Wrist Lump or Mass: What Causes Bumps on the Wrist

What a wrist lump usually is

The wrist is a crowded space: eight small carpal bones, a dozen tendons running in lubricated sheaths, nerves, arteries and multiple joints. Lumps can arise from any of these. The location, feel and behavior of the lump point to its source.

Ganglion cysts

A ganglion cyst is the most common lump of the hand and wrist. It forms when thick joint fluid leaks from a joint capsule or tendon sheath and collects in a sac with a one-way stalk.

• Dorsal ganglion: on the back of the wrist, often over the scapholunate joint. It is the most common type and is more visible when you bend the wrist down.
• Volar ganglion: on the palm side near the base of the thumb, often lying close to the radial artery, which makes treatment more delicate.
• Occult ganglion: too small to see but may cause aching on the back of the wrist.

Ganglions are smooth, firm or rubbery, and usually painless. They often change size, getting bigger with activity and smaller with rest, and some disappear on their own. A light pressed against a ganglion often shows the glow of fluid inside.

They are most common in women aged 15 to 40, gymnasts and people with arthritis. Older adults may get ganglions linked to wear-and-tear arthritis of the wrist or finger joints.

Other common causes

• Carpal boss: a hard, bony bump on the back of the wrist at the base of the index or middle finger metacarpal. It does not move, is not fluid-filled and may ache with heavy gripping.
• Tendon sheath swelling (tenosynovitis): a soft, sausage-shaped swelling along a tendon. On the thumb side, painful swelling is often De Quervain's tenosynovitis.
• Giant cell tumor of the tendon sheath: a firm, painless, slowly growing lump, more common on the fingers but sometimes at the wrist. It is benign but can recur after removal.
• Lipoma: a soft, mobile fatty lump.
• Arthritis: rheumatoid arthritis can cause boggy swelling over the back of the wrist (synovitis) and rheumatoid nodules. Osteoarthritis causes bony spurs.
• Gout and pseudogout: crystal deposits (tophi) or sudden, hot, swollen joints.
• Epidermoid cyst or foreign body granuloma: after a cut or splinter.

Rare causes

• Aneurysm of the radial or ulnar artery: a pulsing lump, sometimes after trauma.
• Nerve sheath tumors (schwannoma): may cause tingling when tapped.
• Sarcoma: very rare in the wrist. Suspect it if a lump is hard, fixed, deep and steadily growing.

Telling wrist lumps apart

Symptoms that may come with a wrist lump

• Aching or weakness of grip, especially with push-ups or yoga poses that bend the wrist back
• Numbness or tingling in the thumb and first fingers if a volar lump presses on the median nerve, mimicking carpal tunnel syndrome; or in the ring and little fingers if a lump sits in Guyon's canal near the ulnar nerve
• Stiffness of several joints, suggesting arthritis
• Redness and heat, suggesting infection or gout

How doctors diagnose a wrist mass

A doctor will ask how long the lump has been there, whether it changes size, whether it hurts or causes numbness, and about injuries, arthritis and gout. They will examine its position, feel, mobility and tenderness, check circulation (the Allen test for volar lumps near the radial artery) and test nerve function.

• Transillumination: a penlight shows whether the lump contains clear fluid.
• Ultrasound: confirms a cyst, shows its stalk and checks its relation to the artery.
• X-ray: shows arthritis, a carpal boss, calcification or bone changes.
• MRI: for occult ganglions, solid masses or unclear cases.
• Blood tests: uric acid for gout, rheumatoid factor and anti-CCP for rheumatoid arthritis.

Treatment for a wrist lump

Ganglion cysts

• Watch and wait: recommended for painless ganglions. Up to half resolve on their own over months to years.
• Splint: a wrist brace during flares reduces aching, but long-term splinting weakens the wrist.
• Aspiration: drawing out the fluid with a needle, sometimes with a steroid injection. It is quick and done in clinic, but the cyst comes back in about half of cases. It is avoided for volar ganglions near the artery.
• Surgical excision: open or arthroscopic removal of the cyst and its stalk. Recurrence falls to roughly 1 in 10, but recovery takes several weeks and the scar can be tender.

Do not hit the cyst with a book (the old "Bible bump" remedy). It can injure the wrist and the cyst usually returns.

Other causes

• Carpal boss: activity modification, steroid injection or surgical removal of the bony bump.
• Tenosynovitis: rest, splint, ice, a short course of an anti-inflammatory if safe (follow the label dose), or a steroid injection.
• Lipoma and giant cell tumor: surgical removal if symptomatic or uncertain.
• Arthritis and gout: treatment of the underlying disease.

Frequently asked questions

What is the most common lump on the wrist?

A ganglion cyst. It is a smooth, fluid-filled lump that grows from a joint or tendon sheath, most often on the back of the wrist. Ganglions are harmless, often change size, and many shrink or disappear without treatment.

Is a hard lump on the wrist bone serious?

Usually not. A hard, immovable bump on the back of the wrist is often a carpal boss, a small bony overgrowth. Some ganglions also feel very firm. A lump that is growing, painful at night or fixed deep in the tissue should be examined and scanned.

Should I pop a ganglion cyst on my wrist?

No. Pressing, puncturing or hitting a ganglion at home can cause infection, bleeding or injury to tendons, nerves or the radial artery, and the cyst usually comes back. A doctor can drain it safely with a needle if it bothers you.

Can a wrist lump cause numbness?

Yes. A ganglion or other lump on the palm side of the wrist can press on the median or ulnar nerve, causing numbness or tingling in the fingers and grip weakness. That is a reason to see a hand specialist, because nerve pressure can be relieved by removing the lump.

Do wrist ganglion cysts come back after surgery?

Sometimes. After surgical removal, roughly 1 in 10 ganglions return, compared with about half after needle aspiration. Removing the stalk where it joins the joint lowers the chance of recurrence.