Ganglion Cyst

A ganglion cyst is the most common lump people find in the hand or wrist. It's a harmless fluid-filled sac that grows out of a joint capsule or tendon sheath, most often on the back of the wrist, on the palm side near the wrist artery, or right at a fingertip joint (where it's called a mucous cyst). The fluid inside is thick and jelly-like, similar to joint fluid but more concentrated.

Many ganglion cysts cause no symptoms beyond the lump itself. Others ache with wrist use, look cosmetically bothersome, or press on a nearby nerve. They often grow and shrink over weeks or months, and some go away on their own.

The most obvious sign is a smooth, firm, round bump, most often on the back of your wrist, on the palm side near the wrist crease, or at the last joint of a finger. The lump can change size over weeks, sometimes swelling up after heavy wrist use and shrinking back down with rest. Some cysts disappear entirely and then return.

Many ganglion cysts are painless: the concern is purely cosmetic. Others cause a dull ache that gets worse with gripping, pushing off the wrist (pushups, yoga), or bending the wrist fully. Occasionally a cyst presses on a nearby nerve, producing numbness or tingling in part of the hand. Some cysts hide beneath the surface (called occult ganglions) and cause unexplained wrist pain without any visible lump at all.

The diagnosis is usually obvious by exam, a smooth, firm lump in a typical spot that lights up when shined through with a small flashlight (because the fluid inside transmits light). Ultrasound confirms it's a fluid-filled cyst and shows the small stalk connecting it to the underlying joint. MRI is added when the diagnosis isn't certain, or when a hidden ganglion is suspected as the cause of unexplained wrist pain. X-rays check for underlying arthritis at the joint the cyst grew from.

Because a ganglion cyst is harmless, treatment is driven by how much it bothers you rather than by the lump itself. If it causes no symptoms, you do not have to do anything at all. When it aches, looks bothersome, or presses on a nearby nerve, care moves through the steps below, starting with the simplest.

Surgical removal is offered for symptomatic cysts that haven't responded to drainage, cysts that keep coming back, or cysts that are pressing on a nerve or blood vessel. The cyst plus its connecting stalk are removed to reduce the chance of recurrence.

External patient-education references and related OSI pages for additional background:

• AAOS OrthoInfo, patient education library
• OSI glossary, orthopedic terminology in plain language