Heterotopic gastric mucosa (HGM) in the rectum is an extremely rare clinical entity which may be missed or misdiagnosed due to a lack of knowledge. In the present study, a 14-year-old girl visited our hospital due to a 5-year history of repeated hematochezia. Colonoscopy showed a solitary superficial depressed lesion approximately 5 cm in size and a concomitant 1.5 cm deep diverticulum in the rectum. Histological examination of the endoscopic biopsy showed typical ectopic gastric mucosa in the depressed lesion and inside the diverticulum. Narrow band imaging further confirmed the histological results. Endoscopic ultrasound indicated that the lesion originated from the mucosal layer, and partially involved the submucosal layer. Endoscopic submucosal dissection was performed in this patient due to the large size and shape of the lesion. No bleeding, perforation or other adverse events were observed. The presence of HGM in the diverticular cavity greatly increased the surgical difficulty. A literature review was also carried out in our study.
Keywords: Endoscopic submucosal dissection; Endoscopy; Helicobacter pylori; Heterotopic gastric mucosa; Rectum.