The role of advanced atherosclerosis in idiopathic retroperitoneal fibrosis. Analysis of nine cases.

Idiopathic retroperitoneal fibrosis is an uncommon inflammatory disease characterized by a periaortic fibrous mass throughout the retroperitoneum that often surrounds the ureters, leading to ureteral obstruction. An immune-mediated process has been suggested in which the antigen is derived from atherosclerotic plaques. The optimal treatment of patients with idiopathic retroperitoneal fibrosis is unknown because of its rare occurrence. Surgery, medical treatment with immunosuppressive drugs, or a combination of both are proposed. In this retrospective study we report nine cases of idiopathic retroperitoneal fibrosis treated in our hospital. We quantitated the severity of atherosclerosis by measuring the degree of calcification in the aorta and compared this with a group of 19 age- and sex-matched controls without idiopathic retroperitoneal fibrosis. The idiopathic retroperitoneal fibrosis patients had a higher percentage of aneurysms of the abdominal aorta. However, abdominal aortic calcifications are not more prominent in idiopathic retroperitoneal fibrosis patients than in age-matched controls. These findings suggest that atherosclerosis as determined by abdominal aortic calcifications is not enough to provoke idiopathic retroperitoneal fibrosis. Furthermore, we evaluated the relapse rate of surgery versus medical treatment. In contrast to recent publications, no superiority of corticosteroids over surgical treatment could be demonstrated. However, our study is too small and retrospective. We estimate that a study which could find the most optimal treatment for idiopathic retroperitoneal fibrosis would need the participation of 40-50 medical centers each with a catchment population of about 200,000.