A ganglion cyst is a lump, typically round or oval, that can develop on the hand or wrist. It may be as small as a pea or it can grow up to about an inch in diameter. Generally speaking, ganglion cysts are nothing to worry about. Fairly common, they are usually harmless, aren’t cancerous, don’t spread, and often disappear on their own. The main problem with them is that people who have them may feel they are unsightly and, if they grow too large, they can hurt and limit function.
Ganglion cysts are most common in people between the ages of 15 and 40, although they can develop at any age.
“It’s not clear what causes ganglion cysts to form, but there is some evidence that they may be related to prior trauma or arthritis,” says J. Grant Thomson, MD, director of Yale Medicine's Hand & Microsurgery Program.