除菌後発見胃癌の内視鏡診断—狭帯域光拡大観察の見地から：表面微細構造に焦点を当てて

Microsurface Structure of Early Gastric Cancers Detected after Helicobacter pylori Eradication Using Magnifying Endoscopy with Narrow Band Imaging

要旨●内視鏡治療前にNBI拡大観察を行ったH. pylori除菌後発見胃癌106例122病変に対して，範囲診断困難性を3段階で評価した．レベル1は80病変（66%）あり，病変辺縁部に不整微小血管像を認め，高確信度で境界の同定が可能であった．境界同定不可またはマーキングから1mm未満のレベル3は7病変（6%）あり未分化型が中心であった．境界の同定が低確信度またはマーキングから16mm以上のレベル2は35病変（29%）あった．レベル2の半数で乳頭・顆粒状の表面微細構造を認め，病理組織学的所見との対比によって，①非腫瘍性上皮の被覆・混在，②胃型分化型腺癌，③小腸型低異型度中分化型腺癌に対応するNBI拡大所見の特徴が認められ，グループに分けて評価することで，範囲診断能向上が期待できる．

　We evaluated the microvascular and microsurface pattern of 122 early gastric cancers detected in 106 patients who received successful Helicobacter pylori eradication therapy. The diagnostic difficulty of demarcation line using NBI-ME（magnifying endoscopy with narrow band imaging）for gastric cancers after eradication was ranked in three levels. High confidence（level 1, n＝80）was obtained in cancers with an irregular microvascular pattern. Low confidence（level 3, n＝7）was mainly observed in undifferentiated cancers. The papillary microstructure that resembled the adjacent noncancerous mucosa was observed in approximately 50% of the cancers with middle confidence（level 2, n＝35）. NBI-ME revealed the following pathological findings in cancers with papillary microstructures ; （1）non-neoplastic superficial epithelium and（2）surface differentiation of tubular adenocarcinoma with gastric or small intestinal mucin phenotypes.