Pathophysiology of Lymphocyte Transformation: A Study of So-called Composite Lymphomas

Abstract

The occurrence of two different histologic types of lymphoma in one organ, or in two different organs at the same time, or during the course of the disease, forms an intriguing biologic phenomenon. This report describes an immunohistologic study of ten such cases; seven consisting of two different non-Hodgkin’s lymphomas, together with three cases in which Hodgkin’s disease was one of the components. The findings in the non-Hodgkin’s lymphoma group are in keeping with emerging immunologic and physiologic concepts: i.e. , the different component parts appear to represent different maturation stages of the neoplastic B lymphocyte. The cases in which Hodgkin’s disease and a non-Hodgkin’s lymphoma were observed showed a surprising similarity between the malignant cells of both tumors when studied with immunoperoxidase technics for anti-light-chain and anti-heavy-chain antibodies. These observations may serve to resurrect an old belief in the common origin of certain of the non-Hodgkin’s lymphomas, and possibly also of Hodgkin’s disease. It is concluded from this study that true composite lymphomas are extremely rare and that the majority of the cases described as such are better considered as different morphologic expressions of a single malignant cell type—the lymphocyte.