除菌後発見胃癌の病理組織学的特徴

Gastric Cancer Detected after Helicobacter pylori Eradication: Histopathological Features

要旨●除菌後発見胃癌を，H. pylori除菌治療成功後の胃粘膜に見つかった癌腫と仮に定義し，これに合致する31例34病巣とその周囲粘膜の病理組織像ならびに細胞形質について検索した．その検索結果は以下のように要約された．大きさ20mm未満の，胃腸混合型形質を有する，置換性発育型の高分化管状腺癌が多く，その細胞異型度は高低さまざまであった．また，粘膜内癌の表層には，腺窩上皮主体の形態・形質を示す非癌上皮が，種々の程度に不規則・モザイク状に介在していた．そして，癌巣周囲粘膜は，形質細胞主体の炎症細胞浸潤を伴った慢性萎縮性胃炎の組織像を呈し，胃腸混合型形質を有する不完全型腸上皮化生が目立った．以上の特徴の指摘とともに若干の病理組織学的考察を加えた．

　The aim of this study was to elucidate the histopathological features of gastric cancer detected after Helicobacter pylori（H. pylori）eradication. We studied 34 lesions from 31 patients with gastric adenocarcinoma（restricted to the mucosa or invading the submucosa：30 and 4 lesions, respectively）that were detected after successful H. pylori eradication. The results obtained were as follows. Gastric cancers detected after H. pylori eradication consisted of the replacing growth-type of differentiated carcinoma showing varied atypia with a mixed gastric and intestinal phenotype. The tumor size was mainly less than 20mm in diameter. Non-neoplastic epithelial cells expressing the gastric marker MUC5AC were often seen at the surface of the intramucosal differentiated carcinoma. The surrounding mucosa of the differentiated carcinoma contained scattered plasmacytes in the lamina propria mucosae and showed microscopic features of chronic inactive atrophic gastritis with mixed gastric and intestinal type intestinal metaplasia（corresponding to incomplete intestinal metaplasia）.