As mutations occurring in the spliceosome gene SF3B1 are known to be enriched in patients affected by MDS/MPN-RS-T, the identification of ring sideroblasts is not considered to be required to confirm the diagnosis in the most recent WHO classification [3], as well as in the ICC [4], provided that SF3B1 somatic mutation is found with a VAF greater than 10%. This evidence concerns the gene SF3B1 and myeloproliferative neoplasm.