[Transformation from promyelocytic leukemia with t (15; 17) ( q22; q21) to acute monocytic leukemia with t (11; 17) (q23; q21) in a case].

To report on a case of therapy-related acute monocytic leukemia(t-AML) with t(11;17) (q23;q21)/MLL-AF17q after successful treatment for acute promyelocytic leukemia(APL) with t(15;17) (q22;q21)/PML-RARα.A MICM method (bone marrow morphology(M), immunophenotype(I), cytogenetics(C), and molecular biology(M)) was used for the diagnosis and classification of the disease at the time of onset and transformation.The patient was initially identified with typical morphology and immunophenotype of APL. She has carried t(15;17)(q22;q21) and PML-RARα fusion gene but was without t(11;17)(q23;q21) or MLL gene abnormalities. After 13 months of successful treatment, she has transformed to AML with typical morphology and immunophenotype. t(11;17)(q23;q21) and MLL-AF17q fusion gene were detected in her bone marrow sample, while no PLZF-RARα fusion gene was detected by real-time quantitative reverse-transcription PCR(RQ-PCR) and fluorescence in situ hybridization(FISH).t-AML is a serious complication after successful treatment of APL. t(11;17)(q23;q21) is not specific for the diagnosis of variant APL and can also be detected in t-AML. RQ-PCR and FISH are essential for the diagnosis of such patients.