色素による内視鏡検査法―早期胃癌を中心に

Dye Scattering Method in Endoscopy for Diagnosing Early Gastric Cancer

　近年の消化管内視鏡診断学の進歩は目覚しく，教室でも今日までに264例の早期胃癌を経験しており，早期胃癌の内視鏡診断に日常困難を感ずることは少くなった．もちろん，癌浸潤範囲や深達度の診断，あるいは胃粘膜面の形態変化が軽微な平坦型早期胃癌や微小胃癌の把握など，より精細な病変の内視鏡診断にはいまだ問題が残るが，この解決法の一つとして拡大内視鏡などの器種の改良とともに，内視鏡的色素撒布法が注目され，胃内視鏡診断学の中で新しい展開がなされてきたのである．すなわち，色素撒布法は胃粘膜表面の粘液を処理することに成功^1)～3)して以来，通常内視鏡検査では観察できなかった胃粘膜面の微細な凹凸性変化を描出できるようになり，正常胃粘膜の胃小区単位の検討⁴⁾⁵⁾を経て，本法が各種胃疾患に応用され，形態学的な内視鏡診断能の向上ばかりでなく，さらには病態の機能を応用した内視鏡診断へと変遷しているのである^6)～10)．早期胃癌への内視鏡診断は癌病巣と周辺非癌性粘膜の識別，さらには通常内視鏡検査では診断不能なⅡb型早期胃癌診断へといくつかの新しい知見が加えられた^10)～12)．本文では内視鏡的色素撒布法の概略を述べるとともに，早期胃癌の診断に対する本法の有用性とその応用についてふれてみたい．

　A survey is made of endoscopic dye scattering method and vital staining method both effective for the diagnosis of early gastric cancer. Dye scattering method with indigo-carmine enables one to clearly observe fine unevenness of the gastric mucosa and to detect abnormal findings of a cancerous lesion. In the case of depressed type of early cancer, interpretation of abnormal findings becomes especially easier not only in delineating the canerous margins, but also in observing abnormal redness and abnormal granules of the mucosal surface. More accurate determination of the circumference of cancerous lesion or of the depth of cancerous invasion becomes thus possible.

　Vital staining method with methylene blue shows that the intestinal metaplasia of the gastric mucosa has stainability, while the area of cancer lesions is generally hard to stain. Difference in dyeing in this method can be applied not only to diagnosis of gastric cancer but also to the determination of the borders of cancer infiltration.

　By endoscopic dye scattering method it become possible to discriminate minutely the nature of non-cancerous mucosa around a lesion. A picture obtained by indigo-carmine scattering procedure would indicate in what glandular area a cancerous lesion is located. In vital staining method with methylene blue it become easier to recognize an intestinal metaplasia around the cancerous mucosa, and to determine its forms and distributions. Determination of the margins of cancer infiltration is made easier by it along with that of depth infiltration inferred by the histologic type of a cancer lesion. This method can be a powerful weapon in the diagnosis of Ⅱb type of early gastric cancer that would be often overlooked by an usnal endoscopy.

　Dye scattering method is thus in a position of precise endoscopic examination supplementing the usual endoscopy.