粘膜下腫瘍様の形態を呈した大きさ10mmのS状結腸ss癌の1例

Sigmoid Colon Cancer Mimicking Submucosal Tumor, Report of a Case

要旨　患者は52歳，男性．スクリーニング目的に施行した大腸内視鏡検査でS状結腸に病変を認め入院した．注腸X線検査ではS状結腸に大きさ10mm大で類円形を呈する隆起性病変を認めた．病変中央部には星芒状の陥凹を有し，側面像において孤状変形から台形状変形を呈していた．大腸内視鏡検査ではS状結腸に，大部分が正常粘膜に覆われた粘膜下腫瘍様の隆起性病変を認めた．隆起の頂部には星芒状の陥凹を有し，その周辺にも散在性に小陥凹がみられた．拡大観察を施行したところ，病変頂部の陥凹部はpitが消失していた．同部からの生検で中分化腺癌の診断が得られたため，粘膜下層以深に深部浸潤した大腸癌と診断し手術を施行した．病理組織学的には粘膜下層を主座とし漿膜下層まで浸潤した中分化腺癌であった．病変の形態および発育進展を考えるうえで興味ある症例と考え報告した．

　A 52-year-old man was admitted to our hospital for control of diabetes. Colonoscopic examination for health screening showed a submucosal tumor-like protruded lesion mostly covered with normal mucosa in the sigmoid colon. The lesion was accompanied by a central depression at the top and scattered small depressions in the marginal region. Barium enema radiograph with en face view revealed a round radiolucent area of 10 mm in size with a thick, irregular barium collection in the sigmoid colon. Barium enema radiograph with profile view demonstrated a semilunar deformity. Magnifying colonoscopic examination showed the absence of pits in the depressed portion and biopsy from the lesion revealed the presence of moderately differentiated adenocarcinoma. With a diagnosis of sigmoid colon cancer massively extending to the submucosal layer or more, sigmoidectomy was performed. Histopathologically the lesion was diagnosed as moderately differentiated adenocarcinoma, massively invading the submucosal layer and vertically extending to the subserosal layer. This case was thought noteworthy for the morphological properties of the tumor.