S4900 Novel Presentation of Extensive Gastric Oxyntic Metaplasia at the Ileocolic Anastomosis in a Crohn’s Disease Patient

Introduction: Gastric heterotopia and metaplasia are uncommon findings outside the upper gastrointestinal tract. While pyloric gland metaplasia is recognized as a sensitive indicator of chronic inflammation in Crohn’s disease (CD), oxyntic metaplasia is less frequently reported and to our knowledge, has not been previously described at the ileocolic anastomotic site. We present a novel case of extensive gastric oxyntic metaplasia at an ileocolic anastomosis found during routine surveillance in an asymptomatic patient with longstanding CD. Case Description/Methods: A 47-year-old man with a history of ileocolonic CD, diagnosed in the 1990s, presented for routine endoscopic dysplasia surveillance. He had previously undergone ileocolic resection during the initial disease course and remained in clinical remission without the need for maintenance therapy. His medical history was otherwise notable for incisional hernia repair with lysis of intra-abdominal adhesions in 2014. At the time of presentation, he was asymptomatic, reporting no abdominal pain or rectal bleeding, and had an unremarkable abdominal examination. On serial colonoscopies performed between August 2023 and April 2024, he had persistent, circumferential inflammation at the ileocolic anastomosis extending up to 15 cm into the neo-terminal ileum, with a Simple Endoscopic Score for Crohn’s Disease ranging from 4 to 6. Histology from the affected region demonstrated extensive oxyntic and pseudopyloric metaplasia without Helicobacter pylori. Additional biopsies demonstrated mild chronic active colitis in the transverse colon and rectum. Computed tomography enterography showed mucosal hyperenhancement and mild wall thickening in the neo-terminal ileum, consistent with active CD. Despite these findings, the patient remains clinically asymptomatic and is managed conservatively with ongoing surveillance. Discussion: This case represents the first known report of extensive gastric oxyntic metaplasia at an ileocolic anastomosis in a patient with CD. Recent studies have drawn attention to the role of gastric metaplasia as a potential precursor to nonconventional dysplasia in patients with inflammatory bowel disease, often preceding p53 mutations which are commonly associated with colorectal cancer progression. Further research is needed to determine the prevalence and clinical implications of gastric oxyntic metaplasia at the anastomotic site in CD and to explore its potential role as a marker of increased malignancy risk.