More common are bursas, ganglion cysts, inclusion cysts, fibromas or lipomas.
Ganglion cysts are best thought of as contained leaks of lubricating fluid of tendons or joints. While they are not generally harmful, they can be painful. Bursas are small sacs of fluid that the body produces to cushion prominent bones or protect tendons from irritation. On occasion they can become inflamed and irritat.