粘膜下腫瘍様の小隆起を伴った陥凹型早期大腸癌の1例

Type Ⅱc Colonic Cancer with Submucosal Invasion, Report of a Case

要旨　患者は64歳，男性．注腸X線検査で，大きさ2.5×1.5cmの浅い陥凹性病変を描出し，内視鏡検査では，褪色調の粘膜を呈する陥凹部と，その口側に恒常性のある小隆起を認めた．帯域強調処理および超音波内視鏡検査を行い，Ⅱc型の粘膜下層浸潤癌と診断し，腸切除術を施行した，病理組織学的検討では，陥凹部は高分化型の粘膜内癌であり，小隆起部は粘膜下層へのわずかな癌の浸潤と，リンパ濾胞の増生と膿瘍の形成による構成であった．小隆起部はすべてが癌の浸潤ではなく，深達度診断を行ううえで，注意を要する形態であった．表面型早期大腸癌の浸潤を考えるうえで，興味深い症例であると考えられた．

　A case of type Ⅱc early colonic cancer in a 64-year-old male patient was reported. Barium enema disclosed a shallow depressed lesion, 2.5×1.5 cm in diameter in the descending colon. By colonoscopy, it was observed as a whitish shallow depression with a small elevated prominence. Image processing by band enhancement and endoscopic ultrasonography were performed, and the diagnosis of cancer with submucosal invasion was made. On operation was performed and the histological evaluation of the resected specimen revealed that the lesion was a well differentiated adenocarcinoma. The depth of cancer was mucosal except for the site of the elevated prominence where submucosal invasion was accompanied by the formation of lymph follicles and an abscess. The interest in this case lies in the mode of cancer extension in such superficial type colonic cancer.