What does the blood film show?
Marked anaemia, myeloblasts with Auer rods, thrombocytopaenia with no platelet clumps.
What does the bone marrow aspirate show?
Myeloblasts with maturation and eosinophilia. Eosinophilic precursors are increased in number. Some myelocytes have salmon-pink cytoplasm.
How would you interpret the immunophenotype on flow cytometry?
The abnormal blasts partially express B cell markers (CD19 and 79a). MPO, a myeloid marker, is positive. Although the blasts express B cell markers, this does not fulfill the criteria for diagnosis of mixed phenotype acute leukaemia (WHO 2017 classification).
References: WHO definition, EGIL definition
What is the diagnosis?
Acute myeloid leukaemia with t(8;21); RUNX1 (WHO 2017 classification)
t(8;21) leukaemias are frequently reported to express CD19 (Kita et al., Walter et al.)