Ganglion cysts

A ganglion cyst is a noncancerous, fluid-filled lump that grows out of the lining of a joint or tendon, most often on the back of the wrist. The cyst holds a thick, clear, jelly-like fluid and is connected to the joint or tendon sheath by a stalk. Ganglion cysts are a common cause of lumps in the hand and wrist. They can change size over time and sometimes go away without treatment.

• A round, firm or rubbery lump, most often on the back of the wrist, but also on the palm side of the wrist, at the base of a finger, or near the last joint of a finger
• A lump that gets larger with activity and smaller with rest
• Aching or pain, especially with wrist motion or pressure on the lump
• Tingling, numbness, or weakness if the cyst presses on a nearby nerve

Some cysts are too small to see and are found only on imaging, yet can still cause wrist pain. A cyst near the fingernail, called a mucous cyst, is usually linked to arthritis in the end joint of the finger and may cause a groove in the nail.

The cause is not known. A cyst forms when fluid from a joint or tendon sheath collects in a sac that bulges out from it.

Ganglion cysts are more common in:

• Women, and in teens and younger adults
• People who put repeated stress on the wrist, such as gymnasts
• Joints affected by arthritis, especially the end joints of the fingers in older adults

The diagnosis is often made by examining the lump: its location, how it feels, and whether a light shone through it shows that it is filled with fluid. X-rays may be taken to look for arthritis or other bone problems. Ultrasound or MRI can confirm a cyst, find one that is hidden, or help tell it apart from other kinds of lumps.

Many ganglion cysts cause no problems and can simply be watched, and some go away on their own. Treatment is considered when a cyst is painful, limits activity, presses on a nerve, or is a concern because of how it looks.

Non-surgical options:

• Observation, with periodic checks
• A wrist splint or brace for a short time, which may ease pain and sometimes shrink the cyst
• Aspiration: draining the fluid with a needle, usually in the office; the cyst often returns because the stalk remains

Surgery: excision removes the cyst along with its stalk and the small part of the joint capsule or tendon sheath it grows from. It is an outpatient procedure, done through an open incision or, for some wrist cysts, arthroscopically. Cysts can come back after either aspiration or surgery.

Do not try to pop a cyst or hit it with a heavy object such as a book. This can injure the hand and is unlikely to make the cyst go away.

After aspiration, normal use usually resumes right away. After excision, the wrist may be in a dressing or splint for a short time, and tenderness and swelling can last a few weeks. Returning to regular activities usually takes a few weeks, and hand therapy is occasionally recommended for stiffness.