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A ganglion cyst is a bump or mass that forms under the skin. Most commonly, ganglions are seen on the wrist (usually the back side) and fingers, but they can also develop around joints on the shoulder, elbow, knee, hip, ankle and foot. Ganglion cysts form when tissues surrounding certain joints become inflamed and swell up with lubricating fluid. They can increase in size when the tissue is irritated and often can "disappear" spontaneously. These masses or cysts appear to grow sometimes but they are not tumours or cancerous.
Ganglions can be painless; however, cysts that press on a nerve may cause pain, tingling, numbness, and muscle weakness.
The diagnosis of ganglion cyst is made by physical examination. Medical tests such as x-rays may be used to confirm the diagnosis.
The treatment can consist of rest, splinting the affected joint and, in some cases, aspiration of fluid (medically removing the fluid from the cyst with a needle) is recommended. If a ganglion cyst tends to reoccur, surgical removal may be recommended.
The cause of ganglions is not always clear. There is no known cause for many of these cysts. Non-occupational factors or conditions such as rheumatoid arthritis have been associated with ganglion cysts. Occupational factors also play an important role in the development of ganglions. Those occupations that require workers to excessively overuse certain joints or repeated movements such as the wrist and fingers pose a risk for ganglion cysts. Some cysts form after an injury (both occupational and non-occupational).
- Fact sheet confirmed current: 2023-03-28
- Fact sheet last revised: 2017-09-12