Most are located under the skin, although occasionally they may be found in tendon or bone. The synovial or ganglionic cysts are connected to a nearby joint or tendon sheath by a small stalk. They therefore may be more resistant to treatment. Mucoid cysts, are not connected to a joint. If the cyst is located near the nail, it may cause the nail to grow funny.
Many mucous cysts are painless.
Some people are worried about the way it looks, others worry that it may be a serious problem. The cysts are more likely to cause pain or discomfort when they are on the foot, because of pressure created by shoes on them. Occasionally, the cyst encloses or presses on a nerve, causing a shooting, electric type of pain. Rarely, a doctor might order an arthrogram, where dye is injected into the cyst, in an attempt to see if it is connected to a joint or tendon sheath. The cysts may form on their own, or may branch out from a joint.