Small intestine & ampulla

Benign tumors / tumor-like conditions

Idiopathic retroperitoneal fibrosis



Last author update: 1 August 2012
Last staff update: 19 November 2020

Copyright: 2003-2024, PathologyOutlines.com, Inc.

PubMed Search: Idiopathic retroperitoneal fibrosis small bowel

Hanni Gulwani, M.B.B.S.
Page views in 2023: 926
Page views in 2024 to date: 263
Cite this page: Gulwani H. Idiopathic retroperitoneal fibrosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelIRF.html. Accessed March 29th, 2024.
Definition / general
  • Fibrosis which develops in retroperitoneum, often at aortic bifurcation
  • Associated with drug methylsergine, other fibrotic lesions (sclerosis of major bile ducts, Riedel thyroiditis, inflammatory pseudotumor of orbit)
  • IgG4 often involved in pathogenesis of idiopathic sclerosing lesion; associated with male gender
  • Associated with lymphoma, which developed in 15% of patients
Case reports
Gross description
  • Not well circumscribed
Microscopic (histologic) description
  • Widely scattered germinal centers and plasma cells in background of dense fibrosis
  • Eosinophilic infiltration and oblitertaive phlebitis in IgG4 related cases (Am J Surg Pathol 2009;33:1833)
Back to top
Image 01 Image 02