Ganglion cyst

A harmless jelly-filled lump near a joint or tendon, usually on the wrist. Most need nothing, and hitting it with a book is a genuinely bad idea.

What it is

A smooth, fluid-filled swelling arising from a joint capsule or tendon sheath, containing thick clear jelly-like fluid.

They are the commonest soft tissue lump of the hand and wrist, most often on the back of the wrist, and they are entirely benign.

Many disappear by themselves, sometimes after months or years. Around half resolve without any treatment.

The traditional remedy of striking it with a heavy book is a real historical practice, and it is a bad idea: it can cause fractures and other injury, and the cyst usually comes back.

Treatment options are watching, aspirating with a needle, which is simple but has a high recurrence rate, and surgical excision, which has the lowest recurrence but carries the risks of surgery including scar tenderness and, rarely, nerve injury and stiffness. For an asymptomatic ganglion, doing nothing is usually best.

A ganglion at the base of a finger on the palm side can be tender when gripping. One at the fingertip, a mucous cyst, arises from an arthritic joint and can cause ridging of the nail.

Any lump that is hard, fixed, growing steadily, painful at night or not transilluminating deserves imaging rather than assumption.

Signs you might notice

A smooth, round, firm or rubbery lump, usually on the back or front of the wrist, or on a finger.

Varying in size over weeks, sometimes disappearing and returning.

Usually painless; sometimes aching, and worse with activity.

Occasionally causing weakness of grip, or pins and needles if it presses on a nerve.

Transilluminates: a torch held against it lights it up, because the contents are clear fluid.

See a GP for: a lump that is hard, fixed, growing steadily, or painful at night; any lump with numbness or weakness; a lump that does not transilluminate; or one that is red, hot and tender.

A lump in a child, or one growing rapidly, warrants imaging rather than reassurance.

How it can affect day-to-day life

The main reason people seek treatment is appearance rather than symptoms, which is a legitimate reason and worth saying rather than minimising.

NHS treatment for an asymptomatic ganglion is often not offered, and understanding why, that it is harmless and often self-resolving, helps more than being turned away without explanation.

Aspiration is quick and can be done in a clinic; recurrence is common, and it can be repeated.

After surgery, a period of stiffness and scar sensitivity is normal, and hand therapy helps.

For a mucous cyst at the fingertip, the underlying arthritic joint is the real issue, and the cyst may leak, which risks joint infection; a discharging one should be seen.

Wrist ganglia sometimes ache with heavy computer use, and adjusting position and taking breaks helps more than any intervention.

Supporting someone well

Do not hit it with anything. This causes injury and it comes back.

Consider leaving it alone; around half resolve on their own.

Get it looked at if it is hard, fixed, growing, painful at night, or causing numbness or weakness.

Ask about aspiration for a symptomatic one, understanding recurrence is likely.

Ask about surgery only where symptoms justify it, and about the risks of stiffness and scar tenderness.

Get a discharging fingertip cyst seen, because of infection risk.

Adjust wrist position and take breaks if it aches with repetitive use.

Ask for hand therapy after surgery.

Where to get help

A GP practice for assessment and reassurance.

Hand surgery or orthopaedics for symptomatic cysts.

Urgent assessment for a discharging mucous cyst or a red hot lump.

Arthritis UK for information on hand and wrist problems.