Retroperitoneal Fibrosis, also known as idiopathic retroperitoneal fibrosis, is related to sarcoidosis 1 and histiocytosis. An important gene associated with Retroperitoneal Fibrosis is MDM2 (MDM2 Proto-Oncogene), and among its related pathways/superpathways is Lung fibrosis. The drugs Prednisolone and Prednisolone acetate have been mentioned in the context of this disorder. Affiliated tissues include kidney and heart, and related phenotypes are immune system and respiratory system