A hard knot under the skin, often plainly visible as a distortion in the skin (mine looked and felt like a protruding bone). Inside, the cyst is filled with a clear, jelly-like fluid. The origins of ganglion cysts are currently impossible to isolate; some are probably spontaneous while others may result from trauma. They most commonly occur between the bones of the wrist (on the top) and at the base of the finger. Most are benign, cause no pain, and will spontaneously disappear. Others, especially those in the wrist, are very painful and can cause permanent damage by forcing apart the bones or pressing against the nerves (accelerating or causing carpal tunnel syndrome). Initial treatment is usually aspiration--using a large needle to draw out the fluid in hopes that the cyst will shrink and disappear. However, many recur after this, and surgery may be needed to cut out the cyst and its stalk. This is a fairly delicate surgery and requires either a nerve block along with a sedative, or general anesthetic. Recovery period for wrist surgery is six to eight weeks. Unfortunately, 30% recur after the initial surgery.

PS The recovery period is way off. Two years later, mine still hurts with some frequency. Phooey.