Abstract
This case report describes the novel use of infliximab as maintenance therapy for both Crohn disease and idiopathic retroperitoneal fibrosis in a patient with concurrent disease. A 34-year-old man with Crohn disease developed a pelvic mass and hydroureteronephrosis, leading to an idiopathic retroperitoneal fibrosis diagnosis. Given shared inflammatory pathways, he was treated with prednisone followed by infliximab. Post-treatment imaging showed mass reduction and hydronephrosis improvement. After 1 year, he remains stable. This case highlights infliximab's potential in managing both conditions, presenting a unique therapeutic approach. Further studies are needed to evaluate its broader application in dual pathology.