Ulcerative colitis associated with gastric heterotopia in the rectum: a case report.

Gastric heterotopia is defined as the presence of morphologically normal gastric tissue at a non-physiological site, coexisting with the original tissue. Although it is not uncommon to see it in the esophagus, duodenum or small intestine, it is exceptionally rare to discover gastric mucosa in the rectum. Here we report the case of a 46-year old male with a 10-year history of ulcerative colitis in whom the surveillance rectosigmoidoscopy detected a Mayo score of 1 for ulerative colitis activity and a middle rectal sessile polyp. Pathological examination revealed an active chronic colitis, and rectal mucosa with heterotopic gastric mucosa composed of oxyntic glands was depicted. A month later, the patient was reevaluated and endoscopic mucosal resection was performed. Histology confirmed the gastric body type mucosa co-mingling with rectal mucosa.