[Transpyloric prolapse of a gastric carcinoma arising from a pedunculated hyperplastic polyp].

A case of gastric carcinoma developed on a large pedunculated hyperplastic polyp prolapsed into duodenum is reported. The cases of transpyloric prolapsed primary pedunculated gastric carcinoma are rare, only 34 cases have been described in Japan during the past 35 years, including the sessile forms. These gastric polyps should be considered in the differential diagnosis of intraluminar filling defects of the duodenal bulb. Endoscopy and biopsy are essential for a correct diagnostic evaluation. Large hyperplastic polyps, especially if prolapsed, require a surgical excision.