胃底腺領域の早期高分化腺癌の1例

Differentiated Carcinoma in the Fundic Gland Area, Report of a Case

要旨　患者は70歳，女性．過形成性ポリープの経過観察の目的で施行した上部消化管内視鏡検査で胃体上部大彎前壁寄りにⅡa＋Ⅱc型の3cm大の早期胃癌が発見された．胃X線所見で同部に比較的扁平な隆起性病変を認め，表面に不整形の陥凹を伴っていた．病変の大彎側と口側の部分は特に丈が低く，顆粒状の小隆起が集簱した部分を認めた．病理学的検索により粘膜下層深部まで浸潤した分化型癌であることが明らかになった．病変の辺縁や扁平顆粒部は非常に分化の良い腺窩上皮に極めて類似した癌組織から成っていた．背景粘膜は腸上皮化生を認めない胃底腺粘膜であった．粘液の組織化学的染色により癌細胞は腺窩上皮と同じ粘液組成であることが証明され，腺窩上皮型癌と診断した．体部腺領域の高分化腺癌の肉眼像・組織像はいまひとつ明らかでなく，その組織発生という点も含めて興味ある症例であると考えられた．

　Through endoscopic follow-up study of gastric hyperplastic polyp, a 70-year-old woman was diagnosed as having early gastric cancer, type Ⅱa+Ⅱc. Radiologically, the flat elevated lesion 30 mm in diameter with irregular depressed area was identified at the anterior wall along the greater curvature in the upper portion of the gastric body. In addition to his, some aggregated flat and granular lesions were seen at the edge of the tumor. Distal gastrectomy was performed. By histopathological examination, the tumor was shown to be a well differentiated carcinoma invading the deeper portion of the submucosal layer, and the background epithelium showed fundic-type mucosa without intestinal metaplasia. The aggregated flat and granular lesions were composed of extremely differentiated carcinoma resembling gastric foveolar epithelium. The mucosubst ance histochemistry of the carcinoma revealed Alcian blue (AB)(-), periodic acid Schiff (PAS)(+), galactose oxidase Schiff (GOS)(+) and paradoxical concanavalin A (Con A Ⅲ)(-). These results suggested that the tumor originated from the foveolar epithelium and could be classified as "foveolar type carcinoma".