The myelodysplastic syndromes are acquired clonal disorders of myeloid pluripotent stem cells characterised by morphological abnormalities in the maturing cells of the granulocyte, erythroid and megakaryocyte lineages. Haemopoiesis is ineffective, giving rise to cytopenias. By convention they are separated from the acute myeloid leukaemias on the basis of the percentage of blasts present in the blood and bone marrow. The exception is the monosomy 7 syndrome of children. Males affected more frequently than females.
Symptoms reflect the cytopenias, i.e. anaemia, infection, bruising and haemorrhage.
Nucleated RBC may be present. Gross hypersegmentation is occasionally present. Platelet count usually raised specifically in the 5q- syndrome. Bone Marrow Aspirate Usually hypercellular. Nuclear abnormalities as in the peripheral blood.