内視鏡経過例における早期胃癌発育の遡及的検討―粘液形質からみて

Retrospective Study of Endoscopic Findings during Development of Early Gastric Cancer─Glandular Type

要旨　過去の内視鏡像の見直し診断で異常を指摘できた経過例121例を対象として，早期胃癌の発育進展を粘液形質の相違から解析した．粘液形質は，胃型46例，混合型32例，腸型42例，無形質型1例であった．症例の肉眼型は，表面型が117例とほとんどを占めていた．隆起型4例および表面隆起型33例の発育速度を腫瘍径で比較すると，混合型と胃型が腸型に比べて速く，その中で最も速かった症例は，約5年の経過で腫瘍径が約3倍となり，胃体部では経過中にSM浸潤を認めた症例もあった．表面陥凹型84例では，発育速度を深達度で比較すると，胃型と混合型は，組織型にかかわらず，2～4年の経過でSM浸潤癌となった症例が多かった．一方，腸型は，長期にわたって粘膜内癌のまま推移した症例が多かった．以上から，早期胃癌の発育速度を粘液形質から解析した結果，胃型と混合型の発育速度は類似しており，腸型に比較して速かった．

　Glandular type in the development of early gastric cancer was studied in 279 cases followed up by endoscopic examinations over a period of ten years. With regard to time course and diameter development, among 33 cases with surface protruded type, gastric gland type and mixed type showed faster growth than intestinal gland type. In addition, especially with regard to UM area, lesions with normal mucosal color and indistinct borders initially developed laterally and began to invade into the submucosal（sm）layer when more than 2 cm in diameter. Among the surface depressed type with well-differentiated carcinoma of gastric gland type and mixed type, irregular vessel dilatation becomes a depression with normal mucosa or reddened color and was observed as sm invasion with erosion. The gastric glands exist mostly on the greater curvature of the UM area in the stomach, and lesions that were originally signet ring cell carcinoma and signet ring cell carcinoma that had developed from gastric adenocarcinoma, normal to reddened in color with a slight granular surface, were found in the ductal area inside the concavity. Both gastric type and mixed type carcinoma included cases of well-differentiated adenocarcinoma with slight atypical cells and cases with well-differentiated lesions changed to undifferentiated adenocarcinoma invading deeper than the sm layer as well as metastasis into the vascular system. Therefore, diagnosis considering morphology and histopathological features along with the time course of progressing carcinoma is essential for detection of the lesions and choice of treatment, especially in gastric type and mixed type carcinoma.