Three other types of duodenal polyps: mucosal cysts, focal foveolar hyperplasia, and hyperplastic polyp originating from islands of gastric mucosa.

Seven cases are reported that initially presented on endoscopic examination as duodenal polyps originating from islands of gastric mucosa within the duodenal bulb. Microscopic examination revealed mucosal cysts (MC), focal foveolar hyperplasia (FFH), and hyperplastic polyp (HPP). These lesions must be added to the list of neoplastic and tumorlike lesions of the duodenum that may endoscopically present as polyps.