Marked Response to Imatinib Mesylate in a Patient with Platelet-Derived Growth Factor Receptor Beta-Associated Acute Myeloid Leukemia

Abnormal platelet-derived growth factor receptor (PDGFR)-mediated signaling may cause hematologic neoplasm. The PDGFR beta (PDGFRB) gene, located at chromosome band 5q31-33, forms a fusion gene as a result of chromosome translocation. Although patients with PDGFRB rearrangement mostly present with myeloproliferative neoplasm and eosinophilia, acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) have also been reported in this population. Treatment with imatinib mesylate alone has been shown to have excellent long-term efficacy against myeloproliferative neoplasms; however, its long-term effects on ALL and AML have not been elucidated. A 75-year-old man was diagnosed with acute myeloid leukemia having the PDGFRB and cGMP-dependent protein kinase 2 fusion gene with additional genetic abnormalities. Continuous therapy with single-agent imatinib mesylate resulted in cytogenetic remission and decreased molecular burden for 9 months; however, the leukemia subsequently recurred, and the patient died 1 year after initiation of treatment. This case report supports the importance of cytogenetic analysis during patient screening.