Cause of Ganglion Cysts
The exact cause of ganglion cysts remains unknown, but the prevailing theory is that they form from mucoid degeneration of connective tissue, with extra-articular mucin "droplets" coalescing to form the cyst body, followed by development of the cyst wall and pedicle connecting to nearby joints or tendons. 1
Pathophysiology
The formation mechanism involves several proposed factors:
Mucin accumulation theory: Extra-articular mucin droplets coalesce to form the main body of the cyst, with the cyst wall and pedicle (connecting to synovial joints) forming only subsequently 1
Connective tissue degeneration: Ganglion cysts are thought to develop from mucoid degeneration of connective tissue, lacking a true synovial epithelial lining 2
Contributing Factors
While the precise etiology remains unclear, several factors have been implicated:
Trauma and joint tissue defects: Trauma and flaws in joint tissues may explain their appearance, though this is not definitively established 3
Chronic irritation and repetitive injury: Intratendinous ganglion cysts specifically are thought to develop from chronic irritation, chronic repetitive injury, and chronic ischemia 2
Post-surgical development: Ganglion cysts can develop following arthroscopic procedures, suggesting mechanical or inflammatory triggers 3
Anatomic Origin
Joint and tendon sheath origin: Ganglion cysts arise close to tendons, joints, ligaments, and tendon sheaths throughout the body 4, 2
Common locations: They can develop in tendon sheaths, joints, and ligaments throughout the upper extremity including the hand, wrist, and elbow 5, 6
Intra-articular variants: Though rare, ganglia can occur inside joints, arising from structures like the cruciate ligaments or meniscus 4
Important Clinical Caveat
Approximately 50% of ganglion cysts will spontaneously resolve without intervention, which is critical to understand when counseling patients about treatment options 1. This natural history supports initial observation in asymptomatic cases rather than immediate intervention.