What is a ganglion?
A ganglion cyst is a lump that develops under your skin and contains fluid. The cyst can range from the size of a pea to the size of a golf ball and are typically round or oval.
Most ganglions form near the wrist, hands and fingers, but they can form alongside any joint in the body. The fluid in the ganglion (called synovial fluid) comes from a joint or tendon through a narrow channel.