微小胃癌診断のコツ―肉眼所見と対比して―内視鏡の立場から

Endoscopic Diagnosis of Minute Gastric Cancer

要旨　微小胃癌の内視鏡診断について，内視鏡所見と切除胃標本の肉眼所見および組織所見を対比し，小胃癌の所見とも合わせて検討した．微小胃癌64病変中27病変(42.2％)，小胃癌73病変中55病変(75.3％)を内視鏡および生検で術前に診断しえた．術前に診断しえた微小胃癌の40.7％は，切除標本で肉眼的に確認できず，微小胃癌全体では59.4％が確認できなかった．径3mm以下の微小胃癌の術前診断率は41％，3超～5mmでは44％であったが，3超～5mmになるとⅡb型を除き注意深い観察で診断は可能と思われた．術前に診断した小胃癌では切除標本上，ほとんど肉眼的に観察できたが，小胃癌全体では8.2％が肉眼的に確認できなかった．Ⅱa型微小胃癌の内視鏡所見は軽度の広基性隆起で，表面平滑で白色調のものが多く，小胃癌になると平盤状や半球状となり，表面に不規則な顆粒状凹凸やびらんを伴うことが多くなる．Ⅱc型では不整な陥凹の辺縁に，粗大顆粒状の凹凸を有する隆起を伴う所見が分化型癌の特徴と言えた。皺襞集中はないかあっても軽度で，小胃癌になると辺縁不整や辺縁隆起がより明瞭となり，陥凹面にも凹凸が認められることが多くなる．微小胃癌の内視鏡像と切除標本の肉眼所見は，おおむね対応するものであった．

　Concerning endoscopic diagnosis of minute cancer, endoscopic findings and macroscopic and histological findings of specimens of the resected stomachs were compared. At the same time, we considered findings concerning small cancers.

　Among 64 minute cancer lesions, 27 lesions (42.2％), and among 73 small cancer lesions, 55 lesions (75.3％) were diagnosed before operation by endoscopy and biopsy.

　In specimens of the resected stomachs, 40.7％ of the minute cancer lesions that were diagnosed before operation were unconfirmable macroscopically, and totally 59.4％ of all minute cancer lesions were unconfirmable.

　The preoperative diagnostic rate of minute cancers less than 3 mm in diameter was 41％. It was 44％ for minute cancers of 3-5 mm in diameter.

　It was felt that except for IIb type, careful observation made diagnosis of minute cancers of 3-5 mm possible.

　Almost all cases of the small cancers diagnosed before operation were confirmable by macroscopic inspection of specimens of the resected stomachs. Only 8.2％ of total number of small cancer lesions were unconfirmable macroscopically.

　In the case of IIa type minute cancers, the endoscope very often encountered the feature of mild elevation with smooth and whitish surface. However, in the case of small cancers flat semi-spherical shape with irregular convex-concave features and erosion were very often noticed.

　In IIc type minute cancers, elevation with rough, granular convex-concave features around an irregular depression was found to be characteristic of well differentiated adenocarcinoma. Convergence of folds wes absent or, if present, was slight in IIc type minute cancers. In small cancers, irregularities of the edges and elevation around the depression were seen clearly. There was a high frequency of convex-concave features on the surface of the depression.

　Endoscopic findings and macroscopic findings of resected specimens generally corresponded to each other.