Intratendinous supraspinatus cyst as a cause of shoulder impingement.

We report the case of a 29-year-old gentleman with shoulder impingement. An articular-sided intratendinous supraspinatus cyst was identified as the cause of his symptoms. Arthroscopic cyst debridement resulted in a good outcome at 1-year follow-up. Cysts around the shoulder are a well described pathological entity. They consist of different categories, including intraosseus cysts of the humeral head and glenoid, paralabral cysts and cysts associated with the acromioclavicular joint. Although paralabral cysts that lie intramuscularly or between the muscle bellies have frequently been reported, this is the first report of an intratendinous supraspinatus cyst with an intact rotator cuff. We describe the case, its management and the postsurgical outcome.