CBFA2T3::GLIS2 ‐positive acute leukemia with RAM and mixed T/megakaryocytic phenotype

Abstract

Herein, we present a rare case of acute myeloid leukemia (AML) with CBFA2T3‐rearrangement and the expression of megakaryocytic and lymphoid markers, highlighting the need for a high suspicion index in differential diagnosis and applying adequate workup to avoid misdiagnosing this entity. CBFA2T3::GLIS2 ‐positive AML is primarily found in infants with non‐down syndrome acute megakaryoblastic leukemia (non‐DSAMKL). Flow cytometry immunophenotyping plays an important role in recognizing the unique immunophenotype of bright CD56 expression with dim/negative expression of HLA‐DR, CD38, and CD45 termed the RAM immunophenotype in this entity. Still, CBFA2T3::GLIS2‐positive acute leukemia with T/megakaryocytic markers could be misdiagnosed as T‐lymphoblastic leukemia/lymphoma, early T‐cell precursor acute lymphoblastic leukemia/lymphoma, NK lymphoblastic leukemia, AML with minimal differentiation, or AML with myelodysplasia‐related changes.