Synovial fluid immunocytology in the diagnosis of leukemic synovitis.

We describe a patient with leukemic synovitis complicating acute lymphoplastic leukemia. Leukemic cells were identified in the synovial fluid by an indirect immunofluorescent technique using monoclonal antibodies against early B cell antigens. Since focal leukemic lesions may be missed in synovial biopsy specimens, immunocytological analysis of joint fluids may facilitate early diagnosis of leukemic arthritis.