内視鏡経過例における胃癌発育の遡及的検討―背景粘膜からみて

Retrospective Study of Early Gastric Cancer Followed by Endoscopic Examination in Relation to Mucosal Background

要旨　早期胃癌の内視鏡画像を遡及的に検討し，特に背景粘膜からみた早期胃癌の自然史について考察した．対象は41病変，平均観察期間は2.4年であった．最終病理診断で粘膜内癌の診断を得たものは34病変（82.9％）．粘膜内癌の間は発育速度が緩やかで，背景粘膜の違いによって明らかな差異は生じないものと考えられた．また，癌の初期像を検討したところ，背景粘膜が固有腺領域の外側（F，f領域の外側）では，隆起型の初期像は顆粒状の粘膜隆起を示し，陥凹型の初期像は発赤調の極めて浅い陥凹を呈した．これに対し固有腺領域（F，f領域内部）は，未分化型は3病変のみであり，遡及的な内視鏡像の検討でその初期像を同定することが困難であった．早期胃癌の自然史の全貌を解明するには，未分化型微小胃癌の診断方法を確立することが今後の課題であると考えられた．

　We performed a retrospective study of endoscopic images of early gastric cancer lesions to investigate the natural history of this disease in relation to mucosal background. Forty-one cases were observed for an average of 2.4 years. Thirty-four cases (82.9％) were histologically diagnosed as intramucosal carcinoma, which were slow growing and seemed to have no major variations related to their mucosal background. Moreover, the initial pictures of carcinoma were evaluated. In the lesions located outside the gastric glands (outside the Ff region), early-stage protrusion-type carcinoma showed granular mucosal protrusion, while early-stage depression-type carcinoma showed redness and very shallow depression. On the other hand, in the lesions within the gastric glands (within the Ff region), only 3 cases were of an undifferentiated type, which were difficult to identify from the initial endoscopic findings by retrospective study. To determine the whole natural history of early gastric cancer, it will be necessary to establish diagnostic methods for even small undifferentiated gastric carcinoma lesions.