Shoulder osteoarthritis - geyser sign
The main radiological features are:
- marked acromio-clavicular osteoarthrosis with a large related synovial cyst (Geyser sign).
- Advanced degenerative osteoarthrosis of the right glenohumeral joint.
- rotator cuff degenerative tears.
The geyser sign refers to the supra-acromial synovial cyst that appears as a shoulder pseudotumor associated with long-standing rotator cuff tear and advanced osteoarthritis of the shoulder. The synovial cyst is formed by the glenohumeral joint fluid that erupts superiorly through the AC interval into the subdeltoid bursa.