Synovial Sarcoma

What is Synovial Sarcoma?

Synovial sarcoma, which is also known as malignant synovioma, is a soft-tissue sarcoma that affects the joints of the arms, neck or legs. It is a rare form of cancer affecting about 1 to 3 individuals for every one million in the population. Synovial sarcoma usually affects teenagers and young adults and is most prevalent among males than females.

Synovial sarcoma was thought to affect the synovium, which is the soft tissue found between the joints. However, it was soon discovered that the cells from which the sarcoma develops are not really related to the synovial tissues. The legs, particularly the knees are usually the most affected part followed by the arms. Less common locations for synovial sarcoma include the head, trunk, neck and the abdomen but there have also been cases in which the prostate, brain and heart have also been affected.

What Causes Synovial Sarcoma?

The causes for synovial sarcoma are not yet known but it has been linked with chromosomal translocation. This means that there has been an interchange between the SS18 gene on chromosome 18 and any of the 3 SSX genes on chromosome X. This fusion would bring about a mutant gene that is necessary for the development of the disease.

Signs and Symptoms

Synovial sarcoma may be asymptomatic during the initial stages of tumor growth which may lead to the delay in diagnosis and treatment of the tumor.

Signs and symptoms of synovial sarcoma may be dependent on the tumor location but generally include the following:

  • A mass that may be swollen, tender or painful.
  • Limited range of movement because of the tumor.
  • Numbness and pressure because of the tumor pressing on the nerves.
  • Difficulty in swallowing or breathing if the sarcoma is in the head or neck region.
  • Possible alteration of the voice.
  • Fatigue.

However, it may also be possible that a painless mass may develop or that the signs and symptoms of sarcoma may be mistaken as arthritis, bursitis or synovitis.

Diagnosis and Radiology

  • Synovial sarcoma may be diagnosed through various imaging studies like radiographic examination, ultrasound, computed tomography (CT scan) and magnetic resonance imaging (MRI). These imaging studies would be helpful in determining the size and location of the tumor.
  • Biopsy of the tumor is the next step and is necessary to further analyze the sarcoma. A small tissue sample is extracted either by open biopsy or core needle biopsy. Open biopsy would require the creation of a small surgical incision to remove a tissue sample while core needle biopsy would make use of a large bore needle to extract the sample.
  • Immunohistochemical analysis would also be utilized to ascertain the presence of certain antigen and antibody found in synovial sarcoma.
  • Genetic testing would test for abnormality in a specific chromosome common among synovial sarcoma.
  • Positive emission test scan of the whole body or computed tomography of certain body parts may need to be done once malignancy of the tumor has been established. This is done to detect metastasis in various body parts like the abdomen, chest and pelvis.

Important factors that need to be considered when establishing the diagnosis include the following:

  • The size of the tumor and how invasive it is.
  • Possible metastasis of the tumor to various body organs.
  • Possible involvement of the lymph nodes.

Treatment for Synovial Sarcoma

Similar to other forms of malignancies, the primary modes of treatment for synovial sarcoma include surgery, chemotherapy and radiation therapy.

  • Surgery is the primary treatment indicated for synovial sarcoma to remove the tumor with clear margins as much as possible. A safety margin of healthy tissue is also removed to ensure that all cancer cells in the surrounding area are also removed. Surgery has a 20-70 percent chance of treating the condition.
  • Conventional chemotherapy utilizes chemotherapeutic drugs in treating synovial sarcoma especially in cases with advanced metastasis. These drugs, which would include doxorubicin hydrochloride and ifosfamide, eradicate the tumor by reducing the number of microscopic cancer cells. However, it is not yet well established how effective chemotherapy is with synovial sarcoma although treatment with doxorubicin and ifosfamide has been shown to marginally improve some cases.
  • Radiation therapy is another treatment option used to eradicate cancerous cells. This may be done prior or after the surgical removal of the tumor. However, like chemotherapy, the mechanism and benefits of radiotherapy is also still underway.

A patient should carefully discuss the treatment options, advantages and disadvantages of each treatment modality with the oncologist. Two option modalities may be necessary to fully eradiate the cancer cells. It is therefore best that a patient would discuss every possible issue or question in order to better understand the chosen treatment plan.

Prognosis and Recurrence

The prognosis for synovial sarcoma is dependent on a variety of factors including the tumor size, invasiveness, metastasis and involvement of the lymph nodes. Patients who are diagnosed early and with small tumors usually have a good prognosis. However, patients who have tumors greater than 5 cm have a greater risk for developing metastasis. Unfortunately, those who have profound or established metastasis, especially into the lungs, have a poor prognosis.

Synovial Sarcoma has the tendency to recur especially within the first two years after the initial treatment was undertaken. Half of these usually metastasize to other body parts like the lungs, bone marrow and the lymph nodes.

It is therefore important to have a physical check-up once abnormal masses may be noted to ensure early treatment and diagnosis of the disease. Early diagnosis and treatment would give the patient a better prognosis. Although rare, synovial sarcoma is a serious condition that needs prompt treatment. This can only be done with an early referral to an oncologist as soon as signs and symptoms may be noted. Each day wasted to delay treatment could be another day given to increase chances for metastasis. Synovial sarcoma should therefore be treated at the earliest possible time.


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