Table 1 Main Differences and similarities between ICC and WHO-4 and -5 classifications excluding CMML [3, 6, 7].
WHO-4 | WHO-5 | ICC | Differences |
|---|---|---|---|
Atypical CML, BCR-ABL1negative | MDS/MPN with neutrophilia (MDS/MPN-N) | Atypical CML (aCML) | Significant terminology changes in WHO 5ED; ICC deleted reference to the lack of BCR::ABL1 gene fusion in the name. Criteria essentially unchanged from revised WHO 4ED |
MDS/MPN with ring sideroblasts and thrombocytosis | MDS/MPN with SF3B1 mutation and thrombocytosis (MDS/MPN-SF3B1-T) | A. MDS/MPN with thrombocytosis and SF3B1mutation (MDS/MPN-SF3B1-T) B. MDS/MPN with ring sideroblasts and thrombocytosis, NOS (MDS/MPN-RS-T, NOS) | Disease now requires presence of an SF3B1 mutation. The ICC also recognizes a separate category – 'SF3B1 negative' cases defined by ring sideroblasts and thrombocytosis. There is limited outcome data on this subset |
MDS/MPN, U | MDS/MPN, NOS | MDS/MPN, NOS | Both made minor terminology change (“NOS” instead of “unclassifiable”). Criteria are unchanged from WHO 4ED |
Not recognized | Not recognized | Clonal cytopenia with monocytosis of undetermined significance (CCMUS) | Only ICC classification recognizes this category; considered within CCUS in WHO 5ED |
Not recognized | Not recognized | Clonal monocytosis of undetermined significance (CMUS) | Only ICC classification recognizes this category |
Not recognized | Not recognized | MDS/MPN with isochromosome (17q) (MDS/MPN-i(17q)) | Only ICC classification recognizes this category (provisional entity within MDS/MPN-NOS) |
