InterLymph hierarchical classification of lymphoid neoplasms for epidemiologic research based on the WHO classification (2008): update and future directions

Abstract

Abstract After publication of the updated World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues in 2008, the Pathology Working Group of the International Lymphoma Epidemiology Consortium (InterLymph) now presents an update of the hierarchical classification of lymphoid neoplasms for epidemiologic research based on the 2001 WHO classification, which we published in 2007. The updated hierarchical classification incorporates all of the major and provisional entities in the 2008 WHO classification, including newly defined entities based on age, site, certain infections, and molecular characteristics, as well as borderline categories, early and “in situ” lesions, disorders with limited capacity for clinical progression, lesions without current International Classification of Diseases for Oncology, 3rd Edition codes, and immunodeficiency-associated lymphoproliferative disorders. WHO subtypes are defined in hierarchical groupings, with newly defined groups for small B-cell lymphomas with plasmacytic differentiation and for primary cutaneous T-cell lymphomas. We suggest approaches for applying the hierarchical classification in various epidemiologic settings, including strategies for dealing with multiple coexisting lymphoma subtypes in one patient, and cases with incomplete pathologic information. The pathology materials useful for state-of-the-art epidemiology studies are also discussed. We encourage epidemiologists to adopt the updated InterLymph hierarchical classification, which incorporates the most recent WHO entities while demonstrating their relationship to older classifications.

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Affiliated Institutions

• Macquarie University AU
• University of Chicago US
• Mayo Clinic US
• Roger Williams Medical Center US
• Inserm FR
• Institut d'Investigació Biomèdica de Girona ES
• Université Paris-Sud FR
• Douglass Hanly Moir Pathology AU
• National Cancer Institute US
• Université de Bourgogne FR
• Providence College US
• Institut Bergonié FR
• Boston University US
• UNSW Sydney AU
• Piedmont Reference Center for Epidemiology and Cancer Prevention IT
• Cancer Prevention Institute of California US
• National Institutes of Health US
• University of Nebraska Medical Center US

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