胃癌診断体系以外の有用な所見—vessels within epithelial circle（VEC）pattern：円形上皮内血管パターン

Vessels within Epithelial Circle Pattern

要旨●乳頭腺癌は管状腺癌と比べ，病理学的に生物学的悪性度が高いと報告されている．しかし，従来の通常内視鏡観察では乳頭腺癌を診断することは不可能であった．筆者らは，拡大内視鏡観察において円形の腺窩辺縁上皮で囲まれた円形の窩間部上皮下の間質に血管が存在する特徴的な所見を“vessels within epithelial circle（VEC）pattern”と呼称し，乳頭状の分化腺癌に特徴的な所見であると報告した．以前筆者らの報告した症例対照研究より，術前に分化型癌と診断された早期癌において，NBI併用拡大内視鏡により視覚化されるVEC patternが組織学的乳頭状構造を診断するうえで有用であったと報告した．さらに，VEC pattern陽性の早期胃癌の約1/4の病変に未分化型癌の混在や粘膜下層浸潤を認め，VEC patternが術前に癌の高い悪性度を予測するうえで有用なマーカーとなる可能性が考えられた．

　Conventional endoscopy is not useful for the diagnosis of papillary adenocarcinoma, which is pathologically more malignant than tubular adenocarcinoma. We report a novel characteristic pattern of differentiated papillary adenocarcinoma observed through high-magnification endoscopy, wherein vessels in the subepithelial intercrypt stroma were surrounded by circular marginal crypt epithelium. Furthermore, in a case-control study, we previously reported that this VEC（vessels within epithelial circle）pattern was useful for preoperative histological diagnosis of papillary structures in early differentiated gastric cancer using narrow-band imaging with high-magnification endoscopy to visualize the VEC pattern. In addition, concomitant undifferentiated carcinoma and submucosal invasion were observed in approximately 25% of the VEC pattern-positive early gastric cancer lesions, which suggested that the VEC pattern is a useful preoperative predictive marker for high malignancy potential of gastric cancer.