Table 1.
The Evolving Classification of MDS
FAB 1982 | WHO 2001 | WHO 2008 | Blasts | Other Findings | Cytogenetic abnormalities |
---|---|---|---|---|---|
RA | RA |
RCUD RA RN RT |
<1% PB** <5% BM |
Uni or bi-lineage dysplasia* <15% RS |
25% |
RARS | RARS | RARS | None in PB, <15% BM | At least 15% RS | 10% |
RCMD RCMD-RS |
RCMD (−RS) | <1% PB*** <5% BM |
Dysplasia >10% in 2 cell lines, +/− RS, no AR**** |
50% | |
RAEB | RAEB-1 | RAEB-1 | <5% PB 5–9% BM |
Cytopenia, <1K/ul mono; dysplasia in 1 or more lines, no AR**** |
50–70% |
RAEB-2 | RAEB-2 | 5–19% 10–19 BM |
Cytopenia, <1K/uL mono, +/− AR; dysplasia in 1 or more lines |
50–70% | |
MDS-U | <1% PB; <5% BM |
Cytopenia, <10% dysplasia; cytogenetic abnormalities present |
50% | ||
MDS with 5q | <1% PB <5% BM |
Anemia, nml or incr. platelets, isolated del(5q), hypo-lobated megakaryocytes, no AR |
100% | ||
RAEB-T | 20–29% BM | ||||
CMML |
Stipulations:
If pancytopenia present, change to MDS-U;
If 1% blasts present, change to MDS-U;
if 2–4% PB blasts present, upgrade to RAEB-1;
if AR present, upgrade to RAEB-2.
Abbreviations: FAB, French American British classification; WHO, World Health Organization classification; RA, Refractory Anemia; RARS, Refractory Anemia with Ring Sideroblasts; RAEB, Refractory Anemia with Excess Blasts; RAEB-T, Refractory Anemia with Excess Blasts in Transformation; CMML, Chronic Myelomonocytic Leukemia; AML, Acute Myeloid Leukemia; RCMD, Refractory Cytopenia with Multi-lineage Dysplasia; RCUD, Refractory Cytopenia with Uni-lineage Dysplasia; MDS-U, Myelodysplastic syndrome-unclassified; AR, Auer Rods; PB, peripheral blood; BM, bone marrow; RS, ring sideroblasts (% indicates percent RS of total nucleated erythroid precursors).
Bold text indicates the current classification.