What is synovial sarcoma?
Synovial sarcoma is a malignant tumor of the soft tissues, usually around joints. Under the microscope the tumor resembles synovial tissue (the lining tissue of joints). Synovial tissue is found around the tendons (bands of fiber that connect muscle to bone), and can form bursa (fluid filled cushioning pouches or sacs found in spaces between tendons, ligaments and bones) found in the area of joints.
This condition tends to occur in adolescents and young adults and affects more males than females. The most common location of origin is the thigh near the knee, but synovial sarcoma can also occur near other joints, mainly in the arms and legs. Despite its name, it seldom arises within a joint.
Synovial sarcoma can spread (metastasize) to other areas of the body, particularly to involve regional lymph nodes. Metastasis to distant body tissues occurs in about half of all cases, usually months to years after the initial diagnosis is made, although they are at times present at diagnosis.
Synovial sarcoma is a rare tumor. It is one of many types of cancer classified as a soft tissue sarcoma, cancer that originates in soft tissue which includes fat, muscles, tendons, nerves, synovial tissue, blood vessels and other fibrous tissue. As a group, soft tissue sarcomas account for less than 1 percent of all new cancer cases each year. In the United States, approximately 900 children and adolescents are diagnosed with soft tissue sarcomas each year.
What causes synovial sarcoma?
The exact cause of synovial sarcoma is not entirely understood, however, studies have indicated that genetic alterations may play a role in the formation of soft tissue sarcomas. Researchers have studied a small number of families that contain several members of one generation who have developed soft tissue sarcomas. In addition, limited studies have shown a possible link between soft tissue sarcomas and the development of other types of cancer.
In synovial sarcoma, a rearrangement in the chromosome material between chromosomes X and #18 is usually present. This rearrangement changes the position and function of genes, causing a fusion of genes referred to as a "fusion transcript." Patients have an abnormal fusion transcript involving two genes which creates a novel (new) gene. This important discovery has led to improvements in diagnosing rhabdomyosarcoma, and may lead to newer treatments in the future.
Certain inherited diseases are also associated with an increased risk of developing soft tissue sarcomas. These include people with Li-Fraumeni syndrome (which involves alterations in the p53 gene) or neurofibromatosis (which involves alterations in the NF1 gene). For some soft tissue tumors, there seems to an association with an Epstein-Barr virus infection.
What are the symptoms of synovial sarcoma?
The following are the most common symptoms of synovial sarcoma. However, each child may experience symptoms differently. Symptoms can depend on the size and location of the tumor. Sometimes the symptoms of synovial sarcoma can resemble those of arthritis, bursitis or synovitis. Symptoms may include:
- Swelling or mass (usually deep-seated)
- Mass that may or may not be accompanied by pain
- Limping or difficulty using legs, arms, hands or feet.
The symptoms of synovial sarcoma may resemble other conditions. Always consult your child's physician for a diagnosis.
How is synovial sarcoma diagnosed?
In addition to a complete medical history and physical examination, the most conclusive diagnostic procedure for synovial sarcomas is a biopsy, a single tissue sample taken from the tumor through a simple surgical procedure. The tumor's cellular appearance under a microscope enables doctors to distinguish it from other types of cancer.
Your child will likely undergo various imaging studies that will include one or more of the following:
- X-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film X-rays are very useful in the diagnosis of soft tissue tumors and frequently they allow the physician to distinguish benign from malignant tumors. An x-ray is often the first diagnostic study, and often gives the doctor information regarding the need for further testing.
- Magnetic Resonance Imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body. Thus test is used to assess the size and extent of the mass and its relationship to surrounding muscle, bone, nerves and blood vessels.
- Computerized Tomography scan (also called CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices)both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed that general x-rays. They are used primarily to asess the chest and lung for metastatic tumors
- Bone scans - a nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation.
Other tests include:
- Complete blood count (CBC) - a measurement of size, number and maturity of different blood cells in a specific volume of blood
- Blood tests - (including blood chemistries)
Once synovial sarcoma has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and gives some indication of prognosis for the condition.
A synovial sarcoma may be localized, meaning it has not spread beyond the joint where it arose or beyond nearby tissues, or metastatic, meaning it has spread to lungs, bones other than the bone that the tumor originated in, or to other organs or structures of the body.
Children with synovial sarcoma are treated through the Bone and Soft Tissue Program at Dana-Farber/Boston Children's Cancer and Blood Disorders Center, an integrated pediatric hematology and oncology partnership between Dana-Farber Cancer Institute and Boston Children’s Hospital. We utilize the expertise of both Boston Children's Hospital, consistently ranked one of the top children's hospital in the country, and Dana-Farber Cancer Institute, a nationally recognized leader in cancer care and a member of the Dana-Farber/Harvard Cancer Center. Through our multidisciplinary approach, we provide in-depth discussion of each case and personalized treatment plans for every patient.
