Ⅱc＋Ⅰs型を示した早期大腸癌の1例

Ⅱc (depressed) +Ⅰs (sessile) Type Early Carcinoma of the Rectum, Report of a Case

要旨　患者は68歳，男性．3年半前に横行結腸癌にて右半結腸切除術を受けており，follow-upの大腸内視鏡にて直腸Rsに無茎性の隆起性病変と，それに連続して強い赤色調の平坦やや陥凹した病変の拡がりを認め，生検にて癌と診断，低位前方切除術を施行した．病変は10×8mmのⅠs型早期癌と7×4mmのⅡc型早期癌が連続しており，粘膜内に限局する深達度mの早期癌であった．Ⅰs型病変は一部腺腫成分が認められた．Ⅱc型と，Ⅱa以外の他の形態との連続病変の報告は少なく，今後このような発育形態を呈する症例の蓄積が望まれる．Ⅱc部分の内視鏡像の所見は純粋の大腸Ⅱc病変の所見と酷似していた．

　A right hemicolectomy was performed on a 64-year-old man who had transverse colon cancer. Three years after the operation, a follow-up colonofiberscopic examination revealed a 15×10 mm lesion in the upper rectum (Rs). It was described colonofiberscopically as a slightly depressed lesion with redness (Ⅱc) contiguous to a protruded lesion (Ⅰs). The depressed lesion was more clearly shown by increasing the amount of air in the rectum. The surrounding protruding element, on the other hand, emerged when the amount of air was decreased. Thus, he was diagnosed as having Ⅱc＋Ⅰs type early cancer.

　Histologically, the lesion proved to be well-differentiated adenocarcinoma confined to the mucosa. Histological contiguity to Ⅱc and Ⅰs lesions was demonstrated by examining the serial sections. The Is lesion contained an adenomatous element.

　Only a few reports, if any, on this kind of Ⅱc mixed type have been made so far in the literature.