What is a Ganglion Cyst
A ganglion cyst is a benign, fluid-filled soft tissue mass that most commonly develops around joints and tendons, particularly in the hand and wrist, representing the most common soft-tissue mass in these locations. 1
Definition and Pathophysiology
- Ganglion cysts are cystic lesions containing gelatinous material that lack a synovial epithelial lining 2
- These cysts develop from mucoid degeneration of connective tissue, thought to be caused by chronic irritation, chronic repetitive injury, and chronic ischemia 2
- They can develop in tendon sheaths, joints, and ligaments throughout the hand and other body locations 3
Common Locations
- The dorsal and volar aspects of the wrist are the most frequent sites 1
- Cysts may also arise from the flexor tendon sheath, interphalangeal joints, and extensor tendons 1
- Less common presentations include intraosseous and intraneural ganglion cysts 1
- Ganglion cysts can occur in the knee, ankle, feet, and dorsal foot 2, 4
- Proximal interphalangeal (PIP) joint ganglions are rare and typically affect patients older than 65 years 5
Clinical Presentation
- Most ganglion cysts are asymptomatic except for the visible lump 6
- When symptomatic, they may cause pain, weakness, or paresthesia 6
- Symptoms depend on location—dorsal foot ganglions are typically painful due to thin subcutaneous tissue and proximity to nearby arteries and nerves 4
- Cysts may interfere with joint mechanics, resulting in snapping, catching, and locking 2
- The two main patient concerns are cosmetic appearance and fear of malignant growth 6
Diagnostic Approach
- Diagnosis relies primarily on history and physical examination 1
- Transillumination and aspiration may serve as useful diagnostic adjuncts 1
- Ultrasound is recommended as the initial imaging modality to confirm the fluid-filled nature and distinguish cysts from solid masses 3, 7
- On ultrasound, ganglion cysts appear as hypoechoic masses with internal septations and lobulations, without significant vascularity on Doppler sampling 2
- A thin fluid neck extending from the structure of origin (tail sign) is a reliable ultrasound sign of a ganglion cyst 2
- MRI is reserved for suspected occult ganglion cysts or when there's concern about solid tumors including sarcoma 3, 7, 1
- On MRI, ganglion cysts appear as well-defined lobulated masses following simple or complex fluid signal intensity on all pulse sequences, with enhancing walls and internal septations on post-contrast images 2