The study was aimed to investigate the different prognosis of acute myeloid leukemia (AML) with inv (16). A 13-year-old patient diagnosed as M4Eo presenting with bulky lymphadenopathy was reported, the curative process of patients was presented and the related issues were discussed. The karyotype and inv (16) were detected by conventional cytogeneties and fluorescence in situ hybridization (FISH), respectively, the immunophenotype was detected by flow cytometry. The results showed that conventional cytogenetics and FISH analysis revealed inv (16). Induction therapy included idarubicin and cytarabine. After complete remission, patient received consolidation theray containing high-dose cytarabine (HDAC). FISH analysis revealed poor response of patient to HDAC. It is concluded that bulky lymphadenopathy in AML with inv (16) may be a negative prognostic sign. FISH for inv (16) is specific and constitutes an reliable tool to be used for diagnosis and minimal residual disease (MRD).