Ganglion cyst

What is a ganglion cyst?

A ganglion cyst is a soft, fluid-filled lump that forms near a joint or tendon, most often on your wrist or hand. It's not cancer and it won't spread to other parts of your body.

What are the symptoms of a ganglion cyst?

You'll usually notice a smooth, soft lump under your skin before anything else. It can appear on the back or front of your wrist, at the base of a finger, near the top joint of a finger, or less often on the top of your foot.

• The lump usually measures 1cm to 3cm across, though it can grow larger and change size over time
• It can feel soft and spongy, or firm like bone, and it doesn't move under your skin
• Many ganglion cysts cause no pain at all beyond the lump itself, and up to 35% have no symptoms other than how they look
• If you do have pain, it's usually a dull ache that gets sharper when you put weight or pressure on the joint
• You might feel numbness, tingling or weakness if the cyst is pressing on a nearby nerve or tendon
• A cyst near the top joint of a finger can press on the nail bed and leave a groove or ridge in your nail

What causes a ganglion cyst and who is at risk?

Doctors don't know exactly why ganglion cysts form. The most widely accepted explanation is that a weak spot develops in the lining of a joint or tendon, letting synovial fluid (the fluid that lubricates your joints) leak out and collect in a sac under your skin.

Sometimes a cyst follows an injury, but often there's no clear trigger. Ganglion cysts are much more common in women than men, and most often affect people between 20–40 years old, though they can develop at any age.

Are there different types of ganglion cyst?

Ganglion cysts are grouped by where they form, and each type behaves a little differently.

• Dorsal wrist ganglion: the most common type, found on the back of the wrist. It mainly affects younger adults and often clears up by itself
• Volar wrist ganglion: found on the palm side of the wrist. It can affect young adults, and is also linked to wrist arthritis in older people. It sits close to the artery where you feel your pulse, so treatment needs extra care
• Flexor tendon sheath ganglion (sometimes called a seed ganglion): a small, firm lump at the base of a finger. It can feel like a dried pea and hurts when you grip something
• Dorsal digital ganglion (sometimes called a mucous cyst): forms near the top joint of a finger, usually in middle-aged or older people, and is often linked to early osteoarthritis (a condition that wears away the smooth surface of a joint) in that joint.

How is a ganglion cyst diagnosed?

Your doctor can usually diagnose a ganglion cyst just by examining your hand or wrist, so you're unlikely to need any tests. Scans aren't often needed, but if there's any doubt, an X-ray can check for arthritis in the nearby joint, or an ultrasound or MRI scan can confirm the diagnosis.

How is a ganglion cyst treated?

Most ganglion cysts are harmless and don't need any treatment. Many disappear by themselves and leaving one alone doesn't cause any long-term problems.

How long this takes can vary. Some guidance suggests many cysts clear up within several months to a year, while other patient information notes that the most common type, on the back of the wrist, can take up to 2 years to go away by itself.

Non-surgical options

• Watching and waiting to see if the cyst goes away by itself
• Taking Ibuprofen or another NSAID (a type of anti-inflammatory painkiller) to ease swelling and pain
• Wearing a wrist support or compression wrap, which you can buy from a pharmacy or supermarket
• Aspiration, where a doctor drains the fluid from the cyst with a needle and syringe, sometimes followed by a steroid injection to bring down swelling. This can be repeated if the cyst comes back

Try not to burst or pop the cyst yourself, as this could cause an infection or damage your skin.

Surgical options

If a cyst keeps causing pain or stops your joint from moving properly, your surgeon may recommend removing it. This is usually done as a day case procedure, meaning you go home the same day.

1. You'll usually have a general anaesthetic, so you're asleep, or a local anaesthetic, where your whole arm is numbed while you stay awake, because the cyst has a root that reaches into the joint
2. Your surgeon removes the cyst and closes the wound, usually with dissolvable stitches that don't need to be taken out
3. You'll need to keep the wound dry for 10–14 days while it heals
4. You may need simple painkillers such as paracetamol or ibuprofen afterwards, and occasionally something stronger for a few days.

Surgery isn't a guarantee that a ganglion cyst won't come back, and figures vary between sources. Some report recurrence rates of around 10% for cysts on the back of the wrist or near a finger joint, and around 30% for cysts on the palm side of the wrist, while other information describes a 50% chance of a ganglion cyst returning after surgery. Because of this, some surgeons are cautious about operating, particularly on cysts on the palm side of the wrist.

Possible problems after surgery include:

• a stiff joint or reduced grip strength
• scar tenderness, which usually settles within 6 weeks
• rarely, an infection.

When should I see a doctor?

See a GP if a lump is worrying you or if it starts getting bigger. You should also get it checked if it feels hard and doesn't move.

Get urgent advice from a GP or NHS 111 if the lump becomes very painful, hot or red. Redness can be harder to see on brown or black skin, so also pay attention to pain and heat.