P0448 - A Long Way From Home: Asymptomatic Heterotopic Gastric Mucosa Presenting as a Large Rectal Polyp

Erik Anderson, MD¹, Christina Steinhauser, DO², Patrick Young, MD^2
1Walter Reed National Military Medical Center, Washington, DC; ²Walter Reed National Military Medical Center, Bethesda, MD

Introduction: Heterotopic gastric mucosa (HGM) is the most reported epithelial heterotopia, most commonly seen in the esophagus, duodenum or within a meckel's diverticulum. Diagnosis of rectal HGM has increased over the last decade due to an increase in colonoscopy screening but remains rare.

Case Description/Methods: We present a case of a 48-year-old male without significant past medical found to have a 2cm rectal polyp on index screening colonoscopy after an episode of acute uncomplicated diverticulitis. The polyp was lifted with saline and removed in a piecemeal fashion using a 1.5cm hex snare and endocut. The residual edges of the polyp were removed using hot avulsion and the perimeter of the defect was treated with snare tip soft coagulation. The polyp was sent for evaluation and histology revealed heterotopic gastric mucosa. Repeat evaluation of the polyp site 6 months later showed no evidence of any residual polyp tissue.

Discussion: This case is a rare presentation of HGM. The prevalence of HGM is .1-11% in foregut and midgut but rarely hindgut. Symptoms are often non-specific and associated with acid production but there is no known association with diverticulitis. HGM can be asymptomatic in up to 19% of cases and in up to 24% of cases congenital malformations are also present.



Treatment can be medical, targeting acid reduction, or resection. Resection is preferred when there is an associated fistula, rectal duplication or ulcerative morphology. The potential of HGM in the rectum to transform into a malignancy is relatively unknown, although there are at least 3 reports documenting intestinal metaplasia and adenoma. There also have been reports of malignant transformation of HGM in the esophagus. Currently there are no guidelines for the management of HGM, but endoscopic or surgical resection presents the best option for symptom management and reduction of risk of malignant transformation.


Disclosures:
Erik Anderson indicated no relevant financial relationships.
Christina Steinhauser indicated no relevant financial relationships.
Patrick Young indicated no relevant financial relationships.


Erik Anderson, MD¹, Christina Steinhauser, DO², Patrick Young, MD². P0448 - A Long Way From Home: Asymptomatic Heterotopic Gastric Mucosa Presenting as a Large Rectal Polyp, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.