Immunoblastic Lymphadenopathy: A Prelymphomatous State of Immunoblastic Sarcoma

Abstract

We became aware of the disorder, immunoblastic lymphadenopathy (IBL), during the course of our study of Hodgkin’s disease cases from World War II at the Armed Forces Institute of Pathology [6] when we were concerned with its resemblance to Hodgkin’s disease. A number of years were required to accumulate a sufficient number of acceptable cases of IBL with follow-up information to determine its clinical expressions and prognostic significance. The findings were presented finally at several meetings in 1973 [9, 10] and subsequently published as a series of 32 cases in early 1975 [11]. These cases collected from hospitals throughout the United States had been investigated clinically in a variable fashion, but nevertheless permitted the presentation of a rather distinctive clinical morphologic entity as a benign appearing hyperimmune proliferation of the B-cell system with distinctive morphologic features. It frequently was initially manifested by hypersensitivity reactions to therapeutic agents (35%), with a dramatic onset of fever, rash and pruritus, and later by generalized lymphadenopathy, and less frequently hepatosplenomegaly. Anemia was common and there was a consistent polyclonal hyperglobulinemia. A lymphoma of transformed lymphocytes, immunoblastic sarcoma (IBS), developed in the subsequent course of disease in three cases and justified consideration of IBL as a prelymphomatous disorder. We have now collected histologic material in over 250 cases of IBL and related disorders, approximately 100 of which fulfill the criteria we originally proposed for IBL; 25 of the latter cases have exhibited features of both IBL and IBS, either in subsequent specimens or in different areas of the initial biopsy. From this experience, it appears that there is a broad spectrum of as yet undefined abnormal immune reactions of which IBL represents the most extreme and abnormal component.