[Polycythemia vera developed after a major molecular response to imatinib mesylate treatment in a patient with chronic myelogenous leukemia].

A 68-year-old man complained of dizziness and was referred to our hospital by his primary physician for evaluation of an elevated leukocyte count. In April 2002, soon after the chronic phase of chronic myeloid leukemia had been diagnosed, he was treated with imatinib. In March 2010, imatinib treatment was completed and the BCR/ABL fusion gene had become undetectable by real time quantitative PCR. Subsequently, leukocyte counts and the hematocrit gradually rose. In August 2012, a bone marrow aspirate showed hypercellular marrow with marked erythroid hyperplasia and the presence of the JAK2 gene V617F mutation. He was diagnosed with polycythemia vera. Phlebotomy and chemotherapy were started in addition to imatinib administration. Shortly thereafter complete blood counts returned to normal levels.