形態変化を観察できた横行結腸のⅡc＋Ⅱa型早期大腸癌の1例

Type Ⅱc＋Ⅱa Early Colon Cancer in which Chronological Change could be Traced, Report of a Case

要旨　患者は81歳，男性．S状結腸癌切除後のサーベイランスで，横行結腸にⅡc＋Ⅱa型の表面型大腸腫瘍を指摘された．注腸X線検査で大きさ13×10mmの丈の低い周堤隆起を伴う陥凹性病変を描出し，拡大電子内視鏡，超音波内視鏡検査でⅡc＋Ⅱa型のsm癌と診断し，横行結腸部分切除が施行された．3年前の注腸X線フィルムをretrospectiveに検討すると，この病変は大きさ6mmのⅡa病変であり，この時点でm癌であった，横行結腸肝彎曲側の大きさ5mmのⅡa＋Ⅱc病変とほぼ同様の形態を呈していた．自験例はⅡa→Ⅱc＋Ⅱaの形態変化を示したが，発育速度は緩徐であった．表面型大腸癌の発育経過を考えるうえで，自験例は興味深い症例であると考えられた．

　A superficial lesion, type Ⅱc ＋ Ⅱa, was observed in the transverse colon of an 81-year-old man patient during colonoscopic surveillance after an operation for sigmoid colon cancer. Barium enema x-ray revealed a depressed lesion with marginal elevation, sized 13 × 10 mm in diameter. By magnifying observation and EUS, the diagnosis of Ⅱc ＋ Ⅱa type cancer with submucosal invasion was made and partial resection of the transverse colon was performed. By reviewing the barium enema x-ray taken three years before, the presence of a IIa type lesion sized 6 mm in diameter was confirmed at the same site. It was similar to another Ⅱa ＋ Ⅱc type mucosal cancer located more proximally at that time. In this case, transition from Ⅱa to Ⅱc ＋ Ⅱa was demonstrated, but its growth had been slow. This case was interesting for considering the natural course of superficial type cancer.