発赤調隆起型の胃底腺型胃癌（胃底腺粘膜型腺癌）の1例

Gastric Adenocarcinoma of Fundic-Gland Mucosa Type ; Reddish Protruded Type, Report of a Case

要旨●患者は60歳代，男性．胃体上部大彎前壁に胃底腺粘膜を背景に10mm大の発赤調隆起性病変を認めた．表面に拡張した樹枝状血管，辺縁に上皮下腫瘍様の隆起を認めた．NBI併用拡大観察では，微小血管構築像/表面微細構造ともにregularであり，非癌と診断された．生検結果と特徴的な内視鏡所見から胃底腺型胃癌と診断され，ESDを施行した．病理組織学的に，表層には腺窩上皮への分化を伴う低異型度の高分化腺癌と，その深部には胃底腺型腺癌を認め，胃底腺粘膜型腺癌と診断された．萎縮のない胃底腺粘膜を背景に，上皮下腫瘍様の隆起に加え，樹枝状の拡張血管，表面構造の軽微な変化を伴う隆起性病変を見つけた際には胃底腺型胃癌を疑い，生検を行う必要がある．

　The patient was a 60-year-old man with no history of Helicobacter pylori infection. A 10-mm-sized reddish protruded lesion was observed on the nonatrophic mucosa at the anterior wall of the greater curvature in the upper third of the gastric body. The lesion had dilated and branched vessels with a subepithelial shape on the surface. Due to regular microvascular and microsurface patterns on the lesion, it was diagnosed as noncancerous following magnifying endoscopy with narrow-band imaging. However, based on the biopsy results and the characteristic endoscopic findings, a GEN-FGML（gastric epithelial neoplasm of the fundic-gland mucosa lineage）was suspected. Therefore, we performed endoscopic submucosal dissection of the lesion. Histopathologically, tumor cells resembling gastric fundic gland cells were found in the deep part of the intramucosal layer up to the submucosal layer, and tumor cells resembling foveolar epithelium were found in the superficial mucosal layer. Therefore, this lesion was diagnosed as a gastric adenocarcinoma of fundic-gland mucosa type according to the immunohistochemical results. When a subepithelial lesion with dilated and branched vessels, color change, and surface structure change is detected in nonatrophic oxyntic gland mucosa, a biopsy should be performed to diagnose GEN-FGML.