Specific treatment for synovial sarcoma will be determined by your child's treatment team based on:
- Your child's age, overall health, and medical history
- Extent and location of the disease
- Your child's tolerance for specific medications, procedures or therapies
- How your child's doctor expects the disease may progress
- Your opinion and preference
Surgery includes biopsy and surgical removal of the entire tumors, nearby muscle and lymph nodes. Depending on the location and size of the tumor, it may be necessary to remove all or part of the limb. In most cases limb-sparing surgery is used to avoid amputation. The following is a description of both procedures:
- Limb-salvage surgery - Limb-sparing surgery is indicated only if your child's orthopedic surgeon determines that it is possible that the tumor, and wide margins of healthy tissue surrounding the tumor, can be removed. Through limb-sparing surgery, all of the tissue involved with the tumor, including some degree of muscle surrounding it and nearby lymph nodes, are removed; unaffected tendons, nerves and vessels are saved.
If bone is also removed, it is usually replaced with a bone graft or with a metal rod. Subsequent surgery may be needed to repair or replace rods, which can become loose or break.
Patients who have undergone limb-sparing surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery.
Some patients who have had limb sparing procedures may eventually have to undergo amputation. Radiation therapy and/or chemotherapy are given either before surgery to shrink the tumor, or after surgery to kill remaining cancer cells.
- Amputation - In certain cases, if your child's orthopedic surgeon determines that the tumor cannot be removed because, for example, it involves the nerves and blood vessels, amputation is the only option.
During the operation, doctors ensure that muscles and skin form a cuff around the amputated bone. A cast is applied in the operating room which permits a temporary artificial leg (prosthesis) to be applied during the first few post-operative days for walking. Crutches are used for several weeks. As the swelling decreases (10 to 14 days) the patient is fitted for a plastic, temporary socket and prosthesis, which is used for 3 to 4 months until the stump is healed sufficiently to accept a permanent artificial leg.
The advantages of an amputation are that it is a simple operation with minimal chances of surgical complication and it definitively removes the local tumor. The functional outcome is good with the modern prostheses available today and with "immediate-fit" prostheses applied in the operating room.
Although the patient will probably have a limp with above-the-knee amputations, the procedure is functional and stable. He/she will be able to walk, climb stairs, swim (with the prosthesis on or off) and participate in many sports such as skiing, basketball, baseball, and tennis although running will be limited. The functional limitations are left to the imagination and determination of the patient.
Radiation therapy is a treatment that uses high energy rays from a specialized machine to damage or kill cancer cells and shrink tumors. This is sometimes used in conjunction with surgery for synovial sarcoma, either before or after resection of the tumor. On rare occasions radiation alone is used for treatment of the primary tumor.
Chemotherapy is a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Chemotherapy may be used alone for some types of cancer or in conjunction with other therapy such as radiation or surgery. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat.
While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare and, in some cases, prevent these symtpoms from occurring, if possible. Chemotherapy is a systemic treatment, meaning it is introduced into the bloodstream and travels throughout the body to kill cancer cells.
Chemotherapy may be given:
- As a pill to swallow
- As an injection into the muscle or fat tissue
- Intravenously (directly to the bloodstream; also called IV)
- Intrathecally (given directly into the spinal column with a needle
Supportive care refers to any type of treatment to prevent and treat infections, side effects of treatments and complications and to keep your child comfortable during treatment.
Continuous Follow-Up Care
A schedule of follow-up care will be determined by your child's physician and other members of you care team to monitor ongoing response to treatment and possible late effects of treatment. Treatment options will vary greatly, depending on your child's individual situation. Your child's physician and other members of your care team will discuss these with you in-depth.
What is the long-term outlook for patients with synovial sarcoma?
Prognosis greatly depends on:
- The extent of the disease
- The size and location of the tumor
- A presence of absence of metastasis
- The tumor's response to therapy
- The age and overall health of your child
- Your child's tolerance of specific medications, procedures, or therapies
- New developments in treatment
As with any cancer, prognosis and long-term survival can vary greatly from individual to individual. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with synovial sarcoma. Side effects of radiation and chemotherapy, as well as recurrence of the disease, can occur in survivors of synovial sarcoma.
What is the latest research on soft tissue sarcomas?
Researchers at Dana-Farber/Boston Children's are conducting numerous research studies that will help clinicians better understand and treat soft tissue sarcomas.
Other types of treatment currently being studied include:
- Angiogenesis inhibitors - substances that may be able to prevent the growth of tumors by blocking the formation of new blood vessels that feed the tumors.
- Biological therapies - a wide range of substances that may be able to involve the body's own immune system to fight cancer or lessen harmful side effects of some treatments
- Neoadjuvant chemotherapy and radiotherapy - combining radiation and chemotherapy may reduce the incidence of metastatic disease in synovial sarcoma. Treatments using chemotherapy and radiotherapy before resecting the primary tumor in synovial sarcoma in adults and children are being investigated.
Learn more about the Bone and Soft Tissue Program.
Learn more about our solid tumor research and clinical trials.