A case of end-stage renal failure caused by renal amyloidosis of the AA type is reported. No chronic disease responsible for the deposition of reactive amyloid was detected until giant lymph node hyperplasia of the angiofollicular type was identified in a mediastinal mass. Amyloid was found within the tumour mass and was characterized by immunochemistry with monoclonal antibodies to be of the AA type. Castleman's disease should be added to the list of chronic diseases endangering renal function by inducing the production and tissue deposition of secondary (AA) amyloid.