Dysplasia in the myeloid series is defined by:

Granulocytic series:
Hypersegmented neutrophils (also seen in vit B12/folate deficiency)
Hyposegmented neutrophils (pseudo Pelger-Huet)
Hypogranular neutrophils or pseudo Chediak-Higashi (large azurophilic granules)
Auer rods – automatically RAEB II (if blast count < 5% in the peripheral blood and < 10% in the bone marrow aspirate); also note Auer rods may be seen in mature neutrophils in AML with translocation t(8;21)
Dimorphic granules (basophilic and eosinophilic granules) within eosinophils
Erythroid series:
Binucleated erythroid precursors and karyorrhexis
Erythroid nuclear budding
Erythroid nuclear strings or internuclear bridging (also seen in congenital dyserythropoietic anemias)
Loss of e-cadherin in normoblasts is a sign of aberrancy. PAS (globular in vacuoles or diffuse cytoplasmic staining) within erythroid precursors in the bone marrow aspirate (has no bearing on paraffin-fixed bone-marrow biopsy). Note: one can see PAS vacuolar positivity in L1 and L2 blasts (FAB classification; the L1 and L2 nomenclature is not used in the WHO classification)
Ringed sideroblasts (10 or more iron granules encircling one-third or more of the nucleus) seen on Perls Prussian blue iron stain (>15% ringed sideroblasts when counted among red cell precursors for refractory anemia with ring sideroblasts)
Megakaryocytic series (can be the most subjective):
Hyposegmented nuclear features in platelet producing megakaryocytes (lack of lobation)
Hypersegmented (osteoclastic appearing) megakaryocytes
Ballooning of the platelets (seen with interference contrast microscopy)Other stains can help in special cases (PAS and naphthol ASD chloroacetate esterase positivity) in eosinophils is a marker of abnormality seen in chronic eosinophilic leukemia and is a sign of aberrancy.
The IPSS scoring system can help triage patients for more aggressive treatment (i.e. bone marrow transplant) as well as help determine the best timing of this therapy. Supportive care with blood products and hematopoietic growth factors (e.g. erythropoietin) is the mainstay of therapy. The regulatory environment for the use of erythropoietins is evolving, according to a recent US Medicare National coverage determination. However, no comment on the use of hematopoietic growth factors for MDS was made in that document.Agents have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of MDS:

5-azacytidine: 21-month median survival
Decitabine: Complete response rate reported as high as 43%. A phase I study has shown efficacy in AML when decitabine is combined with valproic acid. Lenalidomide: Effective in reducing red blood cell transfusion requirement in patients with the chromosome 5q deletion subtype of MDS
Decitabine/cedazuridine (Inqovi) is a fixed-dosed combination medication for the treatment of adults with myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML).Chemotherapy with the hypomethylating agents 5-azacytidine and decitabine has been shown to decrease blood transfusion requirements and to retard the progression of MDS to AML. Lenalidomide was approved by the FDA in December 2005 only for use in the 5q- syndrome. In the United States, treatment of MDS with lenalidomide costs about $9,200 per month. The chemotherapy may be supported by other drugs like all-trans retinoic acid (ATRA), however the evidence of benefit is not clear.HLA-matched allogeneic stem cell transplantation, particularly in younger (i.e.