Arthroscopic debridement resolves rheumatoid arthritis-associated rice body synovitis in a 58-year-old male

Rice body synovitis is a rare, often misdiagnosed complication of chronic inflammatory diseases like rheumatoid arthritis (RA). These fibrin-collagen aggregates can cause pain and limited joint mobility, mimicking other shoulder pathologies. Early and accurate diagnosis is crucial for effective management, as non-specific symptoms often lead to diagnostic delays, impacting patient outcomes and requiring invasive interventions. This case report addresses the diagnostic and management challenges of this specific RA manifestation.

This report details a 58-year-old male patient with left shoulder rice body synovitis and a 25-year history of rheumatoid arthritis. Clinical presentation included a left shoulder mass for over 2 months, accompanied by pain and limited joint mobility within the previous week. MRI revealed marked capsular and bursal distension with multiple 0.5-0.8 cm rice body-like nodules and thickened synovium, characteristic of the "floating lotus sign." Laboratory tests confirmed active rheumatoid arthritis with elevated rheumatoid factor (128.0 IU/mL) and anti-cyclic citrullinated peptide antibody (86.0 RU/mL).

The patient underwent arthroscopic exploration and debridement, where multiple rice-grain-like bodies and proliferative synovial tissue were completely removed, followed by rotator cuff repair. Postoperative pathology revealed loose bodies composed of an amorphous necrotic core surrounded by fibrin, consistent with the pathological changes of rice body synovitis.

Postoperative management included analgesic treatment, staged shoulder rehabilitation, and rheumatology follow-up for reassessment of rheumatoid arthritis activity and optimization of disease-modifying antirheumatic drug (DMARD) therapy. At the 6-month follow-up, the patient's pain had completely resolved, and his shoulder's range of motion had returned to normal, achieving 180° abduction.