A ganglion cyst is a swollen, closed sac under the skin. The sac is attached to the sheath of a tendon or may be attached to a joint. The cyst contains fluid similar to joint fluid. It can vary in size from a small pea to a golf ball. Ganglion cysts are the most common type of mass that occurs in the hand or wrist. They may also occur in the foot.
The cause of ganglion cysts is not known.
You may feel discomfort or pain. Sometimes the area of the cyst becomes swollen or disfigured. You may or may not see the cyst when looking at your hand or wrist.
An x-ray will be done to rule out any bone injuries. Your doctor may stick a needle into the cyst to take a sample of the fluid inside of it.
Unless a cyst hurts, it does not need to be treated. If it does hurt it may be treated with use of ice and anti-inflammatories. The fluid can be removed with a needle but the cysts tend to fill up again with fluid. If the cyst is painful or unsightly, it can be surgically removed.
Information obtained from The Sports Medicine Patient Advisor by Pierre Rouzier, MD