Severe back and abdominal pain in a 44-year-old woman.

Retroperitoneal fibrosis is an uncommon collagen vascular disease. Back pain with no specific radiation pattern is a common finding. Evaluation usually begins with an abdominal CT scan or MRI. The finding of fibrous periaortic tissue in conjunction with an elevated erythrocyte sedimentation rate supports the diagnosis. A biopsy is necessary to confirm the diagnosis and exclude malignancy. Sometimes retroperitoneal fibrosis can progress to the point of causing bilateral ureteral obstruction leading to acute renal failure. Corticosteroids, in conjunction with surgery when needed, are the mainstay of therapy.