HAEM4:Myelodysplastic Syndrome with Ring Sideroblasts and Multilineage Dysplasia: Difference between revisions

MDS-RS-MLD is a subtype of [[Myelodysplastic Syndrome with Ring Sideroblasts (MDS-RS)|MDS-RS]] which is features with the presence of ≥ 15% ring sideroblasts (RS) in erythroid precursor cells or ≥ 5% RS when ''SF3B1'' mutation is present. In prior version of WHO classification, it set refractory anaemia with ring sideroblasts (RARS) as one group and did not differentiate MDS-RS-SLD with MDS-RS-MLD.  In 2016 WHO criteria, MDS-RS-MLD and MDS-RS-SLD were recognized as two separate subtypes of MDS-RS. Compared to MDS-RS-SLD that mainly affects erythroid lineage, MDS-RS-MLD usually has more than one cytopenia and more than two dysplasia in the three myeloid lineages such as erythroid, granulocytic and megakaryocytic lineages. According to 2016 WHO criteria, bone marrow (BM) blasts should be <5% and peripheral blood (PB) blast content should be <1%. In addition, MDS-RS is usually lack of Auer rods, and MDS with isolated del(5q) or RS with secondary causes must be excluded. Ring sideroblasts are erythroid precursor cells in which iron laden mitochondria form a perinuclear ring that can be visualized as blue granules by Prussian blue staining. RS can be found in other clonal neoplasms such as myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis ([[MDS/MPN-RS-T]]).