病変の拡がりの診断に苦慮した早期胃癌の1例

Depressed Type Early Gastric Carcinoma Presenting with a Poorly Defined border, Report of a Case

要旨　患者は60歳，女性．上部消化管検診(直接X線検査)で異常を指摘され，内視鏡検査で早期胃癌の診断がなされた．癌の組織型は印環細胞癌であった．手術目的で当院外科に入院した．入院後の精密X線検査で，病変は胃体下部後壁に存在する粘膜異常(粗大顆粒状粘膜と不整な陰影斑)として，内視鏡所見では，褪色域中の発赤粘膜や散在する淡い白苔として認められた．色素撒布(インジゴカルミン)で褪色域の境界は血管透見像の消失として認められたがその境界は不明瞭であった．Ⅱc病変の周囲にⅡb様病変の存在することを考慮して口側と肛門側に点墨生検を行い癌陰性の粘膜を確認の後に胃切除術(幽門輪温存)が行われた．切除胃標本上，病変は粗大顆粒状粘膜と，その周囲の褪色域として認められたが病変境界は不明瞭であった．病理組織診断では低分化型腺癌(por2)，Ⅱc(Ul-Ⅱ)，m，大きさが30×25mmであった．

　A 60-year-old female was admitted to the Dept. of Surgery, Cancer Institute Hospital for the treatment of IIc type early gastric cancer which was first detected during a screening examination by direct radiography. Endoscopic examination with biopsy disclosed signet ring cell carcinoma. Detailed radiographic examination which was carried out after admission delineated a localized mucosal abnormality which consisted of an irregular depression with rough granularity in the posterior wall of the gastric body. Endoscopic examination revealed an area of discoloration in which redness and faintly whitish mucus were scattered. No capillary pattern was observed in the discolored area. However, even chromoendoscopy with indigocarmine could not delineate the whole lesion clearly. Pylorus preserving surgery was performed after the cancer-negative mucosa proximal to the lesion was confirmed by the India ink injection method. On the resected specimen, the lesion was seen as a mucosal depression consisting of nodular granularity and surrounding discoloration. Its border was poorly defined, and could not even be recognized macroscopically. Histologically, the lesion was diagnosed as type IIc simulating type IIb (Ul-II grade of ulceration), poorly differentiated adenocarcinoma (por2) limited to the mucosal membrane, measuring 30×25 mm.