Considering the patient’s initial diagnosis of AMKL, controversial cell morphology, and similarity to the immunophenotypes of Ewing sarcoma and CBFA2T3::GLIS2-positive AML, as well as the lack of molecular diagnostics, comprehensive additional immunophenotypic and molecular studies were performed to confirm the diagnosis of a secondary tumor, rather than extramedullary recurrence of AML. Here, GLIS2 is linked to acute myeloid leukemia.