早期胃癌診断の基本―Ⅱc型早期胃癌の内視鏡像

Endoscopic Diagnosis of Early Gastric Cancer: Diagnosis of Ⅱc Type Early Gastric Cancer by Conventional and Dye Endoscopy

要旨　Ⅱc型を中心とする陥凹性早期胃癌424病変を対象に，内視鏡的所見を通常内視鏡と色素内視鏡に分け検討した．陥凹面の性状は不整凹凸と無構造に大別されたが，分化型では不整凹凸，未分化型では無構造が有意で，胃小区模様の消失は深達度とも関連した．色調の変化も重要な所見で，分化型では発赤，未分化型では褪色が基本色調であるが，未分化型ではより多彩であった．陥凹面の所見では白苔，出血，陥凹内隆起，硬化像，辺縁の所見では病変範囲，蚕食像，ひだの変化などについて検討したが，Ⅱcに最も普遍的な所見は蚕食像で，殊に色素法で高率に認められ，ひだの変化は深達度と関連した．

　Endoscopic findings of Ⅱc type early gastric cancer were studied retrospectively. Four hundred twenty four lesions of type Ⅱc and type Ⅱc+Ⅲ, 190 lesions with well differentiated type and 234 lesions with undifferentiated type were selected randomly.

　Selected items were surface structure of Ⅱc, change of color, white coat, bleeding, protrusion in depressed area, rigidity, margin of lesion, encroachment, surrounding elevation, changes of converging folds. Disappearance of gastric area was the major sign of undifferentiated carcinoma, and uneven mucosa was the characteristic endoscopic finding of differentiated adenocarcinoma.

　Change of color was another important finding of the Ⅱc area.

　In differentiated carcinoma, mucosal reddening was seen in more than 70% of the cases. In undifferentiated type, discoloration and scattered reddening was a characteristic finding of the Ⅱc area. Protrusion within the depressed area was more frequently seen in undifferentiated carcinoma. Encroachment was another characteristic endoscopic finding of Ⅱc, and these findings were seen markedly in dye endoscopy. Changes of converging mucosal folds were seen in almost all cases. Abrupt stopping and tapering of folds was seen in more than 60% of cases of Ⅱc type with converging folds.