A case of lymphoproliferative disease presenting as juvenile rheumatoid arthritis: Diagnosis by synovial fluid examination

Abstract Lymphoproliferative disease can present as arthritis, most commonly mimicking acute rheumatic fever. The finding of arthritis rarely leads to the correct diagnosis, in fact, it frequently suggests inflammatory rheumatic diseases. We present a case closely resembling juvenile rheumatoid arthritis in which the diagnosis was made by demonstration of malignant cells In the synovial fluid at a time they were absent from the peripheral blood and initial bone marrow specimen. Closed synovial and bone biopsy specimens, the latter of an osteopenic area, revealed the infiltrative character of this disorder.