Why Ganglion Cysts Develop
Ganglion cysts develop from mucoid degeneration of connective tissue associated with joints, tendons, ligaments, and tendon sheaths, typically triggered by chronic irritation, repetitive injury, or chronic ischemia. 1
Pathophysiology
The fundamental mechanism involves breakdown of collagen and connective tissue structures:
- Ganglion cysts lack a true synovial epithelial lining, distinguishing them from synovial cysts 1
- They result from myxoid (mucoid) degeneration of connective tissue in structures adjacent to or within joints, tendons, ligaments, and tendon sheaths 1, 2
- The cyst wall is composed of thin, fibrous tissue without lining epithelium, confirmed on histologic examination 2
Triggering Factors
The degenerative process appears to be initiated by mechanical stress:
- Chronic repetitive injury to the affected joint or tendon structure 1
- Chronic irritation of periarticular tissues 1
- Chronic ischemia affecting the connective tissue 1
- Association with osteoarthritis in many cases, though not universally required 3
Common Locations
Ganglion cysts can develop throughout the musculoskeletal system:
- Most commonly occur around the wrist and hand 4, 1
- Can develop in tendon sheaths, joints, and ligaments throughout the hand and upper extremity 5, 6
- Also found in the knee, ankle, and feet 1
- Rarely occur in unusual locations such as the proximal tibiofibular joint or intramuscularly 7, 2
Clinical Caveat
A critical pitfall is assuming all cysts near joints are ganglion cysts—they must be distinguished from synovial cysts (which have synovial lining and are more commonly associated with osteoarthritis), Baker's cysts, and other cystic lesions, as treatment approaches differ 2, 3. The presence of a thin fluid neck extending from the structure of origin (the "tail sign") on ultrasound is a reliable diagnostic feature when present 1.