陥凹性小胃癌の診断―NBIの立場から

Diagnosis of Small Depressed Type Gastric Cancer Using Magnifying Endoscopy Combined with Narrow Band Imaging

要旨　陥凹性小胃癌の診断における狭帯域フィルター内視鏡（narrow band imaging ; NBI）システムを併用した拡大内視鏡（magnifying endoscopy combined with NBI ; NBI-ME）の有用性について検討した．①通常拡大観察とNBI-MEでの表面構造および微細血管像の描出能の比較では，NBI-MEでより明瞭に認識されることが判明した（p＜0.001），②陥凹性小胃癌の典型的なNBI-ME所見は，明瞭な境界を有し，凹凸がなく，周囲より細かい模様の陥凹面であると考えられた，③分化度の違いによるNBI-ME像の違いを検討したところ，高分化型癌の72％でfine network patternを，未分化型癌の86％でcorkscrew patternを呈していた．NBI-MEは良悪性の鑑別や組織型の推定に有用であること，およびその限界が明らかになった．

　We evaluated the efficacy of magnifying endoscopy combined with narrow band imaging (NBI-ME) for small depressed type gastric cancer. ① We compared the visibility of NBI-ME and ordinary magnifying endoscopy (ME) for structure and vascular pattern of depressed-type gastric cancer. They could be recognized more clearly with NBI-ME image (p＜0.001). ② We investigated the typical NBI-ME findings of small depressed-type gastric cancer. They were the presence of a demarcation line, disappearance of surface structure and difference in gland size and pattern compared with the surrounding mucosa. ③ The NBI-ME findings of gastric cancer correlated well with the histological differentiation of gastric cancer. The fine network pattern was seen in well differentiated adenocarcinoma (72％) and the corkscrew pattern in undifferentiated adenocarcinoma (86％). We reported the efficacy and limits of NBI-ME for making a diagnosis of carcinoma and an estimation of differentiation from gastric cancer.