陥凹性早期胃癌診断困難例の克服―内視鏡診断を中心に

Overcoming of Diagnostic Difficulties in Depressed Types of Early Gastric Carcinoma

　早期胃癌陥凹型といえば，つまりⅡcおよびⅢ型，それに両者のcombinationであるⅡc＋Ⅲ，またはⅢ＋Ⅱc型をさす．その他亜型として，ⅡcとⅡaの併存する病変も比較的よく見るものである．内視鏡的には，Ⅱcは良性潰瘍瘢痕と，Ⅱc＋Ⅲ，Ⅲ＋Ⅱcは治癒性良性潰瘍との鑑別困難例にしばしば遭遇する¹⁾²⁾．今ここで一つの陥凹型早期胃癌らしい病巣を発見した場合，癌細胞が粘膜下層（早期癌）までにとどまるか，固有筋層（進行癌）に浸潤しているかを推察することより，良性疾患との鑑別の方が臨床的に，つまり患者に対する治療面において遙かに重要なことである．筆者らは良性，悪性の鑑別が難しかった陥凹型早期胃癌例における反省から，表在性胃癌の特徴的所見であるⅡcにつき考察を深めるため，retrospectiveに症例検討を試みた．

　To overcome diagnostic difliculties in depressed types of early gastric carcinoma in which carcinomatous invasion is limited to the mucosa or/and submucosa, a review study of the cases misinterpreted as benign gastric ulcer was presented for a discussion on differentiation between Ⅱc (slightly depressed type of early gastric carcinoma) and Ⅱc like benign depression.

　The fact was emphasized that a stair-like depression with a sudden disruption of converging folds at the margins was observed not only in a malignant lesion, but also in a healing benignancy.

　Finally, the following was discussed as a summary. First of all, more detailed discussion on the features of Ⅱc appearing area of a lesion by more than a couple of encloscopists will be needed on the basis of photographs, and characteristic findings of Ⅱc such as thinning or clubbing of folds at or in the vicinity of the lesion should be properly interpreted.

　Secondly, a close follow-up of the lesion should be performed to follow endoscopic changes in Ⅱc appearing area and its adjacent mucosae, since an early malignancy discloses characteristic features of Ⅱc, particularily in the healing process.

　Thirdly, one must be aware of the limitations in endoscopical diagnosis and should, sooner or later, apply cytology and biopsy techniques under direct vision to even a benign appearing ulcer.