Immunoblastic lymphadenopathy. A hyperimmune entity resembling Hodgkin's disease.

Immunoblastic lymphadenopathy, although it resembles Hodgkin's disease, is a distinct, hyperimmune disorder apparently of the B-cell system. In 32 cases, it was characterized by a morphologic triad: proliferation of arborizing small vessels; prominent immunoblastic proliferations; and amorphous acidophilic interstitial material. Clinically, it is manifested by fever, sweats, weight loss, occasionally a rash, generalized lymphadenopathy and often hepatosplenomegaly. There is a consistent polyclonal hyperglobulinemia and often hemolytic anemia. The course of the disease is usually progressive, with a median survival of 15 months in 18 fatal cases. The cellular proliferation appears benign morphologically in the pretherapy biopsies and in 10 of 12 available autopsy cases. In three cases the process evolved into a lymphoma of immunoblasts, immunoblastic sarcoma. The basic process appears to be a non-neoplastic hyperimmune proliferation of the B-cell system involving an exaggeration of lymphocyte transformation to immunoblasts and plasma cells that may be triggered by a hypersensitivity reaction to therapeutic agents.