陥凹型を呈した早期大腸乳頭腺癌の1例

Papillary Adenocarcinoma of the Depressed Type of Early Colorectal Cancer, Report of a Case

要旨　患者は60歳代，男性．検診で便潜血陽性を指摘され近医で下部消化管内視鏡を施行され，大腸に病変が認められ，精査・加療目的で紹介となった．当院での内視鏡所見では盲腸に径12mm大のIIc＋IIa様の病変が認められた．拡大観察では病変の辺縁は不整な管状腺管，中心部はうろこ状，乳頭状の構造が認められた．判断に苦慮したがSM深部以深浸潤の所見ではないと診断しEMR（endoscopic mucosal resection）を施行した．本病変の病理診断は腺腫内癌．癌成分：乳頭腺癌 ; 深達度SM1（800μm），ly0，v0．腺腫成分：中等度異型度との診断であった．乳頭腺癌で陥凹型の形態をとる病変は非常にまれと考え，腫瘍の発育進展を考えるうえで興味深い症例であった．

　A man in his sixties visited our hospital with a diagnosis of colorectal polyps. Colonoscopy findings showed multiple polyps and a depressed lesion, type IIc＋IIa, 12mm in diameter in the cecum. Magnifying colonoscopy showed irregular pits at the margin of the depressed area and fish-scale shaped and, papillary shaped structures in the center of the depressed area. We diagnosed it to be depressed type early colorectal cancer（M）. Endoscopic mucosal resection was performed. Pathologically, the tumor was a papillary adenocarcinoma with an adenomatous component, SM1（800μm）, ly0, v0. This is a very rare case of papillary adenocarcinoma of the depressed type of early colorectal cancer.