A Case of Large Rice Body Containing Cyst With an Irreparable Rotator Cuff Tear and Hill-Sachs Lesion Treated With Reverse Shoulder Arthroplasty.

Subacromial-subdeltoid bursitis with rice bodies, associated with shoulder instability, is uncommon. The pathogenesis of rice body formation remains unclear; however, it is considered a nonspecific response to chronic inflammation. We present the case of a 79-year-old woman with subacromial-subdeltoid bursitis of the right shoulder, numerous rice bodies, and rheumatoid arthritis (RA). She had a history of right shoulder dislocation, an irreparable rotator cuff tear, and a large Hill-Sachs lesion. She underwent reverse shoulder arthroplasty (RSA) with rice body removal and showed symptom improvement. RSA is a definitive treatment that can address three key issues: rice bodies caused by RA, rotator cuff deficiency, and instability from humeral bone loss.