Ganglion cysts are very common masses (lumps) that sometimes grow in the hand and wrist. The cysts are generally found on the top or the palm side of the wrist, the end joint of a finger (mucous cysts) or at the base of a finger. Ganglion cysts often have a specific cause and usually come from nearby joints or tendon sheaths.
These cysts can be painful, especially when they first appear or with constant or strenuous use of the hand. Ganglion cysts often change in size and may disappear completely. They are not malignant (cancerous).