.

A literature review, looking at cases where Mohs micrographic surgery was performed, showed cure rates of 90 percent and greater with no regional or distant metastasis.

"There is a general feeling amongst surgeons and oncologists that dermatofibroma sarcomas can be managed through wide excision surgery, despite the data indicating that Mohs is producing better outcomes," Dr. Gladstone says, noting Mohs surgery examines the entire critical margin. "I think they need to be educated more to the value of Mohs surgery."

Experimental treatments

Experimental treatments, such as the use of biological compounds, which target particular molecules, can reduce the size of uncommonly large tumors so they can then be excised - pointing to a new opportunity in treatment, particularly of large lesions.