大腸sm癌の診断と治療―内視鏡診断の立場から

The Diagnosis and Treatment of Colorectal sm Cancer

要旨　早期大腸癌430病変の中でsm癌は76病変（15.6％）を占めた．sm癌の内視鏡診断には，明らかな陥凹，内視鏡的硬さ，pit pattern V型などが有用である．平坦・陥凹型癌は小さくともsm浸潤癌が多い．表面型早期癌の初期sm浸潤様式は，①脈管周囲浸潤型，②粘膜筋板破壊型に分けられ，更にsm時期における浸潤形式は，①垂直進展型，②側方圧排型，③表層拡大型の3型に分類された．sm浸潤度分類はsm癌の治療法を選択するにあたり有用である．

　From April 1985, to February 1991, we found and treated 430 lesions of early colorectal cancer, 76（17.7%) of them were sm-cancer. Gross forms of sm-cancer were 39 lesions of protruded type（Ⅰp, Ⅰps, Ⅰs), 24 flat and elevated type（Ⅱa, Ⅱa＋Ⅱc), 11 flat and depressed type（Ⅱb, Ⅱc, Ⅱc＋Ⅱa), and 2 creeping tumor. Most of the flat and depressed lesions were small cancers under 10 mm in diameter. Concerning flat and depressed type lesions, the sm infiltration degree was 12.5% for lesions under 5 mm, and 31% for those under 10 mm in diameter. This suggests that some minute cancer lesions infiltrate deeply.

　It seems important in endoscopical diagnosis of flat and depressed cancer to notice if there is pale redness or fading of mucosal color, transformation according to the change of air quantity inside the colon, disappearance of innominate grooves, and disappearance of the pit structure.