Dermatofibrosarcoma protuberans

A dermatofibrosarcoma protuberans (DFSP) is a rare type of tumor called a soft tissue sarcoma that grows just beneath the skin. It involves the middle layer of the skin (the dermis) and fat or other tissues. In longstanding cases, it may also extend into muscle and fascia, the tissue that surrounds and supports structures, including muscles, organs, and blood vessels.

Most dermatofibrosarcoma protuberans are found on the chest, belly, pelvis, or back. Other common locations include the arms, legs, head, and neck. These tumors tend to affect people in their 30s, 40s, and 50s. While DFSP may return after treatment, it rarely spreads.

Penn Medicine’s Abramson Cancer Center is home to sarcoma specialists who are among the nation’s most experienced DFSP experts. They work with our orthopaedic oncology and dermatology care teams to provide a full range of expertise, including surgeons who focus on certain areas of the body. Once you’ve been diagnosed with DFSP, we’ll continue monitoring you for skin changes so we can start further treatment right away if the cancer returns. From diagnosis to treatment and beyond, we provide expert care to manage this rare condition.

Doctors divide dermatofibrosarcoma protuberans into several types, based on the cells they contain and other features:

• Conventional DFSP: Most DFSP cases are this type. Fewer than 5 percent of these tumors spread, and they do so only after cancer has returned several times after treatment.
• Fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP): Parts of these cancers look and act more like fibrosarcoma. They’re likely to return and spread.
• Giant cell fibroblastoma: These tumors feature much larger cells. They’re also called juvenile dermatofibrosarcoma protuberans because they affect children and teens most often.
• Myxoid dermatofibrosarcoma: These tumors feature an unusual tissue called myxoid stroma.
• Pigmented dermatofibrosarcoma protuberans: These cancers, also called Bednar tumors, feature dark-colored cells. They occur most frequently in the Black population.

Early DFSP may look like a bruise or birthmark, but as the tumor grows, it can form lumps. The progression of symptoms may include the following:

• A firm area forms just beneath the skin, which may cause the surrounding skin and tissues to turn reddish brown.
• DFSP grows slowly but steadily, with several pimple-like bumps appearing, colored either reddish brown or violet.
• Tumors can eventually reach up to one or two inches across.
• Sometimes a painful, open wound forms.

DFSP forms because of a genetic change involving chromosomes, the structures in cells made of DNA. A gene on chromosome 17 changes places with a gene on chromosome 22. Researchers don’t yet understand why this gene change happens with DFSP. This genetic change is not inherited and cannot be passed down to children.

Genetic changes that can be caused by exposure to certain chemicals, previous medical treatments, or unusual genetics inherited from a parent are found in other soft tissue sarcomas. It’s still unclear if any of these risk factors apply to DFSP.

There is some evidence that a previous skin injury could raise the risk of developing DFSP. Some of these tumors develop in places on the skin with scars or tattoos. Researchers are actively studying this possible link.

At Penn Medicine, our doctors have specific training and experience in this rare cancer. A team of providers with expertise in sarcoma, orthopaedic oncology, dermatology, pathology, and other specialties can give you an accurate DFSP diagnosis and create an individualized treatment plan for you. Our experts serve on a tumor board that discusses sarcoma cases, allowing specialists from a variety of disciplines to provide input and help guide your care. And because we have a history of sarcoma research, we can offer the latest advancements in treatment, ensuring you receive the most advanced care.