有茎性ポリープから発育進展した大腸粘液癌の1例

Mucinous Carcinoma of the Rectosigmoid Colon, Transforming from a Pedunculated（Ip type）Polypoid Cancer in about One Year, Report of a Case

要旨　患者は40歳の男性で腹痛のため当院を受診した．注腸X線検査により直腸S状部に17mm大で，頭部にびらんを伴う有茎性ポリープ（Ip）を認めた．茎は緊満しSM癌と考えられた．その後来院しなかったが，約1年後下痢で入院した際に，注腸X線，大腸内視鏡検査を施行した．同病変は，頂部の陥凹内に隆起を伴う2型大腸癌に変化していた．切除標本の組織学的検索では，陥凹部の表層粘膜には主に印環細胞癌，粘膜下層以深では粘液癌の所見を認め，深達度SEの粘液癌と診断した．Ipの形態変化が追跡可能で最終診断が粘液癌であった報告はなく，大腸癌の発育進展を考えるうえで貴重な症例と思われた．

　A 40-year-old male was referred to our hospital because of abdominal pain. Barium enema revealed a pedunculated polypoid lesion with a shallow depressive area on the surface of the head and tensed thick stalk, approximately 17mm in size, in the rectosigmoid colon, which was presumed to be an early colonic cancer invading to the submucosal layer. However, the patient did not revisit for further treatment. About one year later, he was admitted due to watery diarrhea. At this time barium enema showed an elevated lesion like a submucosal tumor in the same area. The top of the lesion was depressed and the center was protruded. It looked like a pumpkin in appearance（2-type cancer）. The biopsied specimen revealed signet-ring cell carcinoma. High anterior resection was performed. The resected specimen revealed the signet-ring cell carcinoma with poorly differentiated adenocarcinoma mainly in the mucosal layer and mucinous carcinoma from the submucosal layer to the serosa. Finally we diagnosed mucinous carcinoma of the colon.

　Mucinous carcinoma, transforming from a pedunculated polyp, has never yet been reported.