1. Parietal cells in the proximal duodenum were first described by Kaufman in 1906' and noted to be close to Brunner's glands. Further studies have shown their prevalence in the duodenal bulb to vary, ranging from less than 1 %2 to almost 70%4 (table 1). Parietal cells were not found in the duodenum of the fetus and newborn, which suggests that they may be acquired.4 Most of these studies have described gastric heterotopia and not isolated groups of parietal cells in the duodenal bulb. Furthermore, there is some confusion in the literature regarding the difference between gastric heterotopia and gastric metaplasia in the duodenal bulb. The former refers to the presence of full thickness body-type gastric mucosa, and the latter, replacement of intestinal-type surface mucosa with gastric-type epithelium