[Successful treatment with imatinib for a patient with myeloid neoplasms with eosinophilia and abnormalities of PDGFRB due to t (5;14)(q33;q22)].

A 50-year old man with a 1-year history of eosinophilia presented with an eosinophil count exceeding 13,800/mm3 in the peripheral blood at the first visit. Bone marrow examination revealed that eosinophils accounted for 30% of the nucleated cell count, and G-band karyotyping analysis detected t (5;14)(q33;q22). Using peripheral blood FISH test, he was found to have platelet-derived growth factor receptor β (PDGFRB) locus rearrangement at 5q32-33. The level of eosinophils in the peripheral blood reduced markedly 3 days after the initiation of Imatinib mesylate, 400 mg daily. This treatment was administered for 2 years, after which the peripheral blood FISH test was negative for PDGFRB. In this disease, although most cases are with t (5;12), those with t (5;14) are relatively rare, and the long-term course of this translocation is unknown.