The purpose of this review is to give an overview on the conceptual framework and major developments of the upcoming 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid tumours (WHO-HAEM5) and to highlight the most significant changes made in WHO-HAEM5 compared with the revised 4^(th) edition (WHO-HAEM4R) of lymphoid and stromal neoplasms. The changes from the revised 4th edition include the reorganization of entities by means of a hierarchical system that …