Ganglion cyst Whēwhē pona
A ganglion is a fluid-filled swelling or cyst that is near a tendon or joint. Ganglion cysts look like smooth soft lumps under the skin. They are not harmful and are not cancer.
Causes of ganglion cysts
The exact causes of ganglion cysts are not known. They form when some of the jelly-like fluid (synovial fluid) that is in the joint leaks out.
Ganglion cysts are most common on the back of the wrist or the top of the foot, but they can happen anywhere.
Photograph of a ganglion cyst on the back of the wrist
Symptoms of a ganglion cyst
Ganglion cysts vary in size and are usually painless. If a ganglion cyst puts pressure on a bone or nerve around it this can cause some pain and discomfort. You may also find it hard to move your joints.
Diagnosing a ganglion cyst
Your healthcare provider can usually diagnose a ganglion cyst simply by seeing it. You will not need any further tests.
Treating a ganglion cyst
Ganglion cysts sometimes go away by themselves, without any treatment.
They are not harmful and are not cancer. But if they are large, they can sometimes be painful or can look unattractive. You only need treatment if the cyst is causing pain or problems when moving your joint, or if you think it looks very bad.
Your healthcare provider may recommend you wait to see if it changes.
If it is painful, using a simple, soft, elasticated wrist support when you are doing anything that makes it hurt might help. You can buy these from a pharmacy or online.
Do not try to burst or pop a ganglion cyst. This could cause an infection or skin damage
Treatment not using surgery
Your healthcare provider can try sucking out (aspirating) the fluid with a needle and syringe. The fluid is quite thick, so this does not always work, and the ganglion cyst often comes back. Having a steroid injection at the same time can help reduce the chance of it coming back.
If your healthcare provider is not experienced at giving steroid injections, they will be able to refer you to a provider who is.
Surgical treatment
If your ganglion cyst is causing a lot of pain or problems, your healthcare provider can refer you to a plastic surgeon or joint (orthopaedic) surgeon. They will tell you whether surgery is an option.
Surgery to cut out the ganglion cyst has the best chance of curing it. But this is not usually offered for all ganglion cysts within the public health system.
There is also a 5% to 10% chance the cyst will come back in the same position after surgery.
You can choose to pay to see a private plastic surgeon or private orthopaedic surgeon.
Find a plastic surgeon — New Zealand Association of Plastic Surgeonsexternal link
Find a surgeon — New Zealand Orthopaedics Associationexternal link