We described a case of arthroscopically treated ganglion arisen from acromio-clavicle (AC) joint. Case: A 73-year-old man had elevation difficulties of his left shoulder for 5 years without any treatment. He came to our shoulder clinic with discomfort and oppressive pain from lump beside his left AC joint. Active motion was restricted to 120 degrees in flexion, 100 degrees in abduction. Radiographic evaluation revealed osteoarthritis changes at the AC joint; MRI showed 40 × 30 × 20mm cyst above the AC joint with massive rotator cuff tears involved in the SSP and ISP tendons. Needle aspiration confirmed that cyst was ganglion with temporary shrinkage for 2 weeks. Arthroscopic surgery was performed because of consistent symptom of ganglion. Arthroscopic evaluation confirmed that ganglion had connection with AC joint and arthroscopic ganglion resection accompanied with distal clavicle resection was performed. Shoulder symptoms were completely disappeared in a short time postoperatively and active motion reached 150 degrees in flexion and 150 degrees in abduction. This ganglion originated from AC joint and arthroscopic distal clavicle resection was thought to be an effective minimally invasive surgery for complete destruction of AC joint.
