S6184 Stercoral Ileitis Mimicking IBD Flare in a Patient With End Ileostomy: A Mechanical Obstruction Masquerade

Introduction: Stercoral colitis is an inflammatory condition arising from fecal impaction, leading to colonic distention, pressure necrosis, and potential perforation. While well-documented in the colon, we propose the term Stercoral Ileitis to describe a similar process occurring in the ileum, particularly in patients with altered bowel anatomy such as long-standing ileostomies. This rare but important condition poses significant diagnostic challenges, as it can mimic Crohn’s disease and result in inappropriate immunosuppressive therapy. Case Description/Methods: A 57-year-old woman with ulcerative colitis (UC) status post-total colectomy and end ileostomy in 1988 presented with worsening abdominal pain, nausea, and decreased ostomy output. Computed tomography imaging showed fecalization and mural thickening of the terminal ileum at the stoma with proximal small bowel dilation, interpreted as partial obstruction. Ileoscopy revealed 5 clean-based ulcers with surrounding edema 5 cm proximal to the stoma. After temporary improvement with enemas, she rapidly redeveloped obstructive symptoms with worsening small bowel dilation on imaging and no clear transition point. Exploratory laparotomy revealed dense adhesions, a retracted stenotic stoma, and chronically dilated, friable bowel. A 6.5-hour adhesiolysis, small bowel resection, and stoma revision were performed. Histopathology showed mucosal ulceration, transmural edema, and ischemic changes localized to areas of chronic fecal stasis without granulomas or chronic architectural distortion, confirming Stercoral Ileitis. Discussion: This case illustrates a critical diagnostic pitfall in post-colectomy patients new-onset ileal inflammation near an ileostomy can mimic Crohn’s disease, especially in those with a prior history of UC. However, key distinguishing features include localized mural thickening, fecal impaction, absence of systemic symptoms, and lack of typical Crohn’s histology such as granulomas, transmural inflammation, or skip lesions. In this case, the inflammatory changes were confined to areas of mechanical obstruction caused by stool, supporting a diagnosis of Stercoral Ileitis. This condition is an underrecognized but important differential in post-surgical patients, as misclassification may lead to unnecessary immunosuppression and delay in definitive surgical management. A high index of suspicion, careful correlation of imaging, endoscopic, histologic, and clinical findings, and awareness of this entity are crucial for accurate diagnosis and appropriate treatment.