colitic cancer/dysplasiaの内視鏡診断

Endoscopic Diagnosis of Colorectal Cancer and Dysplasia Associated with Ulcerative Colitis

要旨　最近の電子内視鏡の高画質化により，潰瘍性大腸炎に合併する早期大腸癌やdysplasiaの内視鏡診断が可能になってきた，慢性に経過する潰瘍性大腸炎には大腸癌の合併がみられ，surveillanceの重要性が指摘されている．surveillance colonoscopyは緩解期の患者を対象に十分な前処置のもとで行うのが望ましく，隆起性病変を見逃さないのはもちろんのこと，平坦な病変の拾い上げのために発赤・褪色調変化などの粘膜の色調の変化や表面構造の異常に注意することが大切と考えられる．潰瘍性大腸炎に合併する早期癌やdysplasiaにおいてもその多くは通常の早期癌，大腸腺腫に類似したpit構造を呈しており，色素撒布および拡大観察を併用することにより診断の精度が向上すると思われる．

　An increased risk of developing colorectal malignant lesions has been reported in patients with long-standing ulcerative colitis. In such patients, cancer surveillance is strongly recommended. High-resolution colonoscopy with magnifying observation is a useful method for detection of colorectal neoplastic lesions in such patients. Early carcinomas and dysplasia could be detected as flat elevated or plaque-like lesions with redness, discoloration, or surface irregularity. The pit structures obtained by magnifying observation in early carcinomas and dysplasia associated with ulcerative colitis are almost similar to those observed in ordinary colorectal neoplastic lesions. Given the inconspicuous endoscopic features of these early lesions, endoscopists should be aware of minimal changes in the mucosa during colonoscopic examination and consider magnifying observation with a dye spraying method.