Overview
A ganglion cyst is a harmless, fluid-filled lump that grows from a joint or tendon sheath, most often on the back of the wrist or the hand. It feels smooth and firm and can change in size, sometimes appearing suddenly. It is not cancerous and often causes no trouble beyond its appearance, though a large one can ache or press on a nerve. Many disappear on their own; those that are painful or bothersome can be drained or removed by a doctor.
Symptoms
- A smooth, rounded lump near a joint, often the wrist
- A lump that may change in size over time
- Usually painless, but sometimes aching
- Tingling or weakness if it presses on a nerve
- A firm or slightly springy feel
When to see a doctor
See a doctor to confirm a new lump, and if a ganglion is painful, growing, or causing tingling or weakness — do not try to burst it yourself.
Causes
Fluid leaking from a joint or tendon sheath into a small sac; the exact trigger is unclear, though joint wear or strain may play a part.