During an investigation of the upper digestive tract of a 61-year-old female patient mainly complaining of hematemesis and melena, a peduculated polyp was discovered in the duodenum, and was surgically removed. Histologically, the polyp was recognized as a hamartomous polyp of Brunner's gland. Concerning the cases reported as so-called "Brunner's gland adenoma" it seems that there is a considerable difference in the histological findings between Japanese cases and Western experiences, and this point is discussed in this paper, referring mainly to our case and other cases reported in Japan
