Pigmented villonodular synovitis (PVNS)
This page explains about the causes, symptoms and treatment of pigmented villonodular synovitis (PVNS), from Great Ormond Street Hospital.
Pigmented villonodular synovitis (PVNS) is a type of benign tumour in the synovial tissue, which is the soft connective tissue of your joints that allows them to move smoothly.
It is rare in children and mostly affects young adults. In most cases the tumour occurs in the knee joint but any joint can be affected.
The hip joint is the second most common location, followed by the small joints in the hands, feet, ankle or elbow. Although it can be painful, it does not tend to spread beyond the affected area.
What are the signs and symptoms of PVNS?
People can experience symptoms of this condition differently but the most common signs of PVNS are:
swelling of a joint
joint effusion in the joint, which is a build-up of fluid which is usually bloody
aches and pain in the area affected
some people start limping and find it difficult to use the limb affected if the problem is with the leg, arm, hand or foot
How is PVNS diagnosed?
If someone has the symptoms, they should visit their GP as soon as possible.
The doctor will want to carry out a full physical examination and probably refer them for tests.
These tests may include an x-ray to look at the internal tissues and bones, an MRI scan, which produces a more detailed picture, and possibly an arthography, which is a type of x-ray that involves injecting the affected joint with a special substance which shows up on film.
What happens next?
Most adults with this condition will be offered an operation on the affected joint.
This treatment is also available for children with the condition, although doctors will take into consideration a child's age, overall health, the extent of the disease and whether it is causing any pain before they suggest it.
If the tumour is not causing the child pain or discomfort, it can be monitored by a doctor to check it doesn't spread, rather than be operated on.
But in some rare cases the tumour can invade the bone, which can add complications and mean that an operation is the best way forward.
The operation usually offered is called a synovectomy, during which the affected synovial tissue is removed.
Sadly there is a high rate of recurrence with this condition, so people may also be offered radiotherapy in future if the problem returns.
This has been used successfully to control recurrence of PVNS in adults but tends to be avoided with children because it can cause problems with growth and has been associated with other medical issues in later life.
Most children who have an operation on the PVNS will just be closely monitored afterwards.
The long-term outlook for a patient with PVNS depends on the size of their tumour, its location, the extent of the condition and its response to treatment.
With children, the age and overall health of the child can also play a part, as well as that child's tolerance for medical treatment, procedures and therapy.
Generally the prognosis is good because in most cases this is not an aggressive tumour. It is sometimes completely cured with surgery and in those cases where it recurs it usually causes minimal symptoms.