Ganglion Cysts

Ganglion and Tendon Sheath Cysts are fluid filled lumps which form beneath the skin on the hand or fingers. They arise from a small slit or area of weakness in the fibrous covering over a joint or tendon. With hand use, joint fluid or tendon sheath fluid may then leak into the fat beneath the skin. The body responds to this leak by forming a fibrous wall around the fluid (see figure). These cysts usually have a firm feel and may vary in size from week to week. Occasionally, they may disappear completely or arise again months or years later. The most common sites include the back or front side of the wrist or the base of the fingers. Cysts which arise near the nailbed are referred to as mucous cysts and arise from the small finger joints.