Ganglion Cyst

What Is It, Causes, Symptoms, and More

Author: Lily Guo

Editor: Alyssa Haag

Editor: Józia McGowan, DO

Editor: Kelsey LaFayette, DNP

Illustrator: Jessica Reynolds, MS

Copyeditor: David G. Walker

Modified: Jan 06, 2025

What is a ganglion cyst?

A ganglion cyst is a small fluid-filled sac that typically forms over a joint space or tendon, most commonly found on the dorsal (i.e., back) wrist and, rarely, the volar (i.e., palm side) wrist; the base of the finger; and dorsum of foot. Although they are the most prevalent soft tissue masses in the hand, ganglion cysts can occur anywhere on the body, including the knee, shoulder, and back. Ganglion cysts are sometimes referred to as “Bible cysts" or "Bible bumps" since a common home remedy in the past was hitting the cyst with a Bible or other thick book to rupture or pop the cyst.

Fluid-filled sac forming in the dorsal wrist.

What causes ganglion cysts?

Ganglion cysts develop when dense connective tissue herniates (i.e., bulges) from beneath the tendon sheath, from ligaments forming connections to the joint, and from joint capsules. While the exact cause is unknown, ganglion cysts are believed to occur when a small tear forms in a joint capsule or tendon sheath, causing synovial fluid to extravasate (i.e., leak out) into surrounding tissue. Repetitive movement may contribute to cyst enlargement and worsen symptoms. While there are hypotheses that chronic joint inflammation could cause ganglion cysts, this is less likely as inflammatory changes are not typically associated with these cysts.

What are the signs and symptoms of a ganglion cyst?

A ganglion cyst presents as a firm, well-circumscribed nodule, usually 1 to 2 centimeters (cm) in diameter. It can feel firm or fluctuant, appearing smooth, round, and rubbery. Ganglion cysts are typically asymptomatic; however, individuals may experience swelling, pain, and difficulty moving the affected joint. Though benign, ganglion cysts can lead to muscle weakness and loss of sensory and motor function if they compress an underlying nerve. The cyst's size may change over time, and it can affect people of all ages, with greater prevalence in the second to fourth decades of life.

How is a ganglion cyst diagnosed?

Diagnosis often occurs through physical examination where a healthcare professional examines the mass, possibly using transillumination by shining a light onto the cyst. If the light passes through, indicating mucinous, gelatinous fluid; a ganglion cyst may be suspected. Solid cysts (e.g., lipoma, epidermal inclusion cysts) do not transilluminate. In some cases, ultrasound or magnetic resonance imaging (MRI) may be used to confirm the diagnosis.

How is a ganglion cyst treated?

Over 50 percent of individuals experience spontaneous resolution of ganglion cysts without treatment. Observation is often a viable option for diagnosed ganglion cysts. In cases where cysts persist and cause discomfort, healthcare professionals may perform aspiration where they drain the cyst with a needle (although recurrence is possible). For those with persistent or recurrent symptoms despite conservative therapy, surgery performed by a specialized hand surgeon may be necessary for removing the cyst.

What are the most important facts to know about ganglion cysts?

Ganglion cysts are small fluid-filled sacs that form on joint spaces or tendons, most commonly presenting on the wrist. Their exact cause remains unclear, but they are associated with small tears in joint capsules or tendon sheaths. While mostly asymptomatic, they can cause swelling, pain, and joint movement difficulties. Diagnosing a ganglion cyst involves physical examination; transillumination testing; and imaging tests, including ultrasound or MRI. Over half of the cases resolve spontaneously, and observation is often sufficient. Needle aspiration may be performed for symptomatic cases, but recurrence is possible. Surgery is considered for persistent or recurrent symptoms.

References

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