Proposal for updated WHO classification of myelodysplastic syndromes 2008
| Disease . | Blood findings . | Bone marrow findings . |
|---|---|---|
| *Bicytopenia may occasionally be observed. Cases with pancytopenia should be classified as MDS-U | ||
| † If the marrow myeloblast percentage is < 5% but there are 2% to 4% myeloblasts in the blood, the diagnostic classification is RAEB-1. | ||
| If the marrow myeloblast percentage is < 5% and there are 1% myeloblasts in the blood, the case should be classified as MDS-U. | ||
| ‡ Cases with Auer rods and < 5% myeloblasts in the blood and < 10% in the marrow should be classified as RAEB-2. | ||
| Refractory cytopenias with unilineage dysplasia (RCUD): | Unicytopenia or bicytopenia* No or rare blasts (<1%)† | Unilineage dysplasia; ≥10% of the cells of the affected lineage are dysplastic |
| Refractory anemia (RA) | < 5% blasts | |
| Refractory neutropenia (RN) | < 15% of the erythroid precursors are ringed sideroblasts | |
| Refractory thrombocytopenia (RT) | ||
| Refractory anemia with ringed sideroblasts (RARS) | Anemia No blasts | Erythroid dysplasia only ≥ 15% of erythroid precursors are ringed sideroblasts < 5% blasts |
| Refractory cytopenia with multilineage dysplasia (RCMD) | Cytopenia(s) No or rare blasts (<1%)† No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid lineages (neutrophil and/or erythroid precursors and/or megakaryocytes) < 5% blasts No Auer rods ± 15% ringed sideroblasts |
| Refractory anemia with excess blasts-1 (RAEB-1) | Cytopenia(s) < 5% blasts† No Auer rods < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 5–9% blasts† No Auer rods |
| Refractory anemia with excess blasts-2 (RAEB-2) | Cytopenia(s) 5–19% blasts Auer rods ± ‡ < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 10–19% blasts Auer rods ± |
| Myelodysplastic syndrome – unclassified (MDS-U) | Cytopenias ≤ 1% blasts† | Unequivocal dysplasia in less than 10% of cells in one or more myeloid cell lines < 5% blasts† |
| MDS associated with isolated del(5q) | Anemia Usually normal or increased platelet count No or rare blasts (< 1%) | Normal to increased megakaryocytes with hypolobated nuclei < 5% blasts Isolated del(5q) cytogenetic abnormality No Auer rods |
| Disease . | Blood findings . | Bone marrow findings . |
|---|---|---|
| *Bicytopenia may occasionally be observed. Cases with pancytopenia should be classified as MDS-U | ||
| † If the marrow myeloblast percentage is < 5% but there are 2% to 4% myeloblasts in the blood, the diagnostic classification is RAEB-1. | ||
| If the marrow myeloblast percentage is < 5% and there are 1% myeloblasts in the blood, the case should be classified as MDS-U. | ||
| ‡ Cases with Auer rods and < 5% myeloblasts in the blood and < 10% in the marrow should be classified as RAEB-2. | ||
| Refractory cytopenias with unilineage dysplasia (RCUD): | Unicytopenia or bicytopenia* No or rare blasts (<1%)† | Unilineage dysplasia; ≥10% of the cells of the affected lineage are dysplastic |
| Refractory anemia (RA) | < 5% blasts | |
| Refractory neutropenia (RN) | < 15% of the erythroid precursors are ringed sideroblasts | |
| Refractory thrombocytopenia (RT) | ||
| Refractory anemia with ringed sideroblasts (RARS) | Anemia No blasts | Erythroid dysplasia only ≥ 15% of erythroid precursors are ringed sideroblasts < 5% blasts |
| Refractory cytopenia with multilineage dysplasia (RCMD) | Cytopenia(s) No or rare blasts (<1%)† No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid lineages (neutrophil and/or erythroid precursors and/or megakaryocytes) < 5% blasts No Auer rods ± 15% ringed sideroblasts |
| Refractory anemia with excess blasts-1 (RAEB-1) | Cytopenia(s) < 5% blasts† No Auer rods < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 5–9% blasts† No Auer rods |
| Refractory anemia with excess blasts-2 (RAEB-2) | Cytopenia(s) 5–19% blasts Auer rods ± ‡ < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 10–19% blasts Auer rods ± |
| Myelodysplastic syndrome – unclassified (MDS-U) | Cytopenias ≤ 1% blasts† | Unequivocal dysplasia in less than 10% of cells in one or more myeloid cell lines < 5% blasts† |
| MDS associated with isolated del(5q) | Anemia Usually normal or increased platelet count No or rare blasts (< 1%) | Normal to increased megakaryocytes with hypolobated nuclei < 5% blasts Isolated del(5q) cytogenetic abnormality No Auer rods |