食道表在癌の深達度診断―FICE拡大内視鏡の立場から

Diagnosis of the Invasion Depth of Early Esophageal Carcinoma Using Magnifying Endoscopy with FICE

要旨　FICEを併用した拡大内視鏡微による，食道表在癌の深達度診断の成績と問題点について，表在食道癌510病巣を対象として検討した．微細血管分類のtype 3を示す病巣の97.3％はhigh grade intraepithelial neoplasiaおよびpT1a-EP/LPM癌であったが，type 4を示す病巣にはpT1a-LPM癌～pT1b-SM癌まで含まれていた．type 3とtype 4SをpT1a-EP/LPM癌，type 4Mとard3をpT1a-MM/pT1b-SM1癌，type 4Lとard4をpT1b-SM2/SM3癌の診断規準とすると，pT1a-EP/LPM癌の診断率は96.0％，pT1a-MM/pT1b-SM1癌は81％，pT1b-SM2/SM3癌は97％，全体の正診率は490病巣中465病巣（94.9％）であった．AVAを形成しないtype 4Rは，20病巣中18病巣（90％）が低分化型扁平上皮癌や特殊な組織型，INFcの浸潤様式を示す病変に認められた．拡大観察による誤診の原因は，微小浸潤と表層が浅い癌で覆われながら，その深部に浸潤巣が認められる病変であった．

　We examined the results and problems involved in diagnosis of the invasion depth of superficial esophageal cancer on the basis of magnifying endoscopy obtained with FICE. A total of 510 lesions of superficial esophageal cancers were studied. 97.3％ of lesions with type 3 microvascular pattern were seen in high grade intraepithelial neoplasia and pT1a-EP/LPM cancer. type 4 vessels were obtained with pT1a-LPM and pT1b-SM cancers. When type 3 and type 4S vessels were considered the diagnostic criteria for pT1a-EP/LPM cancer, type 4M and ard3 vessels for pT1a-MM/pT1b-SM1 cancer, and type 4L and ard4 vessels for pT1b-SM2/SM3 cancer, the rate of correct diagnosis was 96.0％ for pT1a-EP/LPM cancer, 81％ for pT1a-MM/pT1b-SM1 cancer, and 97％ for pT1b-SM2/SM3 cancer. The rate of correct diagnosis for all cancers was 94.9％（465 of 490 lesions）. 18 of 20 lesions（90％）with type 4R vessels without formation of AVA were found in poorly differentiated carcinomas, specific histologic types of carcinoma, and lesions showing INFc infiltrative patterns. Misdiagnosis was caused by lesions with microinvasion and by tumors that were covered with shallow superficial layers of cancer cells, overlying deeper areas of invasive nodular foci.