Ganglionic Cysts are noncancerous lumps that can develop along the tendons or joints of the ankles and feet. Ganglionic cysts are typically round or oval and are filled with a jelly-like fluid. They can be painful if they press on a nearby nerve and can sometimes interfere with joint movement. It’s not clear what causes a ganglionic cyst to develop. It grows out of a joint or the lining of a tendon, and seems to occur when the tissue that surrounds a joint or a tendon bulges out of place. Although ganglionic cysts can develop in anyone, they most commonly occur in women between the ages of 20 and 40. Osteoarthritis as well as joint and tendon injuries can contribute to the likelihood of developing a ganglionic cyst in the future. If your ganglionic cyst is causing you pain, tingling, numbness, or limiting the movement of a joint, you should see your podiatrist to have it examined.