小さな大腸pm癌の1例

Small Colonic Cancer Invading the Muscularis Propria, Report of a Case

要旨　患者は58歳，男性．主訴は排便回数の増加．一般検査では便潜血反応Latex法（＋）以外はCEAを含め異常なし．大腸X線検査では，腹臥位二重造影法と圧迫法にて，横行結腸中部の前壁寄りに，中央に淡いバリウム斑を伴う楕円形の平盤状病変を認めた．内視鏡検査では，中心陥凹を有し，隆起の起始部粘膜が正常な平盤状病変で，Ⅱa＋Ⅱc型大腸癌と診断した．手術にて，16×12mmの小さなⅡa＋Ⅱc様の病変で，病理学的には癌の粘膜下浸潤により平盤状に隆起した病変であり，隆起の起始部粘膜は正常だった．癌の組織型は高分化型腺癌であったが，浸潤部ではmuconodularな成分が優勢で，癌の深達度は固有筋層の表層に達し，ly₁，v₀，n₀であった．

　A 58-year-old man visited our hospital with a chief complaint of increased bowel movement. Laboratory studies showed normal except for positive immunochemical reaction of fecal occult blood. Barium enema x-ray and colonoscopic examinations revealed a flat elevated lesion in the transverse colon. This lesion was oval, irregular shaped, and slightly depressed in the center. Colonoscopic examination showed that the mucosa of flat elevated area looked normal.

　The operation was performed on November 21, 1990. The resected specimen disclosed the flat elevated lesion with shallow central depression was 16×12 mm in size. Histological examination showed well differentiated tubular adenocarcinoma with muconodular component which was predominant in the deep submucosal layer. Cancer cells invaded extensively into the superficial muscularis propria. No metastatic lesion was noted on the resected lymph nodes.

　This case is considered to be valuable to understand the natural course of a small flat elevated cancer which seemed to invade the muscularis propria.