A case of gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS)

Abstract

　Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is an autosomal dominant hereditary disease characterized by massive and potentially malignant polyposis of the gastric body and fundus, which has been described in 2012. Herein, we report a case of GAPPS that was successfully diagnosed based on genetic testing.

　A 44-year-old Japanese woman had a family history of her mother of gastric polyposis which disappeared without any treatment at her 30s and developing multiple fundic gland polyps after treatment of gastric cancer at the age of 73 years. Thus, esophagogastroduodenoscopy was performed which revealed polyposis limited to the greater curvature of the stomach. Additionally, whitish protuberances that differed from the other polyps were resected and histopathologically diagnosed as gastric adenocarcinoma. GAPPS was suspected and confirmed by the presence of a point mutation at the APC gene’s promoter 1B site on genetic testing. Since GAPPS is a relatively new disease-concept with limited reports on it, its clinical management, including prophylactic total gastrectomy and surveillance, remains unknown owing to insufficient evidence. Therefore, careful follow-up and continued genetic counseling are crucial.