拡大内視鏡による潰瘍性大腸炎関連腫瘍診断の現状と課題—初期病変を中心に

Current Status of Magnifying Colonoscopy for the Diagnosis of Intramucosal Neoplasia Associated with Ulcerative Colitis

要旨●潰瘍性大腸炎（UC）に慢性炎症を背景に発生するUC関連腫瘍（UCAN）は早期発見が容易でなく，特に初期病変である平坦型dysplasiaの内視鏡診断は困難と考えられてきた．しかし，近年，早期で発見される病変の増加とともに，平坦型を含めたUCAN，dysplasiaの拡大観察所見の蓄積・解析が進み，腫瘍・非腫瘍の鑑別，異型度診断が可能になりつつある．平坦型病変の発見のためには，粘膜模様の異なる領域，局所的な発赤領域などに着目し，境界を意識して拡大観察を加えることが重要である．

　UCAN（ulcerative colitis-associated neoplasia）originating from mucosa with active inflammation is difficult to detect at an early stage. However, with the recent increase in the number of UCAN lesions detected early, including flat lesions, it is becoming possible to differentiate between tumor and non tumor and to identify atypical degrees of dysplasia. To detect flat lesions, it is important to conduct a careful examination, focusing on areas with different mucosal patterns and locally reddened areas, using image-enhanced endoscopy with magnification.