Basophilic Crisis of Chronic Myelogenous Leukemia

An 81-year-old woman with Ph1-positive chronic myelogenous leukemia developed blast crisis four years after diagnosis of the disease. In the blast crisis phase, hematological examination disclosed WBC 93, 000/ μ1 with basophilia in both the peripheral blood (40.0%) and bone marrow (33.2%), with increased numbers of immature basophils, such as basophilic promyelocytes, myelocytes and metamyelocytes. Electron microscopy of bone marrow cells showed immature and mature types, which contained granules characteristic of basophils. Toluidine blue metachromasia was evident in the basophils. Cytogenetic study revealed the Ph1 chromosome along with additional abnormalities. In view of these findings, it seems likely that basophilic crisis developed in this patient with chronic myelogenous leukemia.