Histopathology of Hodgkin's lymphoma.

In the last few years, there has been a greater understanding of the spectrum and biology of Hodgkin's lymphoma. In standard texts, Hodgkin's lymphoma is classified as 2 distinct entities, namely nodular lymphocyte predominant Hodgkin's lymphoma and classical Hodgkin's lymphoma. However, recent evidence suggests that classical Hodgkin's lymphoma is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes may be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis Hodgkin's lymphoma, particularly those cases presenting with mediastinal disease, also seems related to primary mediastinal B-cell lymphoma. As Hodgkin's lymphoma is a B-cell neoplasm, there is also a better appreciation today of cases that may be borderline with conventional B-cell lymphomas. We present an update on the histopathological features of Hodgkin's lymphoma and the immunohistochemical tools available for diagnosis in the clinical setting.