A ganglion cyst is a fluid-filled protrusion that may develop near any joint, but most often occurs on or around the joints and tendons in the hands or feet. They are noncancerous lumps that are round or oval and usually measure less than an inch in diameter. Ganglion cysts that are on or near joints may interfere with movement. Although they are usually painless, if a cysts presses on a nerve it can cause pain, tingling, numbness, or muscle weakness.
Ganglion cysts that are not causing any symptoms may not require treatment. However if the ganglion cyst is interfering with joint mobility or causing pain, your doctor may recommend draining the fluid from the cyst or surgery.