A rare case with typical acute promyelocytic leukemia morphology associated with isolated isochromosome 17q withoutRARα rearrangement

Isolated isochromosome 17q has rarely been reported in hematologic tumor patients. A 37-year-old man was admitted with fever and weakness. Blood routine test showed anemia and thrombocytopenia. The morphology and immunology of bone marrow cells conform to classic acute promyelocytic leukemia (APL). But the karyotype showed isolated isochromosome 17q without t(15;17) (q22;q12). Rverse transcriptase polymerase chain reaction (RT-PCR) for PML -RARa was negative and fluorescence in situ hybridization (FISH) analysis showed no RARa gene rearrangements.The patient responded poorly to all trans retinoic acid and traditional chemotherapy with daunorubicin and cytarabine and survived only 43 days after diagnosis. The pathogenesis and the best treatment choice for this kind of patients are not clear currently.