炎症性腸疾患関連腫瘍—S状結腸に発生した平坦型潰瘍性大腸炎関連腫瘍の1例

A Case of Flat-type Ulcerative Colitis-associated Neoplasia Arising in the Sigmoid Colon

要旨●患者は40歳代，女性．発症から10年以上の経過を有する全大腸炎型の潰瘍性大腸炎患者．サーベイランスのための大腸内視鏡検査（CS）にて，S状結腸に5mm大の発赤調の丈の低い平坦隆起性変化を認めた．生検にて潰瘍性大腸炎関連腫瘍（UCAN）が疑われたため，当院へ紹介され受診となった．当院でのCSにてインジゴカルミン色素撒布観察を行うと，平坦隆起部には点状〜円状のインジゴカルミン液が貯留する粘膜変化が確認され，また同部に連続する形で周囲に同様の形態を呈する淡い発赤粘膜が確認された．同発赤部はインジゴカルミン色素撒布観察で境界明瞭となり，生検から同部もUCAN（low grade dysplasia）と診断された．範囲診断可能の判断のもと，同病変に対し内視鏡切除を施行した．最終病理組織学的診断はUCANであり，low grade dysplasia，Ly0，V0，pHM0，pVM0と診断された．

　A woman in her 40s with a 10-year history of pancolitis-type ulcerative colitis underwent surveillance colonoscopy（CS）, which revealed a 5mm, slightly elevated, flat, erythematous lesion in the sigmoid colon. The biopsy findings were suspicious for ulcerative colitis-associated neoplasia（UCAN）. The patient was referred to our hospital. CS with indigo carmine chromoendoscopy revealed mucosal changes characterized by pooling of indigo carmine in dot-/round-shaped areas within the flat, elevated portion. Mildly erythematous mucosa with similar morphology, continuous with this area, was also observed in the surrounding region. The borders of the erythematous area became clearly demarcated after spraying the indigo carmine dye, and biopsy specimens from the area led to the diagnosis of UCAN with low-grade dysplasia. The extent of the lesion could be determined by endoscopy, and endoscopic resection was performed. The final histopathologic diagnosis was UCAN with low-grade dysplasia（Ly0, V0, pHM0, pVM0）.