A ganglion cyst is a fluid-filled sac that forms near joints or tendons. These cysts are most commonly found on the back of the wrist, the palm side of the wrist, or at the base of fingers, though they can also appear on the ankles or feet. They develop when synovial fluid, which lubricates joints and tendons, leaks out and collects in a sac-like structure. Characteristics of a Ganglion Cyst: 1. Appearance: Smooth, round, or oval-shaped lump under the skin. 2. Size: Can range from pea-sized to l