The fifth edition of the World Health Organization Classification and the International Consensus Classification of myeloid neoplasms: evolving guidelines in the molecular era with practical implications

Abstract

Purpose of reviewThere have been major advances in our understanding of molecular pathogenesis of myeloid neoplasms, which prompt the updates in the classification of myeloid neoplasms in the fifth edition of World Health Organization Classification (WHO-5) and the new International Consensus Classification (ICC). The purpose of this review is to provide an overview of these two classification systems for myeloid neoplasms.Recent findingsThe definition, classification, and diagnostic criteria in many myeloid entities have been refined in WHO-5 and ICC with improved understanding of morphology and integration of new genetic findings. Particularly, molecular and cytogenetic studies have been increasingly incorporated into the classification, risk stratification, and selection of therapy of myeloid neoplasms. Overall, despite some revisions and discrepancies between WHO-5 and ICC, the major categories of myeloid neoplasms remain the same. Further validation studies are warranted to fine-tune and, ideally, integrate these two classifications.SummaryIntegration of clinical information, laboratory parameters, morphologic features, and cytogenetic and molecular studies is essential for the classification of myeloid neoplasms, as recommended by both WHO-5 and ICC.

Editorial: Hybrid or mixed myelodyplastic/myeloproliferative disorders: Current trends in diagnosis and treatment

“…Moreover, none of these somatic mutations, or any combination of them, nor any chromosomal aberration is pathognomonic for the entire group of mixed MDS/MPN or even for a single member-entity of the group. An additional logistic problem is that these are very rare and inhomogeneous diseases, and therefore, large databases and biobanks, which could potentially allow us to better analyze the disease biology, are not easily available ( 4 , 5 ).…”