Fibrosarcoma Health Article

Definition

Fibrosarcoma is a malignant tumor that arises from fibroblasts (cells that produce connective tissue). This is a type of sarcoma that is predominantly found in the area around bones or in soft tissue.

Description

Fibrosarcomas are the result of fibroblasts, which produce connective tissue such as collagen. Fibrosarcoma tumors are consequently rich in collagen fibers. The immature, proliferating fibroblasts take on an interlacing, or herringbone, pattern.

Fibrosarcomas can form from fibroblasts in soft tissue such as muscles, connective tissues, blood vessels, joints, and fat. Soft tissue fibrosarcoma normally occurs in fibrous tissue of the body's trunk and the extremities such as the arms and legs. Soft tissue fibrosarcomas are extremely rare, with approximately 500 new cases reported each year.

Sarcomas of the bone

Fibrosarcoma can also occur in bones. While a bone is made up of inorganic molecules such as calcium phosphate, it also has an organic element made up of 95% collagen, similar to the collagen found in the skin. Fibrosarcomas of the bone usually occur in long bones in the bone marrow cavity where collagen is formed. The bones that predominantly yield fibrosarcomas are those in the legs, arms, pelvis, and hip.

Sarcomas of the bone are rare and represent about 0.2 percent of all new cancer cases each year. The two most common forms of bone cancer are osteosarcoma and Ewing's sarcoma. Among the less common are chondrosarcoma, fibrosarcoma, and malignant fibrous histiocytoma, all of which arise from spindle cell neoplasms.

Demographics

Fibrosarcomas typically develop in people between the ages of 25-79. The peak age of occurrence is 55-69 years. Generally, fibrosarcomas develop equally in men and women, though they are rare in children.

Infantile fibrosarcoma, also known as congenital fibrosarcoma or juvenile fibrosarcoma, is unique. Under microscopic examination, it is similar to fibrosarcomas seen in adults. However, infantile fibrosarcomas have a more positive prognosis with a post-treatment, five-year survival rate of 83% to 94%.

Causes and symptoms

Fibrosarcomas of the bone are sometimes connected with underlying benign bone tumors. Both fibrosarcomas of soft tissue and of the bone can develop as a result of exposure to radiation. This can result as a side effect from previous radiation therapy for unrelated primary cancer treatment. Individuals with other bone diseases, such as Paget's disease and osteomyelitis, are at a higher risk for developing fibrosarcomas.

There are many symptoms associated with the onset of fibrosarcomas. The following is a list of the main symptoms that may be present:

• pain
• swelling
• firm lump just under the skin or on a bone
• broken bone
• impeded normal range of motion
• neurologic symptoms
• gastrointestinal bleeding (seen in soft tissue abdominal fibrosarcomas)
• urinary frequency (seen in pelvic fibrosarcomas)
• urinary obstruction (seen in pelvic fibrosarcomas)

Diagnosis

In order to diagnose fibrosarcoma, a doctor will take the patient's medical history and will conduct a thorough physical exam. Blood tests will be performed to rule out other conditions and to identify cancer markers.

The most revealing initial exam is an x ray. It can show the location, size, and shape of the tumor. If a malignant tumor is present, the x ray will expose a soft tissue mass with ill-defined edges. This procedure takes less than an hour and can be performed in the doctor's office.

Once there is evidence of a tumor, one or more of several other procedures may be performed, including computed tomography (CT) scans, magnetic resonance imaging (MRI), angiograms, and biopsies.

Treatment team

The patient's primary care physician may perform the initial diagnostic tests. However, in order to comprehensively diagnose and treat fibrosarcomas, the primary care physician will refer the patient to an oncologist (cancer specialist). Radiologists, pathologists, and surgeons will also be involved to read x rays, examine tissue samples, and, if needed, remove the tumor.

Other individuals might be involved with the treatment of fibrosarcoma, including nurses, dieticians, and physical or vocational therapists.