Amyloid arthropathy associated with multiple myeloma: polyarthritis without synovial infiltration of CD20+ or CD38+ cells
Patient 2 was a 77-year-old male with a history of coronary artery disease, non-insulin dependent diabetes, hypertension, chronic renal insufficiency and MM. Complications of MM included anemia, painful lytic bone lesions, a paraspinal extramedullary plasmacytoma, and worsening kidney disease requiring dialysis. Three months after the diagnosis, the patient presented with right shoulder, right knee and bilateral MCP pain. Examination showed swollen and tender knees in addition to warmth, erythema and tenderness in MCP joints bilaterally. A synovial biopsy of the right knee was performed. Cytologic examination of synovial fluid was reported as “few mononuclear cells”, but absolute or differential synovial fluid leukocyte counts were not enumerated. There were no crystals. Amyloid was demonstrated in synovial fluid sediment by Congo red staining. Treatment prior to the biopsy included two cycles of melphalan (8 mg/m2/day × 4 days) and prednisone (100 mg/day × 4 days) followed by palliative radiation therapy for bone lesions. The patient was taking prednisone 10 mg daily at the time of the biopsy. He passed away 3 months after the biopsy.