内視鏡による早期胃癌のIIb進展範囲診断―クリスタルバイオレット染色による微細表面構造の拡大内視鏡観察の有用性

Usefulness of Magnifying Endoscopic Observation of Surface Micro-structure, in Order to Diagnose the Extent of IIb Type Early Gastric Cancer by Using Crystal-violet Staining

要旨　0IIb型早期胃癌の範囲診断において，クリスタルバイオレット染色による微細表面構造の拡大内視鏡観察の有用性を検討した．対象は微細表面構造観察後にESDを行った上皮性腫瘍226例（男175例，女51例，平均72.4歳）237病変，ならびにそのうちの0IIb病変4例，随伴IIbを有する2例で，（1）微細表面構造と病理組織所見との比較，（2）微細表面構造と肉眼型，粘液形質，（3）範囲診断，深達度診断における通常観察例との比較を行い，特に0IIbおよび随伴IIbを有した6例の微細表面構造の特徴を検討した．微細表面構造はTP，PP，DPの3型に，またTPはTP-L（Large and sometime branched）とTP-S（Small tubular or round）に分類された．以上の結果，PPおよびDPを除くM癌142病変中0IIa・0I・0IIb型56/67（83.6％）はTP-L，0IIc・0IIa＋IIc型72/75（96.0％）はTP-Sで，主にTP-Sは胃型，TP-Lは腸型の粘液形質を示した．また，DPは特にSM2癌では15/19（78.9％）であった．また，LM（－）は拡大観察で99.0％で，通常観察の85.2％に比し範囲診断能は向上した．一方，0IIbおよび随伴IIbを有する早期胃癌の微細表面構造は，6例全例でTP-S，TP-L（H）およびPPの混在が確認され，その複合所見を領域としてとらえることで正確な範囲診断が可能であった．以上から，微細表面構造の拡大観察は早期胃癌の診断，特に通常観察では困難な0IIb病変の範囲診断において有用であることが示された．

　Introduction : An accurate diagnosis of the tumor extent is very important in order to complete endoscopic submucosal dissection（ESD）successfully. We report the usefulness of magnifying endoscopic examination to perform accurate diagnosis of the tumor margin. Objects and Methods : The objects were 237 lesions of gastric tumor of in 226 patients（175 male,51 female, average : 72.4 years old）, which were resected by the ESD procedure. Among these cases, we encountered 6 cases of early cancer accompanied with 0IIb component. In this study, we evaluated the usefulness of magnifying endoscopic examination（Crystal-violet staining）of the surface micro-structure to diagnose the extent of the tumor. The surface micro-structures of gastric tumor were divided into three types（TP : Tubular pattern with irregular micro-structure,PP : Papillary pattern with irregular micro-structure,DP : Destructive pattern）, based on magnifying endoscopic finding and its stereomicroscopic view of the resected specimen. TP is a tubular or round shaped pit and PP is a papillary or villous shaped configuration. On the other hand,DP shows marked destruction of pit or surface structure. Results : In magnifying endoscopic examination of surface-microstructure,29 lesions（90.6％）of adenoma and 142 lesions（81.6％）of intra-mucosal cancer showed type TP significantly（p＜0.001）. Type DP was significantly observed in 19 lesions（61.3％）of submucosally invasive cancer. According to histological evaluation of the resected specimens, the magnifying endoscopic group revealed a significantly high rate of tumor negative in the lateral margin compared with the conventional group. On the other hand, magnifying endoscopy revealed composite findings of TP-S,TP-L（H）, and PP in all cases accompanied with IIb component（0IIb : 4,0IIa＋IIb : 1,0IIc＋IIb : 1）. Because of these findings, we were able to perform accurate diagnosis of the extent of cancer spread. Conclusions : Magnifying endoscopic observation（Crystal-violet staining）of surface micro-structure is thought to be very useful in the diagnosis of the tumor extent, especially in 0IIb type early gastric cancers.