Synovial Tumors

Synovial tumors, also referred to as synovial cell sarcoma, are a rare type of soft tissue sarcoma that develops in the supporting tissue of the body such as muscle, fat, fibrous tissue, and blood vessels. Synovial sarcoma is named after the synovial tissue that lines the cavities of joints, such as the knee or elbow, tendons (tissues that connect muscle to bone), and bursae (fluid-filled, cushioning sacs inbetween tendons, ligaments, and bones), but it never originates in the joints themselves. When this disease metastasizes, approximately 50% will spread to the lungs, lymph nodes, or bone marrow.

The disease accounts for five to 10 percent of approximately 10,000 soft tissue sarcomas diagnosed each year. Synovial sarcoma occurs predominantly in young adults under 20 and this age group comprises 30% percent of synovial cases annually. Although synovial sarcoma does not have a clearly defined cause, genetic factors are believed to influence the development of the disease.

Many doctors have little experience with synovial tumors because they are so rare. Compounding the situation is the disease’s tendency to develop in areas that affect musculoskeletal systems. An orthopedic oncologist like Dr. Daniel C. Allison is best suited to diagnose and treat the condition. He leads a coordinated, multi-disciplinary team supported by the resources of a sophisticated medical center in Los Angeles.

Symptoms and Risk Factors

Synovial sarcoma is slow-growing and symptoms can be easily overlooked which delays diagnosis. About 50 percent of synovial sarcomas develop in the legs, especially the knees, followed by the arms as the next recurring location. The disease can also develop in the trunk, head and neck region, or abdomen, as well as recur within the first two years following the first treatment.

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.

Symptoms vary and depend on the original tumor’s location. Symptoms can include:

  • Altered voice
  • Difficulty swallowing and breathing
  • Severe pain if tumor adjacent to nerves

Synovial cell sarcoma usually occurs in young adults and is typically slow growing which can give the impression that it is harmless. While synovial cell sarcomas can be quite painful, a tumor can be symptom-free when it is deep-seated within the body.


The diagnosis starts with imaging studies. X-ray, sonogram, CT scan, and MRI may be used in the course of evaluating a suspicious mass.

The initial biopsy should be carefully planned by an experienced surgeon like Dr. Allison. He has the expertise to ensure that any tumor cells disturbed during the biopsy procedure are completely removed later during surgery to remove the entire mass.

Confirmation of a synovial cancer diagnosis prompts further imaging studies such as a PET scan of the whole body and/or CT scan of the chest, abdomen or pelvis. They are also used to evaluate the possibility of metastases.

Doctors use the material gathered during diagnosis to develop a patient’s treatment plan. During this process, they consider many factors that are specific to the patient, including:

  • Measure tumor size and spread
  • Confirm signs of metastasis
  • Verify if lymph nodes affected


The primary treatment for synovial sarcoma is surgery to remove the entire tumor with clear margins when possible. “Clear margins” are achieved when healthy tissue surrounding the tumor is removed along with the tumor, making it more likely that all cancer cells have been removed from the area. Depending on the location and size of the mass, it may be difficult for a surgeon to remove adequate margins around the tumor while preserving function. Radiotherapy may also be used, either before or after surgery, to reduce the risk of leaving cells behind.

When developing a treatment plan, an oncologist will consider the potential benefits of chemotherapy weighed against the possible negative effects of the treatment. A patient may wish to discuss these issues with the oncologist in order to better understand the treatment plan.

Participation in clinical trials is an important treatment option for many people with synovial sarcoma. Studies are in progress to determine the effectiveness of biological therapies (treatment to stimulate or restore the ability of the immune system to fight cancer), including monoclonal antibodies, and chemotherapy with hyperthermia (kills tumor cells by heating them to several degrees above body temperature).

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Contact the Orthopedic Oncology Specialist in Los Angeles

Dr. Daniel C. Allison has the specialized expertise of an orthopedic oncologist that is essential to diagnosis and treatment of synovial tumors. Dr. Allison is renowned for leading multi-disciplinary oncology teams supplemented with his extensive expertise in sarcoma diagnosis and treatment. He is the ideal physician to coordinate the type of integrated medical plan synovial tumors require. Call today to schedule a personal consultation at (310) 730-8008.


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