—胃型形質を示す胃上皮性腫瘍の内視鏡的特徴—腺窩上皮型腫瘍—一般型腺窩上皮型腫瘍

Endoscopic Findings of Conventional Gastric Foveolar-type Neoplasia

要旨●胃腺窩上皮型腫瘍は，胃粘膜を被覆する腺窩上皮細胞への分化を示す腫瘍細胞を主成分とするが，頸部粘液細胞（副細胞）への分化を示す腫瘍細胞が混在することもある．主にH. pylori未感染や除菌後の萎縮のない胃底腺粘膜領域に発生し，その内視鏡的特徴から，一般型，ラズベリー型に分けられる．一般型胃腺窩上皮型腫瘍の内視鏡所見は，白色光で白色〜同色調を示す平坦もしくは扁平な隆起性病変が多い．NBI併用拡大観察では，乳頭状・弧状・畝状の微小腺管構造を呈し，腺窩辺縁上皮の幅が広く，irregular microvascular patternを呈することが多い．本稿ではその内視鏡的特徴を解説し，一般型胃腺窩上皮型腫瘍とともに，鑑別疾患として腺窩上皮型過形成性ポリープ，多発性白色扁平隆起の自験例をそれぞれ提示した．

　GFTN（gastric foveolar-type neoplasia）is a tumor with cells that differentiate into foveolar epithelial cells, which cover the proper gastric mucosa, and mucus neck cells. It mainly occurs in the fundic gland mucosa without mucosal atrophy in naive or after Helicobacter pylori eradication. GFTN is classified into conventional and raspberry-like types based on endoscopic characteristics. Conventional type GFTN reveals the flat or flat-elevated shape and white to tonal on the white light image. Whereas, narrow-band imaging with magnification shows papillary, arcuate, or ridged microstructures, with wide marginal crypt epithelium and irregular microvascular patterns. This article describes the endoscopic features of GFTN and presents GFTN cases experienced in our institute. Moreover, foveolar hyperplastic polyps and multiple white and flat-elevated lesions are shown for comparison.