大腸通常型腺腫，腺癌の拡大内視鏡診断─鑑別診断

Differential Diagnosis for Colorectal Lesion

要旨●NBIと色素内視鏡拡大観察を併用することで，ほとんどの大腸病変に対してリアルタイムに鑑別診断を行い，治療方針を決定することができる．NBIの腫瘍・非腫瘍の鑑別能は色素撒布に匹敵するが，拡大内視鏡を併用することでより確信をもって診断することが可能である．癌・非癌の鑑別能も良好な成績が報告されている．しかし，NBI拡大観察には限界もあり，Tis/T1a癌とT1b癌の鑑別診断が必要な場合はクリスタルバイオレット染色による色素内視鏡拡大観察が必要である．

　A differential diagnosis of colorectal lesions can be easily made at a glance with magnifying NBI（narrow band imaging）without spraying a dye. Many authors reported that usefulness of NBI is equal to chromoendoscopy for differential diagnosis between neoplastic and non-neoplastic lesions. We recently reported an improved confidence in diagnosis of diminutive neoplastic colorectal polyp with magnifying NBI. Moreover, it is reported that magnifying NBI provides high accuracy for distinction between adenoma and cancer, but its diagnostic accuracy for assessing the depth of T1 colorectal cancer is inferior to that of magnifying chromoendoscopy using crystal violet dying.