The occurrence of vasculitis in perianeurysmal fibrosis.

The histological findings of retroperitoneal fibrosis in 17 operated patients are described. Of these patients 6 showed a simultaneous aneurysm of the abdominal aorta verified either by computerized tomography, ultrasound, arteriography or during an operation. Of the patients 14 were operated on primarily because of ureteral obstruction, 2 because of aortic aneurysm and 1 because of rupture of the abdominal aorta. Advanced fibrosis with varying amounts of inflammation was detected in all 17 patients. The same histological pattern was present in patients with aneurysm of the abdominal aorta and in those without aneurysm. Accompanying vasculitis with destruction of the vascular wall was noted in 8 patients, including 6 with an abdominal aortic aneurysm. In 3 patients who underwent aneurysm resection as well as in 1 patient with aortic rupture the process extended into the aortic wall. The only patient with vasculitis and no aortic process suffers from severe rheumatoid arthritis. On the basis of the different histological findings we suggest that retroperitoneal fibrosis with vasculitis and aneurysm may represent a distinct pathological entity.