Diagnosis and classification of myelodysplastic syndromes

Myelodysplastic syndromes Myelodysplastic syndromes: (my-eh-lo-diss-PLASS-tik SIN-dromez) A group of disorders where the bone marrow does not work well, and the bone marrow cells fail to make enough healthy blood cells. Myelo refers to the bone marrow. Dysplastic means abnormal growth or development. People with MDS have low blood cell count for at… (MDSs) are neoplastic myeloid proliferations characterized by ineffective hematopoiesis hematopoiesis: (hi-mat-uh-poy-EE-suss) The process of making blood cells in the bone marrow. resulting in peripheral blood cytopenias. MDS is distinguished from nonneoplastic clonal myeloid proliferations by the presence of morphologic dysplasia and from acute myeloid leukemia acute myeloid leukemia: (uh-KYOOT my-uh-LOYD loo-KEE-mee-uh) A cancer of the blood cells. It happens when very young white blood cells (blasts) in the bone marrow fail to mature. The blast cells stay in the bone marrow and become to numerous. This slows production of red blood cells and platelets. Some cases of MDS become… by a blast threshold of 20%. The diagnosis of MDS can be challenging because of the myriad other causes of cytopenias: accurate diagnosis requires the integration of clinical features with bone marrow bone marrow: The soft, spongy tissue inside most bones. Blood cells are formed in the bone marrow. and peripheral blood morphology morphology: The study of the structure and form of an organism or one of its parts. , immunophenotyping, and genetic testing. MDS has historically been subdivided into several subtypes by classification schemes, the most recent of which are the International Consensus Classification and World Health Organization Classification (fifth edition), both published in 2022. The aim of MDS classification is to identify entities with shared genetic underpinnings and molecular pathogenesis, and the specific subtype can inform clinical decision-making alongside prognostic risk categorization. The current MDS classification schemes incorporate morphologic features (bone marrow and blood blast percentage, degree of dysplasia, ring sideroblasts, bone marrow fibrosis fibrosis: (fie-BRO-suss) Scarring of tissue. Fibrosis of the bone marrow is an feature seen in some types of unclassified myeldysplastic syndrome (MDS). , and bone marrow hypocellularity) and also recognize 3 entities defined by genetics: isolated del(5q) cytogenetic abnormality, SF3B1 mutation mutation: Any change or alteration in a gene. A mutation may cause disease or may be a normal variation. Paroxysmal nocturnal hemoglobinuria (PNH) occurs because of a mutation in the PIG-A gene of a single stem cell in the bone marrow. , and TP53 mutation. It is anticipated that with advancing understanding of the genetic basis of MDS pathogenesis, future MDS classification will be based increasingly on genetic classes. Nevertheless, morphologic features in MDS reflect the phenotypic expression of the underlying abnormal genetic pathways and will undoubtedly retain importance to inform prognosis and guide treatment.