What Is Synovial Sarcoma?

Medically Reviewed by Jennifer Robinson, MD on September 17, 2019

Synovial sarcoma (SS) is a rare type of cancer. It affects soft tissues, which connect, support, and surround bones and organs in your body. These may include muscle, fat, blood or lymph vessels, nerves, tendons, and the lining of your joints.

Very few people get this disease. It accounts for less than 1% of all cancers. Doctors usually find it in teens and young adults (ages 15 to 35).

If you or someone you love has it, there are treatments and clinical trials that you can choose with your doctor.

Synovial Sarcoma, Defined

The word “synovial” comes from the name of the lining of the joints. In most cases, the joints themselves aren’t affected by the cancer. Synovial sarcoma can affect not only the synovium but also other soft tissues that surround a joint.

“Sarcoma” is a tumor made up of cancer cells in the bone and soft tissue.


Doctors don’t know what causes synovial sarcomas. But they do know about things that may make a person more likely to get it. For instance, it may be more likely if certain rare diseases run in your family.

You may also be more likely to get a synovial sarcoma if you’ve:

  • Been exposed to certain chemicals (such as thorium dioxide, vinyl chloride, or arsenic)
  • Been treated with radiation
  • Had long-term swelling in the arms or legs

Synovial sarcomas are made up of cells with genes that have errors (mutations) in them. These gene glitches don’t get passed down through families. Instead, they form over time for unknown reasons. The gene errors for synovial sarcomas often happen when certain chromosomes break and the pieces latch onto other chromosomes.


You may not have any signs or symptoms early on. But as these tumors grow, you may get a lump or swollen spot.

The most common places for synovial sarcomas are the soft tissues around your hip, knee, ankle, or shoulder joints. For some people, these tumors grow large enough to make it harder to move, or they press nerves and cause numbness or pain. In rare cases, they can happen in the head, neck, or chest.


Your doctor will give you tests to see what the lump, pain, or swollen spot you have is. You may get:

  • Imaging tests such as an X-ray, CT scan, and MRI scan
  • Genetic tests to look for the DNA errors that are seen in most SS tumors
  • Biopsies: Surgery to remove all or some of the tumor for lab testing


The type of treatment you doctor recommends depends on:

  • The size, grade, and stage of your tumor
  • Where your tumor is
  • If the tumor has spread
  • Your age and overall health

The first step is often surgery to remove the tumor. After that, most people get chemotherapy and radiation. In some cases, you may get chemo or radiation before surgery to shrink the tumor.

After treatment, it’s important to keep up with all your doctor visits to make sure the synovial sarcoma doesn’t come back. If the tumor comes back, it may grow to a size that your doctor can see on a scan. Some tumors come back and spread to other parts of the body.

Clinical Trials

Researchers are working to develop new treatments for synovial sarcomas. Some are in clinical trials now. These methods may target the tumor cells more directly or help your immune system fight the cancer.

You may want to ask your doctor if there’s a clinical trial that would be a good fit for you. Scientists use them to see if new treatments are safe and how well they work. Clinical trials can be a way for people to try new medicine that isn't available to everyone. Your doctor can help you look for a trial that might be a good fit for you and let you know what’s involved and how to enroll.

WebMD Medical Reference


SOURCES:, The Liddy Shriver Sarcoma Initiative: “Overview -- What is Synovial Sarcoma?”

National Center for Advancing Translation Sciences, Genetic and Rare Disease Information Center: “Soft Tissue Sarcoma,” “Synovial Sarcoma.”

American Cancer Society: “What is a soft tissue sarcoma?”, The Liddy Shriver Sarcoma Initiative: “Details -- Synovial Sarcoma: A Detailed Review.”

American Academy of Orthopaedic Surgeons/American Association of Orthpaedic Surgeons (AAOS): “Abstract: Synovial Sarcoma.”

Sarcoma Foundation of America: “Sarcoma Clinical Trials.”

U.S. National Library of Medicine, “Search: Synovial Sarcoma.”

National Cancer Institute: “Childhood soft tissue sarcoma treatment (PDQ®) -- Patient Version.”

National Cancer Institute: “Adult soft tissue sarcoma treatment (PDQ®) -- Patient Version.”

National Human Genome Research Institute: “Translocation.”

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