Rapid growth of a giant inflammatory polyp mimicking rectal malignancy in well-controlled Crohn's colitis: a diagnostic and therapeutic challenge.

Inflammatory pseudopolyps are a recognized complication of inflammatory bowel disease (IBD). However, their development in the context of well-controlled IBD is poorly understood. A 73-year-old woman with longstanding ileocolonic Crohn's disease that had been in endoscopic and histologic remission on sulfasalazine for 8 years developed a rapidly growing, fungating, ulcerated pedunculated rectal lesion, endoscopically indistinguishable from rectal carcinoma, within 1 year of a completely normal surveillance colonoscopy. An en bloc hot snare polypectomy confirmed an inflammatory pseudopolyp on histology, with no dysplasia or malignancy. She was subsequently escalated to vedolizumab after individualized consideration of her advanced liver disease and the agent's gut-selective mechanism, with sustained clinical improvement. This case highlights that quiescent IBD does not preclude alarming endoscopic findings, that inflammatory polyps can develop rapidly and mimic malignancy, and that even patients with apparent remission may have residual histologic disease activity. Pathologic evaluation remains indispensable, and such lesions should prompt reassessment of therapeutic adequacy.