An Unusual Case of Heterotopic Gastric Mucosa Followed for 5 yrs

Abstract

Heterotopic gastric mucosa is either a result of abnormal differentiation of fetal endoderm or a metaplastic process from regeneration of local mucosa. It can occur throughout the GI tract, most commonly in the esophagus and meckels diverticulum. Review of literature suggests duodenal heterotopic gastric mucosa is fairly rare, usually associated with an ulcer and ranges in size from 3 mm to 10 mm. Here we illustrate a case of a duodenal heterotopic gastric mucosa not associated with an ulcer measuring 40 mm. An 89 yr old caucasian male, was admitted for constipation and anemia. Pertinent positive findings on physical examination was a positive stool hemoccult on digital rectal examination. Lab data showed Hb-11.9 mg/dl. CT of the abdomen and pelvis was negative for any pathology. EGD revealed 40 mm sessile polyp in the duodenal bulb with an associated esophageal ulcer, hiatal hernia, atrophic gastritis and grade III esophagitis. Multiple biopsies were taken but the polyp was not removed. The pathological report showed heterotopic gastric mucosa. Interestingly, approximately 5 years ago this patient underwent EGD which reported a flat sessile soft villous 10 mm polyp in the duodenal bulb. Biopsy report was the same. The pathogenesis of gastric gland heterotopia is controversial. Some investigators advocate a theory of secondary invasion of the surface mucosa through a defect in the muscularis mucosa, arising as a result of inflammation or ulceration, others insist on a congenital origin based on cases in which no microscopic signs of muscularis mucosal injury or inflammatory cell infilteration of the mucosal layer were demonstrable. Experimental evidence suggests that downward adenocystic proliferation of glands is a dysplastic or a precancerous change. Histology shows normal gastric mucosa including mucinous tall columnar epithelial cells, as well as chief and parietal cells below the gastric glands, just in an abnormal location. Complications include obstruction, peptic ulceration, hemorrhage and perforation. There is no reference in medical literature to malignant transformation of heterotopic gastric mucosa. Endoscopic resection, surgical resection and observation by periodic EGD have all been suggested for a follow up and differential diagnosis. To our knowledge, this is the largest polypoid heterotopic gastric mucosa in the literature and the patient was followed for 5 yrs. with significant increase in the size of the mucosa from 10 mm to 40 mm with no change in histopathology. Pictures of endoscopy will be presented.