Clinicopathological features of elevated lesions of the duodenal bulb. We present here our findings on patients with an elevated lesion of the duodenal bulb. All these patients were treated in our clinics between the years 1984 and 1988. These lesions were present in 36 of 8,802 patients who underwent upper gastrointestinal pan-endoscopy. Two patients had a duodenal carcinoma, 2 an adenoma, and 1 a Brunner's gland adenoma. There were 15 with a hyperplastic polyp, 3 with a heterogenic gastric mucosa, 3 with Brunner's gland hyperplasia, 6 with duodenitis, and 4 with regenerative mucosa. Among these 36 lesions, only 69% (25 lesions) were evident on the upper gastrointestinal X-ray series. Adenoma and Brunner's gland adenoma were of a pedunculated form of the gross type and had an irregular surface mucosa. Both duodenal carcinomas were detected by endoscopic biopsy and were resected. Histologically, these lesions were limited to the submucosal layer and were of the non-pedunculated polypoid form, but there were no other characteristic endoscopic features, in comparison with other elevated lesions. Thus, upper gastrointestinal endoscopy with routine observations of the duodenal bulb plus endoscopic biopsy will lead to a definite diagnosis of these elevated lesions and to the early detection and treatment of this rare malignant lesion. 