Diagnosis

Synovial sarcoma is usually slow-growing, so it can be years before a definitive diagnosis is made. In some cases, synovial sarcoma initially is diagnosed incorrectly as arthritis or bursitis.

Imaging methods that may be helpful include:

• Plain X-ray. In some cases, large areas of the tumor are marked or even outlined by calcifications. However, many synovial sarcomas don't show up on X-rays.
• Computerized tomography. CT scans often are useful in determining the extent of the tumor.
• Magnetic resonance imaging. An MRI can show the degree to which the tumor is affecting adjacent soft tissue, such as blood vessels and nerves.

A sample of the tumor can be removed with a needle and then studied under a microscope to help determine the best treatment. Synovial sarcoma can be mistaken for other types of sarcomas, so a correct diagnosis depends on experienced pathologists.