What is Synovial Sarcoma?
Synovial sarcoma is a type of soft tissue sarcoma. Soft tissue sarcomas are cancers of the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body, including synovial tissue. Synovial tissue lines the cavities of joints, such as the knee or elbow, tendons (tissues that connect muscle to bone), and bursae (fluid-filled, cushioning sacs in the spaces between tendons, ligaments, and bones). Although synovial sarcoma does not have a clearly defined cause, genetic factors are believed to influence the development of this disease.
How often does Synovial Sarcoma Occur?
Synovial sarcoma is rare. It accounts for between 5 and 10 percent of the approximately 10,000 new soft tissue sarcomas reported each year. Synovial sarcoma occurs mostly in young adults, with a median age of 26.5. Approximately 30 percent of patients with synovial sarcoma are younger than 20. This disease occurs more often in men than in women.
Where does Synovial Sarcoma Develop?
About 50 percent of synovial sarcomas develop in the legs, especially the knees. The second most common location is the arms. Less frequently, the disease develops in the trunk, head and neck region, or the abdomen). It is common for synovial cancer to recur (come back), usually within the first two years after treatment. Half of the cases of synovial sarcoma metastasize (spread to other areas of the body) to the lungs, lymph nodes, or bone marrow.
What are the Symptoms of Synovial Sarcoma?
Synovial sarcoma is a slow-growing tumor. Because it grows slowly, a person may not have or notice symptoms for some time, resulting in a delay in diagnosis. The most common symptoms of synovial sarcoma are swelling or a mass that may be tender or painful. The tumor may limit range of motion or press against nerves and cause numbness. The symptoms of synovial sarcoma can be mistaken for those of inflammation of the joints, the bursae, or synovial tissue. These noncancerous conditions are called arthritis, bursitis, and synovitis, respectively.
How is Synovial Sarcoma Diagnosed?
The doctor may use the following procedures and tests to diagnose synovial sarcoma:
- Biopsy: Tissue is removed for examination under a microscope.
- Immunohistochemical analysis: Tumor tissue is tested for certain antigen and antibody interactions common to synovial sarcoma.
- Ultrastructural findings: The tissue is examined using an ultramicroscope and electron microscope.
- Genetic testing: Tissue is tested for a specific chromosome abnormality common to synovial sarcoma.
How is Synovial Sarcoma Treated?
The type of treatment depends on the age of the patient, the location of the tumor, its size, its grade (how abnormal the cancer cells look under a microscope and how likely the tumor will quickly grow and spread), and the extent of the disease. The most common treatment is surgery to remove the entire tumor with negative margins (no cancer cells are found at the edge or border of the tissue removed during surgery). If the first surgery does not obtain negative tissue margins, a second surgery may be needed.
The patient may also receive radiation therapy before or after surgery to control the tumor or decrease the chance of recurrence (cancer coming back). The use of intraoperative radiation therapy (radiation aimed directly at the tumor during surgery) and brachytherapy (radioactive material sealed in needles, wires, seeds, or catheters, and placed directly into or near a tumor) are under study.
Patients may also receive chemotherapy alone or in combination with radiation therapy.