表層拡大型早期胃癌の臨床診断―隆起型の境界診断の問題点

Diagnostic Study of Elevated Type of Superficial Spreading Type of Early Carcinoma of the Stomach

要旨　隆起型を示す表層拡大型早期癌の診断上の問題点について検討した．対象は1970年1月から1995年12月までに外科的切除された5cm×5cm以上の拡がりを持つ表層拡大型早期癌78例78病変である．同期間の早期胃癌切除例1,032例中の7.6％であったが，近年では5％以下に低下していた．組織型は分化型42例，未分化型36例，肉眼型は陥凹型56例，隆起型22例であった．隆起型の肉眼型をⅡa＋Ⅱc型8例，隆起型4例，隆起陥凹混在型8例の3群に分けて検討した．深達度診断については，sm率がⅡa＋Ⅱc型では100％，隆起陥凹混在型では50％と高いにもかかわらず，sm浸潤部を指摘することはX線上でも切除標本上でもできず，これらの病変では必ずsm癌と診断する必要があった．境界診断については，隆起陥凹混在型における口側境界の診断が不良で，この形態的特徴として8例中7例では隆起部分の口側に随伴Ⅱb様の平坦部分がみられ，しかも隆起部分よりも広い範囲に浸潤がみられた．

　Seventy eight cases of invading superficial spreading type of early gastric carcinoma (SSC), more than 5×5 cm² in size were investigated. Incidence of SSC was 7.6% of 1,032 cases of early gastric cancer between 1970 to 1995, but in the last 10 years it has decreased to less than 5% of the total. Histologically there were 42 cases of differentiated type and 36 cases of undifferentiated type, and the macroscopical finding was 56 cases of depressed type and 22 cases of elevated type.

　In this paper, the accuracy of diagnosis of elevated type of SSC, divided into three groups viz. Ⅱa+Ⅱc type, polypoid type and mixed type, was studied radiologically and macroscopically. The rate of cancer invading to the submucosa was 100% of Ⅱa+Ⅱc type and 50% of mixed type but it's impossible to point out the places of submucosal cancerous invasion. Hence, it is neseesary to diagnose submucosal involvements in such groups. It was hardly possible to diagnose how widely the mixed-type carcinomas had spread superficially because most of them had Ⅱb-like invasion at the oral side. When we encouter an elevated type of carcinoma, it is necessary to observe whether there is superficial invasion on the oral side of the cancer or not.