[Heterotopic gastric mucosa in the rectum: Report of a case]

Ectopic gastric mucosa has been described in different locations of the digestive tract, but that of the rectum is the least frequent.

The case is described of a 48 year-old woman being investigated by the gastrointestinal department due to rectal bleeding and rectal tenesmus. Colonoscopy showed a diverticular cavity 3 cm, which was reported by histology as fundic-type heterotopic gastric mucosa. Barium enema and abdominopelvic CT showed a diverticular image at level of the right posterolateral wall of the rectal ampulla. Trans-rectal diverticulectomy was performed with primary closure of the resulting mucosal defect. The surgical specimen showed areas of gastric epithelium with no signs of atypia.

It is not known whether the origin of heterotopic gastric mucosa occurs during foetal development or is the result of abnormal regeneration under inflammatory conditions. It is usually clinically asymptomatic or presents as haematochezia, especially in cases where gastric acid is being produced. In these cases there must be an initial treatment with proton pump inhibitors, although the definitive treatment is always surgical or endoscopic excision of the mucosa.