B cell surface marker analysis of synovial fluid cells in a patient with monoarthritis and chronic lymphocytic leukemia.

We describe a women with clinically quiescent chronic lymphocytic leukemia who developed monoarthritis consistent with her known diagnosis of osteoarthritis. Because of the concurrent chronic leukemia, we were concerned with the possibility of leukemic arthritis. Immunofluorescence of synovial fluid cells demonstrated an increase in B cells that failed to demonstrate monoclonality as determined by light chain class expression. However, biopsy of synovial tissue revealed leukemic infiltration. Local radiation therapy resolved the monoarthritis.