MYELODYSPLASTIC NEOPLASMS/ SYNDROMES IN THE 5TH EDITION OF THE WHO CLASSIFICATION OF HEMATOLYMPHOID TUMORS (2022)

Summary. Myelodysplastic syndromes (MDS) represent the heterogeneous group of the clonal myeloid neoplasms that arise due to the acquisition of the alterations in a hematopoietic stem cell. The diagnosis of MDS remains a significant challenge even at present. The classification of MDS underwent significant changes. For the first time, the WHO classification (2022) of the hematolymphoid tumors delineated the forms of MDS with defining genetic abnormalities and modifi d several forms that are morphologically defined. The classification of the childhood MDS was also refined. The unexplained cytopenias and clonal hematopoiesis of indeterminate potential capable of transforming to MDS are also discussed. The delineation of MDS entities based on molecular-genetic features requires novel approaches to the diagnosis, risk stratification, and treatment of patients. This review continues a series of papers published in this journal focusing on the analysis of the major changes in the WHO classification (2022) of the hematolymphoid tumors as compared to the previous WHO classification (2016) of the tumors of hematopoietic and lymphoid tissues.