Idiopathic retroperitoneal fibrosis: clinicopathologic features and differential diagnosis

Kidney Int. 2007 Sep;72(6):742-53. doi: 10.1038/ Epub 2007 Jul 11.


Idiopathic retroperitoneal fibrosis (IRF) is a rare disease often causing obstructive uropathy. We evaluated the clinicopathologic features of 24 patients with IRF to characterize the histopathology of the disease and to provide a framework for the differential diagnosis with other retroperitoneal fibrosing conditions. Retroperitoneal specimens were analyzed by light and electron microscopy and by immunohistochemistry. Most patients presented with abdominal/lumbar pain, constitutional symptoms, and high acute-phase reactants. Overall, 20 had ureteral involvement and 13 developed acute renal failure. The retroperitoneal tissue consisted of a fibrous component and a chronic inflammatory infiltrate with the former characterized by myofibroblasts within a type-I collagen matrix. The infiltrate displayed perivascular and diffuse patterns containing lymphocytes, macrophages, plasma cells, and eosinophils. The perivascular aggregates had a central core of CD20(+) cells and a mantle of CD3(+) cells in equal proportions. In the areas of diffuse infiltrate, CD3(+) cells outnumbered the CD20(+) cells. Most plasma cells were positive for the IgG4 isotype. Small vessel vasculitis was found in the specimens of 11 patients. Our study indicates that a sclerotic background with myofibroblasts associated with a diffuse and perivascular infiltrate mainly consisting of T and B lymphocytes may be a pathological hallmark of IRF.

MeSH terms

  • Acute Kidney Injury / diagnostic imaging*
  • Acute Kidney Injury / etiology
  • Acute Kidney Injury / pathology*
  • Adult
  • Aged
  • B-Lymphocytes / pathology
  • Diagnosis, Differential
  • Eosinophils / pathology
  • Female
  • Fibroblasts / pathology
  • Fibroblasts / ultrastructure
  • Fibrosis
  • Humans
  • Immunohistochemistry
  • Macrophages / pathology
  • Male
  • Microscopy, Electron
  • Middle Aged
  • Plasma Cells / pathology
  • Retroperitoneal Fibrosis / complications
  • Retroperitoneal Fibrosis / diagnostic imaging*
  • Retroperitoneal Fibrosis / pathology*
  • T-Lymphocyte Subsets / pathology
  • Tomography, X-Ray Computed*
  • Ureter / diagnostic imaging
  • Ureter / immunology
  • Ureter / pathology
  • Urinary Tract Infections / complications
  • Urinary Tract Infections / diagnostic imaging
  • Urinary Tract Infections / pathology