World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues. A progress report.

TLDR

The WHO classification of hematopoietic and lymphoid neoplasms was developed jointly by the European Association for Hematopathology and the Society for Hematopathology, building on the REAL framework that defines diseases by morphology, immunophenotype, genetics, and clinical features. In 1995, a Steering Committee established ten disease‑specific committees and a Clinical Advisory Committee to create disease lists, definitions, and address clinical relevance. The resulting classification was presented in 1997, closely matching the REAL system with minor updates and revised provisional categories based on data since 1994.

Abstract

The World Health Organization (WHO) classification has been developed under the joint auspices of the European Association for Hematopathology (EAHP) and the Society for Hematopathology (SH). First organized in 1995, the Steering Committee appointed 10 committees for T-cell and B-cell lymphomas and leukemias and myeloid and histiocytic tumors to develop a relevant list of diseases and establish definitions of each disease according to established criteria. The WHO classification uses the principles of the Revised European American Classification of Lymphoid Neoplasms (REAL), which defines each disease according to its morphologic features, immunophenotype, genetic features, postulated normal counterpart, and clinical features. The proposed classification was presented at the United States-Canadian Academy of Pathology meeting in 1997. The Steering Committee also appointed a Clinical Advisory Committee to ensure that the classification meets clinical needs and to resolve questions of clinical significance. The proposed WHO classification for lymphomas is similar to the REAL classification for lymphomas, with minor modifications and reassessment of provisional categories based on new data since 1994.