ABSTRACT
Introduction 587 Subclassification of Hodgkin lymphoma 587 Classical Hodgkin lymphoma 588 Immunohistochemical features of HRS cells in classical 588
Hodgkin lymphoma Nodular sclerosis Hodgkin lymphoma 589 Mixed cellularity Hodgkin lymphoma 589 Lymphocyte-rich classical Hodgkin lymphoma 589 Lymphocyte-depleted Hodgkin lymphoma 589 Nodular lymphocyte-predominant Hodgkin lymphoma 590 Differential diagnosis 590 Reactive conditions that may simulate Hodgkin lymphoma 590 Differential diagnosis between Hodgkin lymphoma and 591
other malignancies
Relations and possible combinations of Hodgkin 591 lymphoma and non-Hodgkin lymphoma
Cellular origin of HRS and LP cells 591 The lost B cell phenotype of HRS cells 592 Cell line models 593 Cytogenetic features of HRS and LP cells 594 Oncogenes and tumor suppressor genes 595 Epstein-Barr virus and other viruses in Hodgkin 596
lymphoma pathogenesis Activation of multiple signaling pathways in HRS cells 597 Antiapoptotic mechanisms in HRS cells 598 HRS cells in their microenvironment 598 Key points 599 References 599
In non-Hodgkin lymphomas (NHL) the predominance of the tumor cell population is one of the leading features, whereas in Hodgkin lymphoma (HL) the tumor cells are a minor population. It seems that interaction of the rare malignant tumor cells in HL with reactive cells modulates the surrounding tissue, induces a specific morphologic and immunohistochemical picture and triggers lymphoma growth. The diagnosis of HL has to be established by a pathologist who examines histologic sections showing the typical morphologic and immunohistochemical features of this disease. These features are:
● The lymphoid tissue contains scattered large mononuclear and multinucleated tumor cells, so-called Hodgkin and Reed-Sternberg (HRS) cells, which represent a minority compared with the cells in the surrounding tissue.
