RENAL THROMBOTIC MICROANGIOPATHY ASSOCIATED WITH MULTICENTRIC CASTLEMANS-DISEASE - REPORT OF 2 CASES

Castleman's disease (also called giant lymph node hyperplasia or angio follicular lymph node hyperplasia) is a clinicopathological entity of unknown etiology. Two histologic patterns of lymph nodes are classical ly recognized: the hyaline-vascular and plasma-cell variants. Recently , multicentric Castleman's disease has emerged as a separate clinical entity manifested primarily by generalized lymphadenopathy and systemi c manifestations, such as thrombocytopenia, hemolytic anemia, hepatosp lenomegaly, altered liver function tests, central nervous system alter ations, and autoimmune manifestations. A number of renal alterations h ave been described in association with the two pathological variants o f Castleman's disease, but thrombotic microangiopathy has been previou sly reported only once in a patient with Castleman's disease, No renal biopsy was performed in that patient, although there was evidence of renal dysfunction. We report two cases of biopsy-proven renal thrombot ic microangiopathy associated with multicentric Castleman's disease. I n addition to having lymph node pathology characteristic of Castleman' s disease, both patients presented with generalized lymphadenopathy an d systemic manifestations, including acute renal failure, hypergammagl obulinemia, anemia, thrombocytopenia, and hypoalbuminemia. Autoantibod ies were present in both patients, including antiphospholipid antibodi es in one patient. The renal biopsies, examined by light, immunofluore scence, and electron microscopy, were diagnostic for renal thrombotic microangiopathy. The simultaneous development of two rather uncommon s yndromes, multicentric Castleman's disease and renal thrombotic microa ngiopathy, suggests a possible link between Castleman's disease and re nal thrombotic microangiopathy. Furthermore, we propose that the produ ction of autoantibodies, in particular antiphospholipid antibodies, ma y lead to the development of thrombotic microangiopathy in some patien ts with multicentric Castleman's disease.