A ganglion cyst is a fluid-filled lump that typically appears near the joints or tendons of the hand or foot. They are usually harmless, but can be uncomfortable or unsightly.
Ganglion cysts are typically round or oval and can range in size from very small (a few millimeters) to larger than an inch in diameter. They often have a firm or rubbery consistency and are filled with a clear, colorless fluid. The fluid is composed of glycosaminoglycans, hyaluronic acid, and proteins, and is similar in composition to the synovial fluid that lubricates joints and tendons.
Ganglion cysts can develop in many different locations, most commonly on the top of the wrist, the palm side of the wrist, the base of the fingers, the outside of the ankle, and the top of the foot. They are often painless, but can cause pain and discomfort if they press on nerves or tendons. They can also cause cramping or weakness in the affected area.
Ganglion cysts typically do not require treatment, but they can be drained in a procedure known as aspiration. This is done by using a needle to puncture the cyst and draw out the fluid. The fluid is then examined for signs of infection and the cyst is filled with a steroid to reduce inflammation. In some cases, the cyst may need to be surgically removed.