Fibrosarcoma

A fibrosarcoma is a cancerous tumor that can be found rarely in soft tissues and even more rarely in bone. As scientists have gained more understanding about soft tissue sarcomas, most tumors previously called fibrosarcoma have been recategorized under different names. What we now know as fibrosarcoma can occur in any of the connective tissues in the arms, legs, trunk, and pelvis.

Fibrosarcomas are very rare, representing just 3 percent of the 13,000 soft tissue sarcomas diagnosed in the U.S. each year. In adults, these tumors mainly affect people who are middle-aged or older. These cancers can act aggressively and metastasize (spread), mainly to the lungs and bones.

The Sarcoma Program at Penn Medicine’s Abramson Cancer Center is highly experienced in treating adults with fibrosarcoma. Our surgeons can often save arms and legs affected by tumors, as well as effectively operate elsewhere in the body. We also know when to consider additional therapy, with a full range of treatment options.

Because fibrosarcoma is rare, it can be challenging to distinguish from other tumors with similar features. Advances in sarcoma research and specialized testing now allow experienced sarcoma experts to identify fibrosarcoma more accurately and distinguish it from conditions like:

• Desmoid tumors
• Dermatofibrosarcoma protuberans
• Fibromyxoid sarcoma
• Malignant peripheral nerve sheath tumors (specifically, schwannomas)
• Osteosarcoma
• Sclerosing epithelioid fibrosarcoma
• Synovial sarcoma
• Undifferentiated pleomorphic sarcoma

Fibrosarcoma often doesn’t cause symptoms at first. Because these tumors usually develop deep within soft tissues, they may go unnoticed until they grow larger.

Possible signs and symptoms include:

• A lump or swelling that may or may not be painful
• Pain if the tumor presses on nearby nerves, muscles, or other tissues
• Tingling, numbness, or other unusual sensations in the affected area
• Reduced movement if the tumor affects a joint or nearby structures

It is currently unknown why most fibrosarcomas form. Several factors, however, can increase the risk of developing one of these tumors:

• Family genetics: Genetic changes inherited from parents sometimes cause syndromes that raise the risk for a range of health conditions. Fibrosarcoma risk is elevated in people with hereditary retinoblastoma and Li–Fraumeni syndrome (LFS).
• Other cancers: In unusual cases, another sarcoma called dermatofibrosarcoma protuberans (DFSP) can have areas of higher-grade fibrosarcoma within the tumor.
• Radiation therapy: An uncommon side effect of radiation therapy is the development of a fibrosarcoma years later.

Fibrosarcoma is rare, which makes an experienced care team especially important. At Penn Medicine, specialists in pathology, radiology, surgical oncology, orthopaedic oncology, medical oncology, and radiation oncology work together to evaluate each case and guide treatment decisions.

Our involvement in sarcoma research helps us advance the understanding and treatment of rare soft tissue sarcomas. Through clinical trials and ongoing collaboration with organizations like the Sarcoma Alliance for Research through Collaboration (SARC), we're helping improve care for people with fibrosarcoma and other rare soft tissue sarcomas.