Concepts of lymphoma classification.

Three major classification schemes for malignant non-Hodgkin's lymphomas are widely applied today: Rappaport's classification, the Kiel classification, and the New Working Formulation for Clinical Usage. All three classifications define prognostically relevant lymphoma entities yet can only partly be translated one into the other. This is because morphologically defined lymphomas still include certain inhomogeneic entities, which again applies to all three classifications. It is therefore strongly suggested that supplemented morphologic methods of lymphoma classification be by immunologic and cytochemical investigations to improve on the scientific definition of malignant lymphomas and also to obtain the most solid basis for therapeutic planning.