Synovitis in angioimmunoblastic lymphadenopathy with dysproteinemia simulating rheumatoid arthritis

We describe a patient with angioimmunoblastic lymphadenopathy with dysproteinemia who developed a symmetric, rheumatoid-like, peripheral polyarthritis. Radiographs of the involved joints revealed soft tissue swelling without erosions or cartilage loss. Rheumatoid factor and fluorescent antinuclear antibodies were negative, and C-reactive protein and erythrocyte sedimentation rate were normal. Synovial fluid analysis showed an inflammatory effusion (white blood cell count of 3,500/mm3, with 76% polymorphonuclear leukocytes). A closed synovial biopsy of the wrist revealed a mononuclear infiltrate consistent with angioimmunoblastic lymphadenopathy with dysproteinemia. Monthly parenteral chemotherapy treatment with high-dose methyl-prednisolone and cyclophosphamide resulted in remission of all manifestations of disease, including arthritis.