Idiopathic retroperitoneal fibrosis and ankylosing spondylitis. A new case report.

The case of a 52-year-old man with retroperitoneal fibrosis and ankylosing spondylitis is described. Inflammatory low back pain and acute renal insufficiency prompted a computed tomography scan of the abdomen with contrast agent injection. A fibrous sheath surrounding the aorta and attracting the ureters toward the midline was seen, strongly suggesting retroperitoneal fibrosis.