Causes of Ganglion Cysts of the Hand
Ganglion cysts of the hand are primarily caused by mucoid degeneration of connective tissue resulting from chronic irritation, repetitive injury, or chronic ischemia. 1
Pathophysiology
- Most current theories suggest that extra-articular mucin "droplets" coalesce to form the main body of the cyst, with the cyst wall and pedicle (connecting to a nearby synovial joint) forming subsequently 2
- Trauma has been postulated as an inciting factor, with approximately half of cases associated with direct trauma, particularly wrist hyperextension 3
- Chronic repetitive movements leading to microtrauma of joint capsules or tendon sheaths may contribute to cyst formation 1
- The cysts lack a synovial epithelial lining, distinguishing them from true synovial cysts 1
Common Locations
- Most commonly occur at the dorsal and palmar aspects of the wrist 4
- Can develop in tendon sheaths, joints, and ligaments throughout the hand 5
- May form in relation to the proximal interphalangeal (PIP) joints, though this is less common 4
- Can occur within tendons (intratendinous ganglion cysts) 1
Risk Factors
- More common in women, particularly in their twenties and thirties 4
- Occupations or activities involving repetitive wrist movements or chronic stress to the hand 2
- Previous hand or wrist injuries may predispose to ganglion formation 3
- PIP joint ganglions appear to be more common in older adults (over 65 years) 4
Natural History
- Approximately 58% of ganglion cysts will resolve spontaneously over time without intervention 6
- Cysts may fluctuate in size, sometimes growing rapidly following trauma 3
- Some cysts may cause symptoms including pain, weakness, or paresthesia, particularly when they compress nearby structures 6
- In rare cases, ganglion cysts can cause carpal tunnel syndrome when located in the volar aspect of the wrist 3
Diagnostic Considerations
- Ultrasound is the recommended initial imaging modality to confirm the fluid-filled nature of ganglion cysts 7, 8
- MRI is typically reserved for suspected occult ganglion cysts or when there's concern about solid tumors 8, 9
- On MRI, ganglion cysts appear as well-defined lobulated masses that follow fluid signal intensity on all pulse sequences 1
- On ultrasound, they present as hypoechoic masses with internal septations and lobulations without significant vascularity 1
Clinical Implications
- Most ganglion cysts are asymptomatic aside from the visible swelling 6
- When symptomatic, they may interfere with joint mechanics, resulting in snapping, catching, or locking sensations 1
- Patients often seek treatment due to cosmetic concerns or fear of malignancy, though ganglion cysts are benign 6
- A characteristic "tail sign" (thin fluid neck extending from the structure of origin) on imaging is a reliable indicator of a ganglion cyst 1
Understanding the underlying causes of ganglion cysts helps guide appropriate management, whether observation, aspiration, or surgical excision, depending on symptom severity and patient preferences 6.