Rectal Mucosal Prolapse Syndrome: MRI and Endoscopic Images Mimicking Crohn's Disease.

Rectal mucosal prolapse syndrome (RMPS) is a rare condition that mimics Crohn's disease (CD) in imaging and endoscopy. We present a 29-year-old male with rectal tenesmus and a mid-rectal mass initially diagnosed as CD based on colonoscopy and MRI. After failed corticosteroid therapy, endoscopic resection revealed fibromuscular obliteration pathognomonic for RMPS. Chronic prolapse may induce secondary inflammation mimicking CD (including ulceration, stricture, and pseudofistulation), necessitating careful differential diagnosis to avoid unwarranted corticosteroid therapy.