A practical approach to the diagnosis of Hodgkin lymphoma.

The diagnosis of Hodgkin lymphoma has become more difficult in recent years, paradoxically because of great strides made in the understanding of the molecular mechanisms driving the lymphomas. Extensive panels of monoclonal antibodies, coupled with flow cytometric analyses and molecular diagnostic studies, have served to define more lymphoma subtypes that cannot be identified based on morphologic evidence alone. This overview is intended to provide useful criteria for the recognition of Hodgkin lymphoma and to recommend tools that will aid in separating Hodgkin lymphoma from a series of common benign and malignant look-alikes. The relationships among Hodgkin lymphoma, the B-cell non-Hodgkin lymphomas, and the T-cell non-Hodgkin lymphomas are discussed, and useful immunohistochemical markers for the routine diagnosis of Hodgkin lymphoma are suggested.