The main cause of ganglion cyst is unknown, but it is thought to be caused by an underlying joint or tendon instability. This instability can be due to a number of factors, such as repetitive motion, overuse of the affected joint or tendon, or injury. Other possible causes include a previous injury to the affected joint or tendon, or an underlying medical condition such as arthritis or gout.
Ganglion cysts form when the joint capsule or a tendon sheath is weakened, causing the synovial fluid to bulge out and form a visible lump. This can be a result of a trauma to the affected area or can occur naturally due to wear and tear.
The most common sites for ganglion cysts are the wrist and hand, followed by the foot, ankle, and knee. Other sites such as the shoulder, elbow, and hip can also be affected. In some cases, multiple cysts can form in the same area.
Ganglion cysts are usually harmless and do not require treatment. However, if the cyst is causing pain or affecting movement, it may need to be surgically removed. In some cases, the cyst may also be drained with a needle.