Ganglion cysts are small, benign, fluid-filled sacs. They usually form on or near a joint or the covering of a tendon.

These cysts usually develop on the wrist, but they can appear on the hand, ankle, foot, or knee. They look like small lumps under the skin. Some people may refer to ganglion cysts as bible cysts.

Ganglion cysts are not cancerous and are usually harmless. If they cause pain, difficulty moving the joint, or if the person feels that they are unsightly, a doctor may remove them.

In this article, we detail what ganglion cysts are, their risk factors, and the treatments available to remedy them.

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These liquid-filled cysts develop along the tendons of the wrist. They are often small and painless and resolve on their own. Sometimes, though, they need to be removed. Medical Illustration by Bailey Mariner

Ganglion cysts are round or oval-shaped lumps that contain fluid. This type of cyst can range from the size of a pea to that of a golf ball.

They do not pose a significant medical threat. If one pushes on a nerve, however, it can cause pain. Also, depending on their size and location, these cysts can make some movements difficult.

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

A ganglion cyst always forms near a joint, and a doctor can usually recognize one by examining it visually.

They may be soft or hard, and they should be able to move freely under the skin.

  • Location: These cysts often occur on the top or back of the wrist. They may also appear on the palm side of the wrist, at the base of a finger, on top of a finger’s end joint, or on the ankle or knee joints.
  • Pain: Ganglion cysts may or may not be painful, depending on whether they press on a nerve.
  • Size: This can range from the size of a pea to that of a golf ball.

The area around the cyst may feel numb. If a cyst forms on the hand or wrist, the person may lose grip strength.

Doctors do not know what causes ganglion cysts. They may form when synovial fluid leaks from a joint.

Often, ganglion cysts attach to an underlying joint capsule or tendon sheath. They usually develop where a joint or tendon naturally bulges out of place.

Risk factors

Risk factors seem to include:

  • Age and sex: Ganglion cysts mostly affect people aged 20–50 and they develop more often in females than in males.
  • Overuse: People who use certain joints vigorously may be more likely to develop ganglion cysts. Female gymnasts, for instance, may be particularly prone to developing these cysts.
  • Joint or tendon injury: Ganglion cysts may be the result of repeated micro-injuries to tendons.
  • Trauma: They may form following a single incident or reoccurring small injuries.

Formation

Experts do not know exactly how ganglion cysts form.

However, it appears that joint stress may play a role, as the cysts often develop in sites of overuse or trauma. They may also develop following a synovial fluid leak from a joint into the surrounding area.

How or why this happens is not entirely clear.

A doctor usually shines a light through the cyst to see whether its contents are transparent or opaque. In a ganglion cyst, the liquid will be clear and thick.

Imaging scans, such as an X-ray, ultrasound, or MRI, can help a doctor determine the cause of the nodule and rule out other issues.

A ganglion cyst usually does not need treatment as long as it causes no discomfort or pain. In some cases, cysts may disappear without intervention, but some take several years to resolve completely.

A doctor will recommend some form of treatment if the cyst is pressing on a nerve and causing pain.

Removal

If the cyst is large, painful, or it causes problems, a doctor may recommend removing it with one of the following techniques:

Aspiration

This involves removing the fluid from the cyst. However, because the underlying structure remains, the cyst may form again. Some people need to undergo the procedure several times.

Surgery

A surgeon can make a small incision and remove the cyst and its stalk. Keyhole, or arthroscopic, surgery is also an option.

Recovery

After surgery, the person should keep the area covered and prevent it from accidentally bumping.

Other tips include:

  • following the doctor’s aftercare recommendations
  • wearing a splint for a few days, if the cyst was on the hand or wrist
  • using over-the-counter pain relief, if necessary
  • raising the extremity to reduce the risk of swelling

If discomfort persists, a person should see their doctor.

If a cyst causes discomfort, the following can help:

  • Adapting footwear: If the cyst is on a foot or ankle, shoes should not rub or irritate it. It may help to wear soft or open shoes, insert padding, or lace the shoes in a different way.
  • Immobilization: Moving the affected area may increase the cyst’s size. Wearing a splint or brace can help limit movement, and this may cause the cyst to shrink.
  • Pain relief: If the cyst is painful, over-the-counter pain medication, such as ibuprofen, can help.

What to avoid

A traditional remedy involves hitting a ganglion cyst with a heavy object, such as a book.

However, there is limited evidence that this method is safe or effective. Doctors do not advise people to do this as the blow could damage surrounding structures in the body.

Individuals should not try to “pop” their cysts, as this can lead to infection and it is unlikely to resolve the issue.

If a person experiences significant discomfort, they should speak with their doctor about treatment.

A ganglion cyst does not pose a serious health problem. However, if it is causing any discomfort or limitation of movement, a person should speak with a doctor, who may recommend a procedure to remove it.

Surgical procedures can leave a scar, and there is a risk that the cyst will form again.