Satoshi Kotani, Kotaro Shibagaki, Ryoji Kushima, Tsuyoshi Mishiro, Kenichi Kishimoto, Yusuke Takahashi, Norihisa Ishimura, Asuka Araki, Mamiko Nagase, Daisuke Niino, Shunji Ishihara
-naïve individuals with long-term proton pump inhibitor use. A syndromic form, resembling flat-type FGAs, is also associated with FAP and GAPPS. Histologically, FGPD features dysplasia confined to the superficial foveolar epithelium and mucus neck cells overlying fundic gland polyps, with APC mutations detected in approximately 50% of cases. This review explores the clinicopathological and molecular characteristics of HpNGNs with predominant foveolar cell differentiation, emphasizing the need for an updated histological diagnostic framework.