[Hodgkin lymphomas: current understanding of pathogenesis and pathomorphology]

Brief summary of the history of Hodgkin disease as well as presentation of the current REAL/WHO classification of the Hodgkin lymphoma actually including two diseases entities is given. Beside the morphological, phenotypical and clinicopathological characterization of the classical as well as the nodular lymphocyte predominant Hodgkin lymphoma emphasis is placed on the differential diagnostics of the two basic types of Hodgkin lymphomas as well as on that of nodular paragranuloma versus nodular lymphocyte rich classical Hodgkin lymphoma. Summarizing the last decade's progress in research the current understanding of the pathogenesis of Hodgkin lymphomas is presented. The key elements of it is that although the tumor cells of both Hodgkin lymphomas arise from B-cells having passed the germinal center phase and exhibiting somatic hypermutation, the tumor cells of classical Hodgkin lymphoma do not have a functional immunoglobulin gene, but show a thorough phenotypic change, whereas the tumor cells of nodular paragranuloma preserve the B-phenotype and being under antigen selection pressure. The role of Epstein-Barr virus in the etiology is also introduced.