This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Ormond's disease is 
Select and explain. 
A. Retractile testis, B. Idiopathic retro peritoneal lymphadenopathy, C. Idiopathic retro peritoneal fibrosis, D. Idiopathic mediastinotis
C: Idiopathic retro peritoneal fibrosis
Answer: C: Idiopathic retro peritoneal fibrosis 
Explanation: In 70% cases of Ormond's disease Idiopathic retro peritoneal fibrosis is seen.