早期大腸癌の深達度診断―X線診断の立場からみたm，sm1とsm2,3の鑑別

Diagnosis of the Depth of Invasion in Early Colorectal Cancer: Differential Diagnosis between m, sm1and sm2,3 from the Roentgenographic Point of View

要旨　早期大腸癌254病変および陥凹型腺腫20病変を対象に肉眼形態別にX線によるm，sm₁とsm_2,3の鑑別について検討した．無茎性隆起型癌においては大きさに加え，表面構造から腺腫成分の有無を鑑別する必要がある．表面構造が平滑および結節状均一では腺腫成分の有無の判定は困難であったが，結節状粗大はほとんどが腺腫成分を伴わない単一癌であり，この所見は鑑別点になると思われた．腺腫成分を伴わない単一癌の表面構造による深達度診断を試みたが，表面平滑なものはすべてmであり，結節状粗大は80％がsm_2.3であった．陥凹性病変ではm，sm₁は陥凹部のバリウム斑が平坦均一で周辺隆起は表面平滑ないし結節状均一なものが多かった．一方，sm_2,3では陥凹部のバリウム斑が不均一で周辺隆起は表面に大小不同を伴う不均一な結節状を呈するものが有意に多かった．

　We studied differential diagnosis between m, sm₁and sm_2,3in 254 cases of early colorectal cancer and 20 cases of depressed adenoma, deviding them into several groups by macroscopic appearance, from the roentgenographic point of view. In sessile polypoid cancer, it is necessary to decide the existence of adenomatous components from the surface structure as well as from size. It was impossible to diagnose the existence of adenomatous components in the lesions of a flat or uniform nodular surface structure. However, most of the lesions of an irregularly gross nodular surface structure were cancers without adenomatous components, and this finding was suggested to be a key point for deciding the existence of adenomatous components. We tried to evaluate, from the surface structure, the depth of invasion in sessile polypoid cancers without adenomatous components. All lesions which had a flat surface structure were mucosal cancers and 80% of the lesions with irregularly gross nodules were sm_2,3. In depressed lesions, mucosal and sm₁ cancer had a flat and homogenous barium fleck in the depressed area and most of these had a flat or uniform nodular marginal elevation. However, the number of lesions with anhomogenous barium fleck or irregular nodular marginal elevation were more frequently found to be sm_2,3than m, sm₁.