Immunocytochemical methods in the study of lymphoma and related conditions.

The diagnosis and classification of malignant lymphomas is based upon traditional histological criteria evolved over the years by successive generations of pathologists. Immunoperoxidase methods applied to formalin paraffin sections have permitted a direct correlation of these established morphologic criteria with newer immunological concepts of the form and function of the B lymphocyte and its derivatives. Study of material from 500 cases of Hodgkin's disease, non-Hodgkin lymphomas, and myeloma has revealed that many of these conditions may find a common origin in the lymphocyte, and that some malignant cells, previously identified as malignant histiocytes or reticulum cells are rather related to or derived from the transformed lymphocyte or immunoblast. The corresponding tumors are thus more logically designated immunoblastic sarcoma. The study also reveals a claser developmental relationship between multiple myeloma and immunoblastic sarcoma than previously suspected, and suggests that all of the B cell lymphomas occur as part of a continuous spectrum of disease, rather than as separate entities as implied by current histological classifications. The study of immunoglobulin in formalin paraffin sections is illustrative of the great potential of this method in the diagnosis and study of neoplasia in general.