Two new classifications for myeloid neoplasms were introduced in 2022: the International Consensus Classification (ICC) and the 5th edition WHO Classification (WHO-HAEM5). Both classifications build upon the previous WHO-HAEM4R (2017) incorporating recent advances in the biology of hematologic malignancies and clinical evidence. While both classifications share similar conclusions and emphasize genetic features over morphologic definitions, there are significant differences in the definition and nomenclature of several entities. This lack of alignment between WHO-HAEM5 and ICC presents diagnostic and therapeutic challenges. This presentation examines these similarities and key differences, offering a practical approach to diagnosing and classifying adult myeloid neoplasms amidst dual classification systems.

Learning Objectives: 

- Review the International Consensus Classification and WHO-HAEM 5th edition classification criteria for adult myeloid neoplasms.

- Summarize the key differences and similarities between the International Consensus Classification and the WHO-HAEM 5th edition classification systems.

- Analyze examples to discuss the reasoning behind each classification, highlight discrepancies between the two systems, and explore diagnostic implications.