Synovial sarcoma is a form of soft tissue cancer. It often develops around the joints and can be difficult to diagnose. This condition can spread to other body parts, most notably the lungs. Because synovial sarcoma is so rare, scientists still have much to learn about it.

This article discusses the symptoms, causes, diagnosis, and treatment of synovial sarcoma.

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Sarcoma is a type of cancer. According to the National Cancer Institute (NCI), synovial sarcoma is a type of soft tissue sarcoma. Soft tissue sarcomas are cancers of the soft connective tissues.

Synovial sarcomas can form in many different parts of the body. Some common locations of this disease include the following:

  • arms
  • legs
  • feet
  • near joints, such as the ankles or wrists

Synovial sarcomas can also occur in the following locations:

As a 2021 article explains, the term “synovial sarcoma” is something of a misnomer. Synovial fluid functions to protect and lubricate the joints. However, synovial sarcomas do not form within the synovial fluid.

Many synovial sarcomas do develop near joints. This is because they originate from mutations of mesenchymal cells, which grow into connective tissues. They can also turn into lymphatic tissues and blood vessels.

How common is synovial sarcoma?

As a 2018 study notes, soft tissue sarcomas are rare. The authors explain that soft tissue sarcomas make up less than 1% of all neoplasms.

Neoplasms are tissue masses that form when cells grow and divide at an atypical rate. They can be benign or malignant, but cancers are malignant neoplasms.

Synovial sarcoma itself is a rare form of soft tissue sarcoma. The NCI states that they comprise around 5–10% of these cancers.

Learn more

Learn more about different types of sarcomas.

The earlier 2021 article details the main symptoms of synovial sarcoma. They include:

The NCI also considers numbness a symptom of synovial sarcoma. Moreover, as the tumor grows, it may form a noticeable lump.

Although this lump can cause pain and numbness when rubbing against a nerve, it should be painless.

As a 2022 review explains, scientists remain unsure about the causes of soft tissue sarcomas. Several factors may contribute to this disease, including:

  • genetic mutations, such as those in NF1, APC, and TP53 genes
  • exposure to radiation
  • exposure to carcinogens, such as arsenic and polyvinyl chloride

According to the NCI, around 1 in 3 synovial sarcomas occur in people under 30 years of age. Males are also slightly more likely to develop the condition. However, synovial sarcoma is not hereditary.

Synovial sarcomas are not easy to diagnose, as research from 2021 has shown that these cancers develop slowly. On average, people with synovial sarcoma will experience symptoms for 2 years before receiving a diagnosis.

When doctors suspect synovial sarcoma, they will first recommend an MRI scan. This technique can reliably produce accurate images of soft tissue sarcomas. If the MRI scan detects a tumor, doctors can continue testing.

To differentiate synovial sarcoma from other soft tissue sarcomas, doctors will perform a biopsy. This will involve a surgical procedure to remove some tissue from the tumor.

Healthcare professionals will then test the tumor sample in the laboratory.

If laboratory tests of the biopsy confirm synovial sarcoma, the next step involves treatment.

As the NCI explains, the first and primary form of treatment is surgery. The surgery will aim to remove as much of the tumor as possible, slowing the progression of the cancer.

Doctors may also recommend radiation therapy, either before or after surgery. This technique uses radiation to kill cancer cells.

In some cases, chemotherapy may be appropriate. Chemotherapy involves injecting chemicals into the bloodstream. These chemicals function to kill cancer cells, although they can also kill healthy cells.

Chemotherapy is useful when surgeons cannot remove every tumor. It may also be appropriate if cancer has spread to other body parts.

Because synovial sarcoma is rare, it is difficult for doctors to gauge survival rates accurately.

According to the NCI, between 36% and 76% of people with synovial sarcoma survive for at least 5 years after their diagnosis.

There is no way to prevent synovial sarcoma with any certainty.

Since exposure to radiation and carcinogens can lead to this cancer, avoiding them may lower the risk of developing this condition.

However, scientific research has not confirmed this.

Anyone with concerns that they have synovial sarcoma should speak with a doctor.

This includes people with unexplained pain, swelling, and lumps in the body.

If a doctor diagnoses synovial sarcoma early, there is more chance of treating it before it has metastasized.

A person living with or who has concerns about synovial sarcoma may wish to contact charities and groups for information and support.

Certain charities may provide financial and personal support to those living with cancer.

Official institutions can also provide up-to-date information about different cancers and the latest research regarding treatments.

Some charities and associations include:

This section answers some common questions about synovial sarcoma.

How quickly does sarcoma spread?

Synovial sarcoma is a rare form of cancer. Because there is so little data, scientists do not know how quickly this disease can spread.

Where does synovial sarcoma spread first?

According to research, the lungs are the most common location for synovial sarcoma metastases.

Synovial sarcoma is a form of soft tissue sarcoma and a rare form of cancer. It can present with few symptoms at first but very often spreads. It can cause pain, joint movement issues, and swelling. Treatment typically involves surgery, radiation therapy, and chemotherapy, often in combination.