- Ganglion cysts are common benign tumors that are not related to nerve tissue (as implied incorrectly by the name).
- Can be located anywhere throughout the body but usually adjacent to or within joints and tendons, with the most common locations being the wrist, foot, and ankle
- Not a true cyst because microscopic examination does not show an epithelial lining
- Most are asymptomatic except for mass effect. Local nerve compression can result in pain, neuropathy, or activity limitation.
- Synonyms: synovial cyst; myxoid cyst; Gideon disease; Bible bump
- Can affect all age groups; unusual in children
- Most common in ages 20 to 40 years and 3 times as common in women
- Common in dorsal wrist, radial wrist, and dorsum of the distal interphalangeal (DIP) joint (referred to as a mucous cyst)
- Mucous cysts are usually seen in older patients.
- 60–70% of hand and wrist ganglion cysts are on the dorsal wrist; 15–20% are on the volar wrist.
- Prevalence of wrist ganglia in patients presenting with wrist pain is as high as 19%.
- Prevalence of ganglia in patients with a palpable mass in the wrist is as high as 27%.
- Reported prevalence in ankles is 5.6%.
Etiology and Pathophysiology
Pathogenesis is unclear. Cysts are filled with mucin and communicate with the adjacent joint space, tendon, and/or tendon sheath via a stalk. Several theories about their origin include:
- Herniation of synovial lining creates a one-way valve. Although this is supported by dye studies, the lack of a synovial (epithelial) lining in the cyst wall makes this less likely.
- Mucoid degeneration of connective tissue results in formation of hyaluronic acid, leading to cystic space formation. Studies haven’t confirmed this hypothesis.
- Joint stress leads to a tear in the joint capsule or tendon sheath allowing synovial fluid to leak into surrounding tissues. Local irritation leads to production of fluid and a pseudocapsule forms (explaining the lack of an epithelial lining).
- Recurrent stress may stimulate mucin production by nearby mesenchymal cells (seen on electron microscopy) resulting in cyst formation (1).
No specific genetic links have been found.
- Female > male
- Osteoarthritis for mucoid cysts
- Joint trauma (possible but not proven)
Commonly Associated Conditions
Mucous cysts are usually associated with osteoarthritis at the DIP joint.
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