三次元CTが診断に役立った大腸癌の1例

Colon Cancer Successfully Diagnosed by CT Colonography, Report of a Case

要旨　患者は73歳，男性．めまいを自覚し，近医で脾彎曲部に狭窄性大腸癌を指摘され，当科を受診した．大腸内視鏡検査では脾彎曲部の大腸癌による狭窄のため，口側は検査できなかった．注腸X線検査では脾彎曲部に強い狭窄を呈する病変が認められ，口側の横行結腸に病変は認められなかった．CTCによるvirtual endoscopyで，脾彎曲部の狭窄病変の他に横行結腸中央部の病変が新たにIIa＋IIc型の病変として描出された．術中内視鏡検査で，virtual endoscopyと近似した内視鏡像が得られ，SM癌が強く疑われたため，2つの病変をともに切除する形で結腸左半切除術を施行した．主病変は深達度pSSの進行癌であり，副病変は深達度pSMの早期癌であった．CTCは狭窄性大腸癌の口側の検索に有用である．

　A 73-year-old man visited our hospital because of an OCC（occlusive colon cancer）at the splenic flexure, diagnosed by a local doctor. Oral side of the OCC could not be examined by colonoscopy because a fiberscope could not pass through the stenosis. Gastrographin enema study showed the OCC but did not detect another lesion of the transverse colon. Virtual endoscopy by CT colonography showed both the OCC and a IIa＋IIc type lesion at the central portion of the transverse colon. Because intraoperative colonoscopy showed the same figure as virtual endoscopy, the IIa＋IIc type lesion was thought to be a cancer with submucosal invasion. Left hemicolectomy resecting both cancers was performed. The OCC was shown to be an advanced cancer with subserosal invasion, and the other lesion was an early cancer with submucosal invasion.

　CT colonography is useful for examination of the oral side of OCC.