Endoscopic mucosal resection was carried out in a 70-year-old man with a ga
stric adenoma. Endoscopy 1 year later revealed a subpedunculated polyp abou
t 1 cm in diameter at the resection site. Pathological examination of the r
esected specimen showed hyperplasia of the regenerative epithelium. The mec
hanism of occurrence of hyperplastic polyp at the resection site is discuss
ed.