S状結腸銀還元性カルチノイドの1例

Argentaffin Carcinoid of the Sigmoid Colon, Report of a Case

要旨　患者は52歳男性，下腹部痛を主訴に受診，下部消化管内視鏡検査にて肛門縁より20cmのS状結腸に8mm大の隆起性病変を指摘され内視鏡的切除が施行された．組織学的には均一小型の上皮性細胞の索状～小腺管様増殖から成る腫瘍であり，組織化学的にほとんどすべての腫瘍細胞が細胞質内銀還元性顆粒を有することから銀還元性カルチノイドと診断された．本邦における大腸カルチノイドの大半は直腸に存在し結腸の報告は少ない．さらに従来胎生学的分類による後腸系カルチノイドは銀還元性を示すことは少ないとされる．本症例はS状結腸に発生し，かつ銀還元性カルチノイドであったので大変まれな症例と考え報告した．

　A 52-year-old man come to our hospital with the chief complaint of lower abdominal pain. Colonoscopic examination revealed a protruded tumor measuring about 8 mm in the sigmoid colon. Endoscopic resection was performed. Histologically, the tumor was composed of uniformly small epithelial cells arranged in tubular and trabecular fashion. Histochemically, almost all the tumor cells had intracytoplasmic argentaffin granules, so the lesion was diagnosed as an argentaffin carcinoid. In this country, large bowel carcinoid is mostly found in the rectum, and it usually shows no argentaffin. This case was an argentaffin carcinoid which occurred in the sigmoid, so we report it because we regarded it as a rare case.