Heterotopic gastric mucosa of the gastrointestinal tract: a histopathologic study of 158 cases.

The author retrieved and retrospectively investigated biopsy specimens of heterotopic gastric mucosa registered in our computer database. There were 1008 cases affecting the esophagus, 684 cases affecting the duodenum, and 1636 cases affecting the colorectum. A total of 158 cases of heterotopic gastric mucosa were identified (84 cases affecting the esophagus, 74 cases affecting the duodenum, and no case affecting the colorectum). The frequency amounted to 8% in the esophagus, 11% in the duodenum, and 0% in the colorectum. The male to female ratio was 112:46, and the mean age was 62.22±14.29 years. Pathologically, two types of heterotopic gastric mucosa were identified. The first type consisted of gastric glands and foveolar epithelium, and the second type was composed only of foveolar epithelium. The first type was recognized in 69 of 84 cases (82%) in the esophagus, and in 54 of 74 cases (73%) in the duodenum. The second type was encountered in 15 of 84 cases (18%) in the esophagus, and in 20 of 74 cases (27%) in the duodenum. The first type appeared to be of congenital origin, while the second type was reminiscent of foveolar metaplasia. Foveolar hyperplasia and mild lymphocytic infiltration were frequent in the heterotopic gastric mucosa. Goblet cell metaplasia was recognized in 11 cases. The most frequent clinical diagnosis of heterotopic gastric mucosa of the esophagus was heterotopic gastric mucosa, followed in order by iodine-unstained area, reflux disease, flat elevation, polyp, carcinoma, ulcer, erosion, redness, submucosal tumor, esophagitis, adenoma, and tumor. The most frequent clinical diagnosis of heterotopic gastric mucosa in the duodenum was polyp, followed in order by ulcer, tumor, submucosal tumor, carcinoma, and duodenitis. The data suggest that esophageal gastric mucosa and duodenal heterotopic gastric mucosa are common lesions, with a frequency of about 9% in biopsy specimens in Japan.