The WHO classification of myelodysplastic syndromes.
| Disease . | Blood Findings . | Bone Marrow Findings . |
|---|---|---|
| Refractory anemia (RA) | Anemia No or rare blasts < 1 × 109/L monocytes | Erythroid dysplasia only < 10% grans or megas dysplastic < 5% blasts < 15% ringed sideroblasts |
| Refractory anemia with ringed sideroblasts (RARS) | Anemia No blasts | Erythroid dysplasia only < 10% grans or megas dysplastic ≥ 15% ringed sideroblasts < 5% blasts |
| Refractory cytopenia with multilineage dysplasia (RCMD) | Cytopenias (bicytopenia or pancytopenia) No or rare blasts No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid cell lines < 5% blasts in marrow No Auer rods < 15% ringed sideroblasts |
| Refractory cytopenia with multilineage dysplasia and ringed sideroblasts (RCMD-RS) | Cytopenias (bicytopenia or pancytopenia) No or rare blasts No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid cell lines ≥ 5% ringed sideroblasts < 5% blasts No Auer rods |
| Refractory anemia with excess blasts–1 (RAEB-1) | Cytopenias < 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) | Cytopenias 5–19% blasts Auer rods +/− < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 10–19% blasts Auer rods +/− |
| Myelodysplastic syndrome, unclassified (MDS-U) | Cytopenias No or rare blasts No Auer rods | Unilineage gran or mega dysplasia < 5% blasts No Auer rods |
| MDS associated with isolated del (5q) | Anemia < 5% blasts Platelets normal or increased | Normal to increased megakaryocytes with hypolobated nuclei < 5% blasts No Auer rods Isolated del (5q) |
| Disease . | Blood Findings . | Bone Marrow Findings . |
|---|---|---|
| Refractory anemia (RA) | Anemia No or rare blasts < 1 × 109/L monocytes | Erythroid dysplasia only < 10% grans or megas dysplastic < 5% blasts < 15% ringed sideroblasts |
| Refractory anemia with ringed sideroblasts (RARS) | Anemia No blasts | Erythroid dysplasia only < 10% grans or megas dysplastic ≥ 15% ringed sideroblasts < 5% blasts |
| Refractory cytopenia with multilineage dysplasia (RCMD) | Cytopenias (bicytopenia or pancytopenia) No or rare blasts No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid cell lines < 5% blasts in marrow No Auer rods < 15% ringed sideroblasts |
| Refractory cytopenia with multilineage dysplasia and ringed sideroblasts (RCMD-RS) | Cytopenias (bicytopenia or pancytopenia) No or rare blasts No Auer rods < 1 × 109/L monocytes | Dysplasia in ≥ 10% of cells in two or more myeloid cell lines ≥ 5% ringed sideroblasts < 5% blasts No Auer rods |
| Refractory anemia with excess blasts–1 (RAEB-1) | Cytopenias < 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) | Cytopenias 5–19% blasts Auer rods +/− < 1 × 109/L monocytes | Unilineage or multilineage dysplasia 10–19% blasts Auer rods +/− |
| Myelodysplastic syndrome, unclassified (MDS-U) | Cytopenias No or rare blasts No Auer rods | Unilineage gran or mega dysplasia < 5% blasts No Auer rods |
| MDS associated with isolated del (5q) | Anemia < 5% blasts Platelets normal or increased | Normal to increased megakaryocytes with hypolobated nuclei < 5% blasts No Auer rods Isolated del (5q) |