Focal Intramucosal Adenocarcinoma Occurring in Gastric Hyperplastic Polyps Treated with Endoscopic Mucosal Resection.

Hyperplastic polyps are the most frequent benign epithelial gastric polyps. Although they are considered nonneoplastic, some cases have been reported with focal adenocarcinoma. We present the case of a 59-year-old woman with a sessile lesion of 15 mm on the distal gastric body associated with an extensive atrophic gastritis. Magnifying endoscopy with Fuji Intelligent Color Enhancement (FICE) revealed an irregular microsurface pattern at the apex, suggesting malignancy. A mucosectomy was performed. The histopathology revealed that the base corresponded to a hyperplastic polyp, where a tubular adenoma with high-grade dysplasia was established, with focal well-differentiated intramucosal tubular adenocarcinoma.