The 2022 classifications of lymphoid neoplasms

Classification of hematological neoplasms in the past 25 years has been generated through international efforts to achieve broad consensus among professionals. In recent years, the understanding of lymphoid neoplasms has advanced notably, particularly with the impact of genomic studies. Two classifications of these neoplasms were produced in 2022. The International Consensus Classification (ICC) was generated following the same successful process used for the third, fourth, and updated fourth editions of the World Health Organization (WHO) Classification of Hematologic Neoplasms, coordinated by a steering committee approved by the Executive Committees of the European Association for Haematopathology and the Society of Hematopathology. The topics were prepared by different working groups and subsequently discussed in the clinical advisory committee (CAC) meeting with the participation of a large group of pathologists, clinicians, and scientists who all approved the classification after reaching consensus on all topics. Simultaneously, the International Agency for Cancer Research (IARC) of the WHO has produced the fifth edition of the classification of these neoplasms with a group of professionals appointed by the agency who discussed the proposed classification in different meetings. The definition and criteria for diagnosis of many entities have been refined in both proposals. Terminology for some diseases has been adapted to the current knowledge of their biology. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many entities. Although most categories are similar in both classifications, there are also conceptual differences and differences in the diagnostic criteria for some diseases.