top of page

What is a Ganglion Cyst?

Ganglion cysts are small, benign, fluid-filled sacs. They can be attached to joints or arise from a tendon sheath, which is the covering over the tendon. They most commonly affect the wrist and hand, but they can appear on the ankle, foot, or knee. They form small lumps under the skin.

The cysts are not cancerous, and they are usually harmless. If they cause pain, make it hard to use the joint, or are especially unsightly, they may be removed.

Ganglion cysts mostly affect people between the ages of 15 and 40 years, and women are more susceptible than men. They are quite common, but relatively little is known about them. They appear, often on the back of the hand, as a round or oval-shaped lump that is filled with fluid. They can range from the size of a pea to that of a golf ball.

Beneath the skin, the cyst resembles a water balloon on a stalk.

A cyst does not pose a significant medical threat, but it can sometimes be troubling.

If it pushes on a nerve, it can cause pain or make some movements difficult. It can sometimes be a cosmetic problem because of the size.


The cause of ganglion cysts is unknown. They can appear suddenly or slowly, and can disappear on their own. They can also reappear for no reason. Exercise or increased use of the joint where the ganglion cyst has formed may cause it to grow larger over time. Resting the joint may help it get smaller.

Signs and Symptoms

Ganglion cysts usually are not painful. If they grow large, you may feel pressure or pain when bending the joint. If the cyst presses on a nerve, it may cause discomfort, tingling and numbness. You may have less range of motion in the area or less strength to grip things. Pain, if present, is usually not very intense.

  • Noticeable swelling or lump.

  • The lump is able to change its size, including going away completely only to return.

  • The lump is usually soft and immobile.

  • In some cases, the lump is painful and aching, particularly those at the base of fingers.

  • The ache and pain is made worse by moving any nearby joints.

  • The affected tendon may cause a sensation of muscular weakness.

  • The back of the hands and wrists are most commonly affected.

  • Other sites include the back of the knee (Bakers cyst), ankle, foot, palm and fingers.

  • The skin over the top of a ganglion cyst may feel smooth, round and rubbery.


  • Medical history

  • Physical examination

  • Ultrasound

  • X-rays

  • Needle aspiration (a fine needle is used to draw off fluid, which is then examined in a laboratory).

A diagnosis of ganglion cyst can often be made during the doctor’s visit. Sometimes an X-ray or magnetic resonance imaging (MRI) test will be ordered. X-rays will not show a ganglion cyst but they may show other problems. An MRI can find hidden cysts under the skin or reveal other causes of your pain.


Most ganglion cysts go away without treatment and some re-appear despite treatment. It may take a long time, up to 12 to 18 months, before it disappears. If it is not causing any pain, your health provider may recommend simply watching and waiting.

Other treatments may include:

  • Splinting. The area affected by the ganglion cyst is immobilized. A brace or splint will prevent further irritation caused when the joint moves. It will help the swelling go down and so that you feel more comfortable.

  • Needle aspiration. The fluid is drained from the ganglion cyst by using a needle. First, the area is numbed, then a needle is inserted into the cyst and all of the fluid is emptied. Because the entire cyst is not removed, more than 80% of the time the cyst will fill with fluid again. Aspiration is not recommended on volar wrist cysts. There is too great a risk for damage to blood vessels and nerves in this area.

  • Surgical excision. Anesthesia is administered so that no pain is felt during the surgery. A surgeon will cut out (excise) the entire ganglion cyst including the thin sleeve covering the tendon or joint. Excision greatly reduces the chance of the cyst coming back. Still, about 5 percent of them will regrow. Patients wear a splint for 2 weeks after surgery. While surgery is considered a safe choice, it carries risks and a longer recovery. There is a chance of more bleeding at the surgical site, healing problems, harm to blood vessels, nerves and tissues in the area, infection, scarring and pain.

Things to remember

A ganglion cyst is a benign ball of fluid that grows on a tendon or joint. While the cause is unknown, it is thought that small tears in the tendon membrane or joint capsule allow the contents to squeeze out. In many cases, ganglion cysts go away by themselves without the need for medical treatment. However, if you feel like you have a ganglion cyst and are experiencing discomfort, treatment options are available to alleviate pain.

For more information or to request an appointment, please contact Dr. Patrick McDaid, M.D. at

Featured Posts
Recent Posts
Search By Tags
bottom of page