Introduction: Rectal gastric heterotopia (GHT) is extremely rare with less than eighty cases reported in the literature since it was first described by Ewell and Jackson in 1939. Two cases of malignant transformation have been reported, hence the need for resection. Most common methods of resection reported include surgery and endoscopic mucosal resection (EMR). Endoscopic submucosal dissection (ESD) for rectal GHT has been reported in few case reports in the literature. We present two cases of successful en-bloc resection with ESD of rectal GHT.

Case 1: A 45-year-old gentleman had colonoscopy for chronic alternating bowel habit with urgency and mucus discharge and intermittent abdominal pain. The index colonoscopy revealed an unusual 40 millimetres Paris IIa+IIc annular lesion in the low rectum. Optically this had elongated round and tubular pits. The histopathological examination of the biopsies revealed gastric type mucosa intermingled with adjacent colonic mucosa which led to the diagnosis of rectal GHT. He was referred to our centre for resection. ESD was performed with successful en-bloc resection and there was no evidence of significant fibrosis despite previous biopsies. The final histology confirmed R0 resection and revealed large area of specialised type gastric tissue, consistent with rectal GHT. Six months follow up endoscopy showed no signs of residual gastric heterotopia and patient was clinically asymptomatic with return of normal bowel habit.

Case 2: A 36-year-old male underwent colonoscopy in view of rectal bleeding, chronic intermittent abdominal pain and change in bowel habits. The index colonoscopy revealed a five centimetres Paris IIa lateral spreading tumour (LST) granular type polyp in the lower rectum with surface pattern of elongated round and tubular pits. The histopathological examination of the biopsies revealed a mixture of colorectal and gastric body-type mucosae in keeping with rectal GHT. He then underwent ESD which safely achieved en-bloc resection. There was no significant fibrosis seen but the submucosal plane was heavily vascular. The final histology confirmed R0 resection and showed large bowel mucosa intermingled with predominantly oxyntic and body pattern gastric mucosa which involved full thickness of the mucosa, consistent with rectal GHT. Patient had normalisation of symptoms during his subsequent follow-up. 

Conclusion: Rectal gastric heterotopia can be significantly symptomatic and ESD is a safe and effective resection modality to alleviate symptoms.