Ganglion cyst

Ganglion cysts are common benign soft tissue swellings that often develop near joints or tendons. They are frequently observed in the wrist and hand, though they can occur in other areas of the body. These cysts are usually noncancerous but can cause discomfort or functional limitation depending on their size and location.

Anatomy and Pathophysiology

Common Locations

Ganglion cysts can arise in various regions of the body, most commonly near joints and tendon sheaths. The typical locations include:

• Dorsal wrist: The most frequent site, usually over the scapholunate ligament.
• Volar wrist: Located over the radial artery or flexor tendons.
• Fingers and toes: Often associated with distal interphalangeal joints, also called mucous cysts.
• Other uncommon sites: Ankle, foot, and less commonly near the knee or shoulder.

Pathophysiology

Ganglion cysts originate from the synovial lining of joint capsules or tendon sheaths. The exact mechanism is not completely understood, but they are thought to form through:

• Degeneration or myxoid change in connective tissue.
• Prolapse of synovial tissue through a joint capsule defect.
• Accumulation of mucinous fluid within a fibrous capsule.

Histologically, ganglion cysts consist of a dense connective tissue wall without a true epithelial lining, filled with viscous, gelatinous fluid rich in hyaluronic acid and other mucopolysaccharides.

Etiology and Risk Factors

Trauma and Repetitive Stress

Minor trauma or repetitive mechanical stress on joints and tendons is frequently associated with the development of ganglion cysts. This may lead to micro-injuries in the connective tissue, promoting cyst formation.

Age and Gender Predilection

Ganglion cysts are more commonly observed in individuals aged 20 to 40 years. Women are affected more often than men, particularly for cysts located on the dorsal wrist.

Genetic and Anatomical Factors

Certain anatomical variations, such as joint capsule weakness or predisposition to synovial herniation, may increase the likelihood of ganglion cyst formation. A familial tendency has also been suggested in some cases.

Clinical Presentation

Signs and Symptoms

Ganglion cysts typically present as a visible or palpable lump near a joint or tendon. The key features include:

• Visible swelling: A round or oval mass that may fluctuate in size over time.
• Pain or tenderness: Discomfort may occur, especially with joint movement or pressure on the cyst.
• Restriction of movement: Larger cysts can limit range of motion or grip strength, particularly in the wrist or fingers.

Complications

Although usually benign, ganglion cysts can sometimes lead to complications:

• Nerve compression: Cysts located near nerves may cause tingling, numbness, or weakness in the affected area.
• Recurrence: Even after treatment, cysts can recur due to incomplete removal or persistent joint stress.

Diagnosis

Clinical Examination

The diagnosis of a ganglion cyst is often made based on physical examination:

• Inspection and palpation: The cyst is usually firm, smooth, and mobile over underlying structures.
• Transillumination test: Shining a light through the cyst can reveal a fluid-filled nature in some cases.

Imaging Studies

Imaging can help confirm the diagnosis and evaluate the cyst’s relation to surrounding structures:

• Ultrasound: Useful for distinguishing cystic lesions from solid masses and assessing size and location.
• MRI: Provides detailed anatomical information, particularly for deep or complex cysts.
• X-ray: Generally normal but may be used to exclude bony abnormalities.

Differential Diagnosis

Other conditions should be considered when evaluating a soft tissue mass:

• Lipoma
• Tenosynovial giant cell tumor
• Synovial cyst
• Other soft tissue tumors or masses

Management

Conservative Treatment

Many ganglion cysts are asymptomatic and may not require active intervention. Conservative approaches include:

• Observation: Monitoring the cyst over time as some may spontaneously regress.
• Activity modification: Reducing repetitive stress or movements that exacerbate discomfort.
• Splinting or immobilization: Temporary wrist or joint splints can help alleviate pain and limit cyst enlargement.

Minimally Invasive Procedures

For cysts causing symptoms or functional limitation, minimally invasive interventions may be considered:

• Aspiration: Removal of cyst fluid using a needle. Recurrence is common.
• Corticosteroid injection: May reduce inflammation and recurrence risk, often combined with aspiration.

Surgical Management

Surgical excision is indicated for persistent, painful, or recurrent cysts:

• Indications: Pain, nerve compression, functional impairment, or patient preference.
• Surgical techniques: Complete excision of the cyst including its stalk and part of the joint capsule or tendon sheath to reduce recurrence.
• Postoperative care: Immobilization, pain management, and gradual return to activity to optimize healing.

Prognosis

Ganglion cysts generally have a good prognosis, especially with appropriate management. Key considerations include:

• Recurrence rates: Recurrence is common after aspiration but lower following surgical excision.
• Functional outcomes: Most patients regain full joint mobility and experience resolution of symptoms after treatment.
• Factors influencing prognosis: Cyst size, location, completeness of excision, and underlying joint pathology can affect outcomes.

Prevention

While ganglion cysts cannot always be prevented, certain strategies may reduce the risk of formation or recurrence:

• Ergonomic modifications: Adjusting wrist and hand positions during repetitive activities to minimize joint stress.
• Avoidance of repetitive stress: Limiting activities that place constant strain on joints and tendons associated with cyst development.
• Early intervention strategies: Prompt evaluation and management of new lumps or swelling may prevent enlargement and complications.

References

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4. Ogden JA. Skeletal Injury in the Child. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2000. p. 245-247.
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7. Sapega AA, Mont MA, Newman R. Soft tissue tumors of the hand: diagnosis and management. J Hand Surg Am. 1992;17(5):847-856.