• A rare, serious disorder characterized by extensive fibrosis in the retroperitoneum. In most cases its etiology is unknown. In some cases it is related to autoimmunity or metastatic cancer. It leads to the entrapment and obstruction of vital retroperitoneal structures including the ureters.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• A slowly progressive condition of unknown etiology, characterized by deposition of fibrous tissue in the retroperitoneal space compressing the ureters, great vessels, bile duct, and other structures. When associated with abdominal aortic aneurysm, it may be called chronic periaortitis or inflammatory perianeurysmal fibrosis.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• (igg4-related retroperitoneal fibrosis) Retroperitoneal fibrosis (RPF) is characterized by the development of a fibrotic mass surrounding retroperitoneal structures, such as aorta, vena cava, ureters and psoas muscle.
  OrphaNet
  INSERM, 2021
• Retroperitoneal fibrosis (RPF) is characterized by the development of extensive fibrosis throughout the retroperitoneum, typically centered over the anterior surface of the fourth and fifth lumbar vertebrae and resulting in entrapment and obstruction of retroperitoneal structures, notably the ureters. See the image below.
  Medscape
  WebMD, 2019
• Retroperitoneal fibrosis is a slowly progressive disorder in which the tubes that carry urine from the kidneys to the bladder (ureters) and other abdominal organs or vessels become blocked by a fibrous mass and inflammation in the back of the abdomen. The disorder may cause pain in the abdomen that worsens with time, pain or swelling of...
  NIH Genetic and Rare Diseases
  National Center for Advancing Translational Sciences