What Is a Ganglion? What Is a Ganglion Cyst?

Ganglion cysts are fluid-filled swellings that tend to form on top of joints or tendons in the wrists, hands, and feet. They have the appearance of firm or spongy sacs of liquid and their insides consist of a sticky, clear, thick, jelly-like fluid. Ganglion cysts are idiopathic, which means they generally form for unknown reasons. As painless and benign (not dangerous) growths, ganglion cysts often do not require treatment and go away on their own.

According to Medilexicon's medical dictionary, a ganglion cyst is "A cyst containing mucopolysaccharide-rich fluid within fibrous tissue or, occasionally, muscle bone or a semilunar cartilage; usually attached to a tendon sheath in the hand, wrist, or foot, or connected with the underlying joint."

A ganglion is also a collection of nerve cell bodies located outside the central nervous system. This article refers only to fluid-like swellings that form on top of joints, tendons in the wrists, hands and feet (ganglion cysts).

Who gets ganglion cysts?

Women are more likely than men to develop ganglion cysts. The risk of ganglion cysts is also greater for those who stress the wrist and hand with regular repetitive movement, who have osteoarthritis, and who have injured joints or tendons in the hands or feet.

What causes ganglion cysts?

The exact causes of ganglion cysts remain unknown. However, some researchers and physicians believe that small cysts can form when trauma damages the tissue of a joint. A well-supported theory posits that ganglion cysts form because of a flaw in the joint capsule or tendon sheath that permits the joint tissue to protrude outwards.

What are the symptoms of a ganglion cyst?

A ganglion cyst usually appears as a stationary, smooth bump from 1 to 3 centimeters in diameter. The cyst may disappear and reappear, may be soft or firm, and it may change size. Sometimes, a ganglion cyst will cause pain, aching, or numbness if it presses upon nerves. When attached to a tendon, the cyst can make the affected area feel weaker.

How are ganglion cysts diagnosed?

A physical examination is generally sufficient for diagnosing a ganglion cyst. A doctor may also order imaging tests such as an X-ray, ultrasound, or magnetic resonance imaging (MRI) in order to learn more about the characteristics of the cyst and to rule out conditions such as arthritis and malignant tumors. Confirmation of a ganglion cyst also may be aided by aspiration - when a doctor uses a syringe to gather fluid from inside the cyst.

How are ganglion cysts treated?

Ganglion cysts often do not require treatments, as they will rupture and disappear on their own. However, it is possible to use a syringe to remove the fluid (aspiration) or resect the entire ganglion in a surgical procedure. Aspiration also may involve injection of a steroid for anti-inflammatory purposes and a splinting of the cyst area to prevent it from moving. There is no guarantee that ganglion cysts will not reappear after any type of procedure.

How can ganglion cysts be prevented?

Because the causes of ganglion cysts are not well-understood, there are not suggested preventive measures.