NCI: A monoclonal B-cell lymphoproliferation in the vast majority of cases. It is characterized by a bimodal age distribution (15-30 years of life and late life) and is often associated with EBV infection. In less than 5% of cases it is a monoclonal proliferation of T-lymphocytes. Morphologically, it is characterized by the presence of Reed-Sternberg cells and mononuclear Hodgkin cells. The Reed-Sternberg and mononuclear Hodgkin cells are CD30 positive in nearly all cases and CD15 positive in the majority of cases.,NCI: The most common type of Hodgkin lymphoma, which is a cancer of the immune system. Classical Hodgkin lymphoma is marked by the presence of a type of cell called the Reed-Sternberg cell.