直径7mmの微小結腸内分泌細胞癌の1例

A Minute Endocrine Cell Carcinoma of the Sigmoid Colon, Report of a Case

要旨　患者は72歳，男性．特に症状なく，便潜血検査陽性のため施行した大腸内視鏡検査でS状結腸に陥凹性病変が指摘され当院へ紹介された．形態は陥凹部の周囲がなだらかに隆起したIIa＋IIc型であり，拡大内視鏡観察では陥凹部は無構造で周囲に腫瘍性pitを伴っていた．超音波内視鏡での深達度診断はsm深部浸潤と推定した．S状結腸切除術が施行され，病理組織学的には粘膜に腺癌を伴い，粘膜下層から固有筋層まで浸潤する内分泌細胞癌で，腫瘍径は7mmで本邦報告中最小のものであった．当疾患に対し拡大内視鏡観察が行われた報告はなく，また，微小な病変であることより発生学的にも興味ある症例であった．

　A case of a minute endocrine cell carcinoma of the Sigmoid colon is reported. A depressive lesion was detected by colonoscopic examination in the Sigmoid colon of a 72-year-old asymptomatic man, following a positive fecal occult blood test, who was referred to our hospital for further evaluation of the colon. Colonoscopy revealed a IIa＋IIc type lesion, the depressive area of which was surrounded by smooth elevated mucosal findings with redness. In magnifying endoscopic appearance, the pit pattern of the depressive area was amorphous and was almost surrounded by neoplastic pits. Sigmoidectomy was performed. Pathologically, the tumor was an endocrine cell carcinoma with a well differentiated adenocarcinoma component which had expanded in the submucosa in a mass invading to the depth of the muscularis propriae (mp). The tumor was 7×7 mmin diameter, which is the most minute size recorded in the literature in Japan. We have never encountered a magnifying endoscopic study of endocrine cell carcinoma, and the minute size of the one reported here is extremely interesting from the viewpoint of embryology.

　1) Department of Internal Medicine, Amakusa Medical Center, Hondo, Japan

　2) Department of Gastroenterology, Kumamoto Red Cross Hospital, Kumamoto, Japan

　3) Department of Pathology, Kumamoto Red Cross Hospital, Kumamoto, Japan

　4) Department of Surgery, Kumamoto Red Cross Hospital, Kumamoto, Japan