S4862 Mucosa Building Bridges: An Uncommon Cause of Colonic Obstruction in Ulcerative Colitis

Introduction: Mucosal bridging (MB) is a unique phenomenon associated with a variety of inflammatory conditions of the gastrointestinal tract. These mucosal projections within the gastrointestinal lumen can lead to complications such as dysphagia, pain or obstruction. While MB is already considered an uncommon finding in inflammatory bowel disease patients, colonic MB in patients with ulcerative colitis (UC) is considered particularly rare. Case Description/Methods: A 50-year-old man with a past medical history of untreated UC complicated by strictures requiring left hemicolectomy in 2018, recurrent Clostridioides difficile infections, untreated chronic hepatitis C and polysubstance use presented with a 2-day history of progressive abdominal pain, nausea, vomiting, and constipation. Laboratory evaluation was unremarkable, with no leukocytosis, normal inflammatory markers and negative Clostridioides difficile infections testing. Imaging demonstrated distended loops of small and large bowel, and abdominal CT identified a distal colonic mass at the site the surgical anastomosis. Colonoscopy revealed a circumferential pseudopolyp at the anastomosis contributing to the obstruction. Further examination of the distal colon using pediatric colonoscope showed extensive pseudopolyps and multilobulated diverticula consistent with mucosal bridging. Histologic examination of cecal biopsy demonstrated inflammatory changes with focal cryptitis suggestive of UC. The patient’s symptoms resolved following endoscopic decompression, and no surgical intervention was required. The patient was discharged with follow-up arranged with gastroenterology for outpatient UC management. Discussion: Colonic mucosal bridging is an uncommon and underrecognized manifestation of UC. Previous reported cases often occurred spontaneously and were discovered incidentally—such as during surveillance colonoscopy or during an acute flare in a patient considered to be in remission. One case did document MB formation a year after sigmoid resection with colo-colonic anastomosis in a patient with active UC. Although MB formation rarely progresses to the severity seen in our case, it is worth considering that patients with undiagnosed or untreated UC may develop subclinical MB. While initially asymptomatic, such anatomical changes to the gut lumen could predispose them to future complications and may necessitate more frequency follow up. Awareness of this potential complication is essential when guiding management and surveillance strategies in inflammatory bowel disease patients.