Ganglion cysts are the most common “masses” in the hand and wrist. They are “outpouchings” of a joint and are filled with joint fluid; this fluid looks like colorless, transparent jelly. You might notice that a cysts changes in size (getting bigger or smaller) and might or might not hurt. The most common places these form are on the back of the wrist, the palm side of the wrist, the palm side base of the finger, and the back of the end joint of the finger.
Location and appearance of the “bump” usually is diagnostic. If light can pass through the mass (“trans-illumination”), that is helpful as well. Cysts at the end joint of the finger often are associated with arthritis, and therefore are assessed by x-ray as well.
Observation of these is the initial treatment. Splints and anti-inflammatory medication can be used if your cyst is hurts with activities. Your doctor might offer aspiration, or withdrawal of fluid via a needle, but realize that this is associated with a high rate of recurrence. Surgical excision of the cyst along with part of the joint capsule or tendon sheath generally is successful but cysts still can recur. Your surgeon will discuss the best treatment options for you.