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Updated: Jun 19, 2026

Unilateral Ureteral Obstruction Model for Investigating Kidney Interstitial Fibrosis
Published on: April 25, 2025
Idiopathic retroperitoneal fibrosis: case report
Bartłomiej Kisiel1, Robert Kruszewski, Agnieszka Jurek-Urbanowska
1Department of Internal Diseases and Rheumatology, Military Institute of the Health Services, Warszawa, Poland. bartlomiejkisiel@wp.pl
Abstract:
A 45-year-old woman was admitted to the hospital because of abdominal pain, fever, and weight loss. Laboratory tests performed on admission revealed raised inflammatory markers. Ultrasonography of the abdomen showed dilatation of the pyelocalyceal system of the left kidney, while computed tomography showed retroperitoneal concentric periaortic mass extending to common iliac arteries and entrapping the left ureter. We established the diagnosis of idiopathic retroperitoneal fibrosis (RPF). JJ catheter was placed in the left ureter, and treatment with corticosteroids and azathioprine was started. Follow-up examinations showed a gradual improvement, namely a progressive remission of the retroperitoneal mass and normalization of both erythrocyte sedimentation rate and C-reactive protein concentration. Case reports, including our paper, and small case series showed azathioprine to be particularly effective in the treatment of RPF.