Classification of NHL
There are several historical systems for NHL classification. The Rappaport system was based on lymphoma cellular morphology and histology, with classification according to differentiation and diffuse or nodular appearance, and proved clinically useful in determining optimum treatment during the 1950s and 1960s2. However, this classification system was superseded in the 1970s when immunological concepts of the roles of T- and B-cells were developed, and a number of classification systems, including the Working Formulation and the Kiel classification systems, were introduced at this time2.
In 1994, the Revised European-American Lymphoma (REAL) Classification was devised with the aim of producing a unified system for malignant lymphoma. The REAL classification lists lymphoma types as distinct biological entities that can be reliably diagnosed through histopathology2. It separates peripheral and precursor cell lymphomas of both B- and T-cell origin, and may be applied to both nodal and extranodal lymphomas. The system is comprehensive and has been shown to be useful in predicting survival of different lymphoma subtypes2. The system has the advantage that lymphomas can be defined at a molecular level, identifying subtypes that could not be distinguished in the earlier classification systems1. In 1995 the REAL system was further revised by a working party of the World Health Organisation (WHO) to become the WHO/REAL classification.
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- Trϋmper L, et al. In: Non-Hodgkin's lymphomas. Mauch P, Armitage J, Coiffier B, Dalla-Favera R, Harris N, ed. Lippincott Williams & Wilkins 2004:3-19
- Harris NL, et al. Ann Oncol. 1999;10(12):1419-32.