Acute myeloid leukemia (AML) with chromosomal translocation t(8
21)(q22
q22.1) is a rare subtype, accounting for 4-8% of all cases of AML. Despite its rarity, it has a favorable outcome. The translocation event culminates in the formation of the Runt-related transcription factor 1 (RUNX1)::RUNX1 partner transcriptional co-repressor 1 (RUNX1T1) fusion protein, which is implicated in hematopoietic differentiation and maturation. Furthermore, monoclonal gammopathy of undetermined significance (MGUS) is characterized by the presence of monoclonal immunoglobulins in the blood or urine, serum M protein level of <
3 g/dl and <
10% clonal plasma cells in the bone marrow, with no accompanying end-organ damage associated with myeloma. The simultaneous occurrence of AML and MGUS is exceedingly rare. The present report describes the case of a male patient with AML and a RUNX1::RUNX1T1 fusion gene, not arising from the usual chromosomal translocation but rather from a complex translocation event involving t(8
17
21) (q22
q24
q22). The patient achieved complete remission (CR) following an idarubicin (12 mg/m