Retroperitoneal fibrosis.

Retroperitoneal fibrosis, an uncommon and ill-defined condition, has a variety of causes and presenting features. The fibrotic process often produces ureteral obstruction and compression of surrounding structures. Pain in the flank, lower abdomen or lumbosacral region is the most common presenting symptom. Certain drugs, neoplasms, retroperitoneal injury or infections may all initiate the fibrotic process. This article describes a case of retroperitoneal fibrosis in a 34-year-old man who had been receiving a beta-adrenergic blocking agent.