PVNS, rare in children and affecting mostly young adults, is considered a locally aggressive tumor of synovium because it may invade the adjacent bones, although this usually does not happen, except when the affected joint is the hip. Any joint can be affected although the tumor occurs most commonly in the knee joint. The hip joint is the second most common location, followed by the small joints of the hand, foot, ankle or elbow. A variant, giant cell tumor of tendon sheath, is a similar synovial tumor that occurs in tendon sheaths.

Although it can be painful, PVNS usually does not spread beyond the affected area. It does, however, have a high rate of recurrence after surgery.

• Swelling of a joint (usually painless)
• Joint effusion (fluid, usually bloody), in the joint
• Pain (sometimes)
• Sometimes limping or difficulty using legs, arms, hands or feet.

• X-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film. 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. This test can be used alone to diagnose PVNS.
• Arthography - a special x-ray of the affected joint that involves the injection of a radiopaque substance directly into the affected area. Often times, PVNS is first suspected when the joint is aspirated prior to the injection of the radiopaque contrast material because the aspirated joint fluid will contain old, dark blood, which is a sign of PVNS. MRI has, however, largely replaced the need for arthrography, but it is still sometimes used.

• your child's age, overall health, and medical history
• extent of the disease and whether it is causing pain
• whether the tumor has invaded the bone
• your child's tolerance for specific medications, procedures, or therapies
• how your child's physician expects the disease may progress
• your opinion or preference

There is a high rate of recurrence, however, after this operation is performed, so your child's doctor may also recommend radiotherapy if it recurs. This has been used successfully to control recurrence of PVNS, but is generally avoided in children because of growth issues and the concern about radiation associated malignancy later in life.

Patients who do develop recurrence usually experience minimal symptoms. As long as the bones remain unaffected, your child's doctor may recommend observation alone and will want to monitor your child's condition at routine intervals.

• the extent of the disease
• the size and location of the tumor
• the tumor's response to therapy
• the age and overall health of your child
• your child's tolerance for specific medication, procedures or therapies.