Idiopathic retroperitoneal fibrosis with functional duodenal obstruction.

Idiopathic retroperitoneal fibrosis with duodenal obstruction is a rarely reported clinical entity. The presenting symptoms of nausea, vomiting, weight loss, and progressive fatigability can be easily overlooked if attention is focused on the more prominent symptoms of low back and flank pain. Duodenal obstruction can present several months after the initial diagnosis of retroperitoneal fibrosis. Nutritional support before surgical correction is imperative.