Idiopathic retroperitoneal fibrosis (M. Ormond). Review of current diagnostic and therapeutic concepts

Retroperitoneal fibrosis (RPF) is an uncommon inflammatory disease of the r etroperitoneum leading to extensive fibrosis with consecutive obstruction o f adjacent organs, namely the ureters. Since no consensus on the standard t herapy exists, the aim of this paper is to critically review the diagnostic and therapeutic concepts presented in the literature. Computed tomography (CT) and/or magnetic resonance imaging (MRI) are the pr eferred imaging procedures for diagnosis and follow-up after initiation of immunosuppressive therapy: periaortic fibrotic tissue masses exhibiting 30 to 50 HE are characteristic features of primary RPF on native CT scans. CT findings and pathohistology correlate very well: central areas of low, but constant, densities resemble fibrotic, avascular tissue, whereas peripheral regions with higher HE numbers resemble inflammatory, well vascularized ti ssues. MRI appears to be more sensitive than CT scans. T-1-weighted images exhibit masses isotense with the kidney and muscle. However, T-2-weighted i mages demonstrate higher signal intensities in the inflammatory stage of RP F, whereas the fibrotic stage is characterized by a decreased signal intens ity as compared to kidney and muscle. Initial therapy of primary RPF consists of endoluminal or percutaneous urin ary diversion to protect renal function followed by immunosuppressive thera py with prednison and/or azathioprin for at least 3 months. Follow-up CT fi ndings dictate the management thereafter: persistent acute inflammatory RPF should be treated by immunosuppressive combination therapy, whereas fibrot ic masses are best managed by a surgical approach. Surgical management of primary RPF should be initiated in the fibrotic stag e only. Ureterolysis and intraperitonealisation followed by a month course of adjuvant immunsuppressive therapy results in a continuous complete remis sion of more than 90%. Wrapping of the ureter with omentum maius is only re commended if wrapping is performed from the renal pelvis to the bladder. Re nal autotransplantation and ureteral ileal replacement are rarely performed nowadays and are only indicated in case of severe ureteral injury.