Possible causes of a lump on the wrist include a ganglion or epidermoid cyst and rheumatoid nodules. A hard bony lump may be an overgrowth of the bones in the wrist known as a carpal boss.

Lumps can develop along the joints and tendons on the back of the wrist or hand. Typically, the condition is not severe and requires no treatment. However, if it is painful, it may require medical attention.

Read on to learn more about the causes, diagnosis, and treatment of a lump on the wrist.

Ganglion cysts are round or oval-shaped, fluid-filled sacs that develop around the joints and tendons. They commonly appear on the back of the wrist. Ganglion cysts are not a cause for alarm.

A ganglion cyst resembles a balloon on a stalk and is filled with a thick, slippery, jelly-like fluid. The size of the cyst can differ, sometimes increasing when a person makes repetitive motions with the wrist.

Ganglion cysts are noncancerous and painless and can go away without treatment. However, this can take years, according to the United Kingdom’s National Health Service (NHS).

Symptoms of a ganglion cyst can include:

  • muscle weakness
  • tingling
  • numbness
  • pain
  • difficulty moving the wrist

Healthcare professionals do not know what causes ganglion cysts to form. They occur when the surrounding tissue of a joint or tendon swells to an inappropriate extent.

To diagnose a ganglion cyst, a doctor can apply pressure to the cyst to examine tenderness and overall discomfort. The doctor can also recommend X-rays and MRI scans to rule out other conditions, such as tumors or arthritis.


If a ganglion cyst is painless, it may require no treatment. However, if the cyst causes pain and inhibits joint movement, a doctor may recommend:

  • Aspiration: A doctor will drain fluid in the cyst using a needle and syringe. However, the ganglion cyst may flare up over time.
  • Immobilization: Repetitive tasks can worsen ganglion cysts. Immobilizing the affected area using a brace or splint will help ease tension in the nerves, relieving pain.
  • Surgery: A surgeon can remove the cyst when other treatment options do not work.

Learn more about the home remedies a person can try here.

Short for a carpometacarpal boss, a carpal boss occurs when there is an overgrowth of the carpal bones that constitute the wrist. The overgrowth results in a firm lump on the back of the wrist.

Although healthcare professionals do not know the cause of a carpal boss, researchers believe that the condition results from direct trauma or repetitive movements of the wrist, such as those necessary when playing racket sports.

The primary symptom of a carpal boss is a firm lump that develops at the back of the wrist. The majority of people do not experience any other signs. However, others may experience pain when they move the wrist or when the lump becomes tender.

To diagnose a carpal boss, a doctor will perform a physical examination and move the wrist in different directions to check the range of motion.

The doctor may touch the lump to check whether it is soft or hard. They might also do X-rays or MRI scans to examine the bones and tendons of the wrist for those experiencing intense pain.


Carpal boss requires no treatment if the condition does not cause any symptoms. However, when the bump is tender and painful, a doctor might recommend the following treatment options:

  • wearing a splint to immobilize the wrist
  • placing ice on the affected area
  • taking over-the-counter (OTC) medications, such as ibuprofen and acetaminophen
  • injecting corticosteroids into the lump

Surgery to remove the bump on the wrist may be necessary if conservative treatment has not worked after 6 weeks.

Epidermoid cysts, or epidermal inclusion cysts, are small lumps filled with keratin that develop underneath the skin.

While these cysts are painless, they can rupture and become inflamed, causing pain.

Symptoms of an epidermoid cyst include:

  • tenderness
  • swelling
  • flushed skin around the area
  • a benign round lump under the skin

Keratin buildup is the primary cause of epidermoid cysts. Keratin is a protein that occurs naturally in skin cells. If the protein becomes trapped under the skin, a cyst develops. Skin trauma may also cause the development of cysts.

To diagnose an epidermal inclusion cyst, a doctor will examine the lump and the surrounding skin of the affected area.


Most uncomplicated epidermoid inclusion cysts do not require treatment, and some may resolve spontaneously. However, if the cyst ruptures and is swollen, painful, or flushed, treatment may be necessary.

In such cases, treatment options include:

  • antibiotics
  • injecting steroids into the bump
  • draining fluid from the cyst

GCTTSs are benign nodular tumors that occur on the tendon sheath of the hands. According to 2013 research, the GCTTS is one of the most common types of benign tumors that affect the hand, after ganglion cysts. However, despite this, the condition itself is rare, affecting approximately 1 in 50,000 people.

The National Organization for Rare Disorders state that GCTTSs are slow-growing and noncancerous and are typically painless. However, they can occasionally be painful, and, eventually, a person may experience a “locking” or “catching” sensation.

To diagnose a GCTTS, a doctor can perform X-rays, ultrasound scans, or MRI scans to examine the affected tendons and ligaments.


A doctor will recommend a marginal excision to remove tumors.

Sometimes, they will suggest a complete excision of the tumor because of its close association with the synovium of the tendon sheath or the joint.

RA is an autoimmune condition that causes the immune system to attack the joints, causing pain or joint damage.

Approximately 25% of people with RA have rheumatoid nodules. These are round lumps that are firm or tender to the touch and may appear on the hands and wrists. The nodules usually move when a person presses them.

A person with RA may experience the following symptoms:

To diagnose RA, a doctor will perform a series of physical examinations and lab tests. The physical exam includes:

  • touching the affected joints to check for tenderness
  • moving the joint to examine the range of motion
  • looking for inflammation, swelling, and redness

A doctor may also do blood tests or imaging tests, such as X-rays or ultrasound or MRI scans.


To treat and manage RA, a doctor will prescribe disease-modifying antirheumatic drugs (DMARDs), which can slow the disease and help prevent joint deformity. They may also prescribe biologicals, or biological response modifiers.

Other ways in which people can manage their symptoms at home include:

Learn more about the treatment options and home remedies for RA here.

A lump on the wrist does not necessarily pose a health risk. However, in some cases, it may require medical attention. It would be best to book an appointment with a doctor, especially for a lump that:

  • is painful
  • has grown rapidly
  • seems infected
  • co-occurs with symptoms such as tingling, muscle weakness, numbness, and difficulty moving the wrist

Typically, a lump on the wrist is not a cause for concern. The lump can result from various underlying conditions, such as RA or a ganglion cyst, epidermal inclusion cyst, GCTTS, or carpal boss.

However, a painful lump on the wrist that appears infected and has grown rapidly may warrant medical attention.

A doctor will develop a treatment plan that is appropriate to the severity of the condition.