The World Health Organization classification of lymphomas.

The Revised European-American Classification of Lymphoid Neoplasms (REAL) classification has been validated by a multi-institutional study, and project data showed that it is both reproducible and clinically relevant. The new World Health Organization (WHO) Classification of Neoplastic Diseases of Hematopoietic and Lymphoid Tissues, as a joint project of the Society of Hematopathology and European Association of Hematopathologists, is an update of the REAL classification, with minor changes based on newly available information. We analyzed the incidence of different histological types of non-Hodgkin s lymphomas diagnosed in Zagreb University Hospital Center, which were reclassified according to the WHO classification. Furthermore, we present a conceptual grouping of lymphomas into four categories (indolent, aggressive, highly aggressive, and localized indolent).