Amyloid arthropathy associated with multiple myeloma: polyarthritis without synovial infiltration of CD20+ or CD38+ cells
Patient 1 was a 58-year-old male with MM complicated by transfusion-dependent anemia, lytic bone lesions, and myeloma kidney requiring dialysis. He presented with left shoulder pain and swelling two months after diagnosis of MM, followed by bilateral hand and shoulder swelling with morning stiffness lasting hours. Examination demonstrated left second metacarpophalangeal (MCP) joint swelling, right flexor tenosynovitis, bilateral shoulder effusions, flexion contractures of both elbows, and decreased range of motion in the cervical spine. Joint aspiration revealed a synovial fluid cell count of 2500 cells/mm3 (6% PMN, 17% lymphocytes, 77% synovial lining cells). Repeat aspiration one week later revealed a cell count of 1050 cells/mm3 and amyloid in the synovial fluid sediment by Congo Red staining. There were no crystals in either aspirate. A synovial biopsy of the right shoulder joint was performed after another week. MM therapy, which had been initiated prior to the biopsy, included one cycle of melphalan (12 mg/d × 4 days), prednisone (60 mg/d × 4 days), and apheresis to treat renal failure suspected to have resulted from free Ig light chains. Joint symptoms improved with this treatment, but therapy was eventually halted due to nausea. The patient died four months after the biopsy.