大腸sm癌の診断―X線・内視鏡の立場から

Endoscopic and Radiological Diagnosis of Early Colorectal Cancer with Submucosal Invasion

要旨　早期大腸癌225病変（m癌：187病変，sm癌：38病変）を対象としsm癌の特徴について検討した．陥凹を有する表面型早期癌（Ⅱｃ，Ⅱc＋Ⅱa，Ⅱa＋Ⅱc）中のsm癌の頻度は陥凹を有さない表面型早期癌（Ⅱa），隆起型早期癌（Ⅰp，Ⅰsp，Ⅰs）のそれに比べ明らかに高く，sm₃11病変中9病変（81.8％）は陥凹を有する表面型であった．隆起部における表面凹凸不整の存在はsm癌診断の補助的役割を果たし，陥凹面における凹凸不整はsm massiveな癌診断の根拠になると思われた．X線的には，側面像における病変基部の変形所見はsm癌の診断に有用であった．また陥凹部の描出能は不良で，表面凹凸不整像（顆粒状あるいは結節状）の描出能は比較的良好であった．

　225 early colorectal cancers (m:187 lesions, sm:38) were studied for characteristics of submucosal invasion.

　Incidence of submucosal cancer was apparently higher in superficial early cancers with depression (Ⅱc, Ⅱc＋Ⅱa, Ⅱa＋Ⅱc) than that in those without depression or in those with elevated type (Ⅰp, Ⅰsp, Ⅰs). In addition, 9 (81.8%) out of 11 sm₃ lesions were of the depressed type of superficial colorectal cancer.

　Superficial granularity and nodularity on elevated lesions were of great help in diagnosing submucosal invasion of cancer. The same features on the depressed area of lesions also gave possible evidence of massive submucosal invasion of cancer.

　In the radiological study, profile configuration of the lesion base gave a good diagnostic indication of submucosal invasion of cancer.

　Depressed area of the lesion was poorly detected but irregularity (granularity and/or nodularity) was re-latively well demonstrated by x-ray examination.