10mm台の進行大腸癌のX線・内視鏡的特徴

Radiographic and Endoscopic Characteristics of Advanced Colorectal Carcinoma Smaller than 2 cm in Diameter

要旨　国立がんセンターにて1962年から1985年までに切除され，大きさが10～19mmの進行大腸癌は14例であった．X線，内視鏡，切除標本でその特徴像を検討した．その結果，腫瘍の起始部は山田のⅡ～Ⅲ型隆起を示し，また表面は分葉状ではなく結節状を呈し，12例(85.7％)は中心陥凹を伴っていた．一方，周囲粘膜と腫瘍との境界部では，健常粘膜が腫瘍の辺縁部に覆いかぶさるような形態を示す傾向がみられた．特にX線所見についてみれば，病変の側面像が得られた10例中全例に，腸管に弧状変形か台形状変形がみられた．弧状変形を示す例では，癌組織は固有筋層にわずか浸潤していた．しかし，台形状変形を示した例では，癌組織は固有筋層やそれ以下の層に中程度量以上浸潤していた．小さな進行癌の診断には，結節状で中心陥凹がみられる無茎性病変を発見し，特にX線学的には，病変の側面像における腸管の変形の分析を行うことが重要である．

　Fourteen advanced colonic cancers, 10-19 mm in size, experienced at National Cancer Center Hospital in 1962 through 1986 were studied with respect to their radiological, endoscopic, and pathological features. Tumors were elevated at the original sites and classified into either Yamada's type Ⅱ or Ⅲ. The surfaces were nodular and not lobular. Central depression was noted in 12 cases (85.7％).

　Normal mucosa surrounding the tumor tended to overlie the peripheral borderline area of the tumor.

　Radiologically, deformed colon in either arch or trapezoid shape was noted in all 10 cases in which profile views were obtained. Those cases with arch shape deformity proved to have massive cancer invasion into the submucosal tissue layer or minute invasion to the propria muscle layer. Those with trapezoid deformity, on the other hand, had more severe cancer invasion into the propria muscle or deeper layer.

　Thus, it is required in order to correctly diagnose small advanced cancer that nodular sessile lesion with central depression be recognized and that the deformity of the colon be analysed radiologically in the profile view.