Identification of a Novel KRAS::ETNK1 Fusion Transcript in a Myelodysplastic/Myeloproliferative Overlap Syndrome With Eosinophilia: A Case Report

This work describes, to our knowledge, the first reported case of a patient with an MDS/MPN overlap syndrome harboring a novel KRAS::ETNK1 fusion transcript. The disease initially presented with eosinophilia, megakaryocyte expansion, mast cell infiltration, and a background of typical MDS/MPN‐associated mutations ( ASXL1 , TET2 , EZH2 , BCOR , and SETBP1 ). Following allogeneic hematopoietic stem cell transplantation, the fusion‐bearing clone disappeared due to a chromosome 12p deletion, and the disease evolved into secondary AML with distinct molecular drivers (MYB, EP300, FAT1, and GATA2). This case provides new insights into rare genetic alterations in MDS/MPN, possible mechanisms of immune‐mediated clonal selection after allogeneic stem cell transplantation, and the dynamics of leukemic evolution. Trial Registration : The authors have confirmed clinical trial registration is not needed for this submission