Hémopathies malignes : définition et différentes variétés selon la classification de l'OMS 2001

The definition of the different types of neoplasias arising from haematopoietic cells as given by the WHO classification in 2001, are summarized: myeloid neoplasias comprising chronic myeloproliferative syndromes, myelodysplasic syndromes, an intermediate group called chronic myeloproliferative/myelodysplasic syndromes, acute myeloid leukaemia, lymphoid neoplasias comprising Hodgkin's and non-Hodgkin's lymphomas, either B or NK/T, histiocytic and dendritic cell neoplasias and finally mastocytosis. The different entities of each type are mentioned as well as, for the lymphomas, their frequency. This classification recommends a multidisciplinary approach for the diagnosis of each entity, comparing clinical and biological data, the results of cytological, histopathological and immunophenoypic studies as well as cytogenetics and molecular biology. In the future, comparative studies will be easier, due to the international use of this common language.