What is a ganglion in the foot (cyst)?

See below: It is a growth on the foot usually over a tendon or joint. It is variable in size and filled with a thick, gelatinous fluid.

Ganglion: A ganglion is an outpocketing of an injured or inflamed tendon that fills with a gelatinous fluid. It is usually responsive to drainage and compression therapy.

Ganglion details.: A ganglion rises out of a joint, like a balloon on a stalk. It grows out of the tissues surrounding a joint, such as ligaments, tendon sheaths, and joint linings. Inside the balloon is a thick, slippery fluid, similar to the fluid that lubricates your joints. They are typically painless, but can become symptomatic. You can press on them on top and side to side and often they will pop.