Abstract
Core-binding factor (CBF) abnormality-associated myeloid neoplasms incorporate acute myeloid leukaemia (AML) (CBF-AML) with translocation t(8;21)(q22;q22.1) (AML1/ETO fusion) and inv(16)(p13.1q22) or translocation t(16;16)(p13.1;q22) (CBFB/MYH11 fusion) abnormalities which confer a favourable prognosis following cytarabine-based induction chemotherapy. Accumulating evidence from the molecular studies have stratified CBF-AML into favourable and unfavourable subgroups based on the associated cooperating mutations that impact the outcome. We describe a case of acute myelomonocytic leukaemia with abnormal eosinophils (M4Eo) in a woman in her 20s who was found to have CBFβ/MYH11 fusion along with mutated c-KIT (exon 17) and KRAS (exon 2) genes by next-generation sequencing. She had an aggressive clinical course following initiation of cytarabine-based induction chemotherapy. The underlying mutational landscape may significantly influence the biological behaviour of otherwise favourable risk of CBF-AML cases.