Abstract: Objective: To investigate the clinical and CT features of idiopathic retroperitoneal fibrosis (IPF). Methods: 7 cases of retroperitoneal fibrosis proved by clinicopathology were presented. The clinical and CT performance of the cases were analyzed. There were 5 males and 2 females, with an average age of 53.5 years. All the cases were idiopathic fibrosis. Plain CT scan and contrast enhancement CT scan were undergone in all cases. Results: The clinical performances of the cases were nonspecific. The first symptoms included abdominal and lumbar pain. Others symptoms included lower extremity swelling (4 cases), abnormal soft-tissue mass (3 cases) and urinary tract obstruction (3 cases).On CT study, well circumscribed masses were showed in 7 cases. The lesions could be hypodensity, inhomodensity or isodensity, and various enhancements by contrast administration. Conclusion: Retroperineal fibrosis is a rare disease with various manifestations on CT study. It should be diagnosed if the mass lesion occurs in retroperitoneal space complicating with hydronephrosis or ureterolysis.

Key words: retroperitoneal fibrosis, Tomography, X-ray computed