What are ganglions?
Ganglions are small sacs (cysts) filled with fluid that often appear as bumps on the hands and wrists. They can also develop on feet, ankles, knees, or shoulders. A ganglion can grow out of a joint capsule, which surrounds the joint, or a tendon sheath, which covers the tendon (the fibers connecting muscle to bone). Ganglions aren't cancerous.
Most people with ganglions notice that the bumps appear suddenly. Bumps may be very small or bigger than a cherry. Ganglions may get bigger as activity increases and more fluid collects in the sac. They may also shrink and may break and go away on their own.
Anyone can get a ganglion: adults between 15 and 40 years old are most likely to be affected.1 Children don't usually have ganglions, but if they do, the ganglion will very likely go away without any treatment.
What causes ganglions?
Experts don't know the exact cause of ganglions. They may be linked to:
What are the symptoms?
Ganglions are usually small, painless bumps and do not cause other symptoms.
Sometimes the bump can be tender to the touch, or there can be pain that gets worse with activity or pressure. If the ganglion puts pressure on nearby nerves, you may have tingling in your fingers, hand, or forearm. Some ganglions can weaken your grip or affect joint motion.
How are ganglions diagnosed?
A ganglion can usually be diagnosed based on how it looks and where it is. Your doctor will also feel the bump and shine a light alongside it. If the bump is a ganglion, the light usually shines through it.