MPO and acute myeloid leukemia: In the case described here, despite an aberrant CD7 expression in flow cytometry, routine diagnostics including cytology (Auer rods), immunohistology (myeloperoxidase and lysozyme expression), immunophenotyping by flow cytometry (Figure 1, Supplementary Figure S1), and the mutational profile (FLT3-ITD, CEBPA) led to the diagnosis of an AML.