Early symptoms:

• dull pain in the abdomen which increases with time
• swelling of one leg
• decreased circulation in the legs leading to pain and discoloration
• severe abdominal pain with hemorrhage due to ischemic bowel

Later symptoms:

• urine output, decreased
• total lack of urine (anuria)
• nausea, vomiting, changes in thinking caused by kidney failure and the resulting build up of toxic chemicals in the blood.

• elevations in serum BUN and creatinine
• kidney ultrasound may show hydronephrosis (distention of the kidney pelvis because of fluid accumulation) and a mass
• excretory urography may show compression and deviation of the ureters
• abdominal CT scan is the best test to reveal the retroperitoneal mass
• MRI offers comparable results to the CT scan
• biopsy to differentiate between retroperitoneal fibrosis and a cancerous tumor