Leukemic synovitis as a presentation of myelomonocytic blast crisis of chronic myeloid leukemia.

We describe a patient with a 2-month history of right shoulder monoarthritis and fever as the presenting symptoms of a subsequent diagnosis of chronic myeloid leukemia in blast crisis. Imaging studies showed changes consistent with leukemic infiltration of the soft tissues around the right shoulder joint and the proximal humerus. Immunophenotypic and morphologic analysis of the large number of cells obtained from the synovial fluid confirmed the shoulder synovitis to be an extramedullary manifestation of myelomonocytic blast crisis of chronic myeloid leukemia. The patient was not a candidate for aggressive chemotherapy treatment because of her poor overall condition, and she had no compatible donor for allogenic bone marrow transplantation. Her painful arthropathy was refractory to standard pain management but she achieved excellent pain relief with palliative radiation therapy. We conclude that the involvement of extramedullary sites by chronic myeloid leukemia blast cells can predate hematological blast crisis in some of chronic myeloid leukemia cases. Also, painful leukemic synovitis can be managed by low dose radiotherapy in a candidate who is refractory to chemotherapy and other medical therapy.