colitic cancer/dysplasiaの早期診断―通常内視鏡診断

Conventional Endoscopic Diagnosis ofColitic Cancer and Dysplasia

要旨　潰瘍性大腸炎（UC）の長期経過例では，dysplasiaやcolitic cancerが発生する危険性が高まる．大腸内視鏡（CF）でUC関連腫瘍を早期発見するためには，内視鏡所見の特徴を把握しておく必要がある．当院で経験したUC関連腫瘍の中で，CFで病変部位を認識できたdysplasia 23病変と進行癌を除くcolitic cancer 9病変を対象とした．UC関連腫瘍を発見する契機となった内視鏡所見は病変部の隆起が22病変（69％）を占め，特にcolitic cancerで多かった．また平坦な病変は，限局した発赤や粘膜面の凹凸不整で発見されていた．UC関連腫瘍の肉眼型は隆起型が高頻度で，特にcolitic cancerは表面が結節状を呈する病変が多かった．なお，平坦型はdysplasiaの7病変（30％）に認められた．腫瘍の色調は不均一な発赤を呈する場合が多く，半数の病変は周囲との境界が不明瞭であった．UC関連腫瘍を疑う内視鏡所見を認めた際には色素撒布も併用し，病変の存在を確認するとともに表面構造の詳細な評価を行う必要がある．

　Patients with ulcerative colitis（UC）are at high risk for dysplasia and colitic cancer as can be seen during long-term follow-up. The early detection of UC-related neoplasm by colonoscopy requires an understanding of the characteristics of the endoscopic findings of these lesions. Among UC-related neoplasms treated in our hospital, we studied 23 lesions of dysplasia and 9 lesions of colitic cancer diagnosed by colonoscopy, excluding advanced cancer. The most common endoscopic finding leading to the detection of UC-related neoplasm was an elevated lesion for 22 tumors（69％）, especially in colitic cancer. Flat lesions were detected in the areas with localized redness or an uneven surface of the mucosa. As for macroscopic appearance, a high proportion of UC-related neoplasms were elevated lesions. In particular, colitic cancer was frequently associated with nodular lesions. Seven lesions of dysplasia（30％）were flat lesions. As for tumor color, many lesions showed uneven redness. About half of the lesions were poorly demarcated. Lesions suspected to be UC-related neoplasms on endoscopic examination should be carefully evaluated after the application of dye to confirm the presence of lesions and to assess the surface structure in detail.