早期胃癌と紛らわしい病変のX線，胃カメラ，生検による総合診断

On the Discrimination between Early Gastric Cancer and its Simulating Lesions by Means of X-ray, Gastrocamera and Biopsy

はじめに

　胃疾患の診断の進歩により，最近では微細病変がとらえられるようになった．筆者らの施設でも1cm以下のいわゆる微小胃癌が6例発見されているのは，X線および内視鏡検査の発達を如実に物語るものである．そして，発見された早期癌も従来の定型的なものは勿論だが，切除胃の肉眼所見をみても，これが癌かと一驚する症例も報告されるようになってきている．しかし一方では，術前早期胃癌を疑って手術を行ない良性病変であった例もしばしば報告されている．

　今回のテーマは早期胃癌と紛らわしい病変であるが，当院では，癌，もしくはその疑のあるものを優先して手術するわけで，特に胃生検を実施してからこの傾向はかなりつよく，非癌病変の手術例は少ない．

　今回は胃生検を実施できたこの5年間の手術例にしぼり，早期胃癌に紛らわしい病変を検討したい．

　Lesions closely resembling early gastric cancer have been discussed centering on surgically operated cases.

　Lesions simulating Ⅱa type Ⅰ early gastric cancer include adenomatous polyp and submucosal tumor. For their discrimination x-ray and endoscopy must be fully utilized. Of importance is to see whether there is a constriction on a tumor. If there is none, the tumor is assurely a submucosal one. If otherwise and pedunculated, the tumor must be strongly suspected as cancer, the more so when it is more than 2 cm in diameter. A sessile tumor, even less than 2cm in width, can be a malignant one.

　Lesions closely resembling type early cancer are submucosal tumor, atypical epithelium, erosive gastritis and so forth. Whether or not a tumor is of epithelial origin can best be assessed by the absence of constriction around it. Submucosal tumor can thus be ruled out. At a first glance, erosive gastritis may also present similar findings to those of Ⅱa or Ⅱa+Ⅱc, but it can be distinguished by the presence of allied lesions in its adjacent areas. Adenomatous polyp mimicking Ⅱa is mostly cancerous if it is more than 2cm in diameter; if less than 2cm in width, it usually is atypical epithelium.

　Lesions looking like Ⅱb type early cancr include atrophic and engorged flecks, and a fleck that is hardly distinduishable from normal mucosa in its color. A Ⅱb has been found from an engorged fleck, but caution is urged because there are noncancerous reddend flecks.

　For lesions resemblig Ⅱc or Ⅱc+Ⅲ type, RLH, malignant lymphoma and ulcer scar with its surrounding atrophy must be taken into account. They usually give themselves away by smooth mucosal tips and because these lesions cannot be traced in their whole circumference.

　Mention must also be made of acute ulcer and ulcer associated with gastritis as lesions closely resembling type and Ⅲ and Ⅲ+Ⅱc. Because they are otherwise hard to distinguish, biopsy is an indispensable procedure in their diagnosis.