Rheumatoid Arthritis with Rapid Destructive Arthropathy of the Shoulder due to Calcium Pyrophosphate Deposition.

A 67-year-old woman with rheumatoid arthritis presented with an untriggered hematoma in the right shoulder joint. Radiographic findings showed humeral head collapse and destruction of the glenoid fossa with ectopic calcification. Calcium pyrophosphate deposition (CPPD) in the synovial fluid was observed using a polarizing microscope. Histopathological findings revealed chronic inflammatory cell infiltration and giant cells surrounded by CPPD. The patient was diagnosed with rapid destructive arthropathy (RDA). Endoscopic shoulder joint debridement was performed. Postoperatively, active flexion improved from 40 to 75 degrees. This case highlights that CPPD can cause RDA in the shoulder, detectable with detailed histopathology.