食道胃接合部腺癌の範囲診断—特に扁平上皮下進展

Evaluation of Tumor Extent in Esophagogastric Junction Adenocarcinoma, Focusing on Sub-squamous Extension

要旨●SSBE由来のBACを含め，噴門部胃癌を除いた食道胃接合部腺癌に対する内視鏡診断，特に腫瘍露呈部と扁平上皮下進展の質的診断および範囲診断について検討した．32病変を対象としてJES-BE分類による腫瘍露呈部の診断精度は極めて良好であった．ただしMP（mucosal pattern）は視認できるが不整の判定に苦慮し，VPも判定が難しい場合は酢酸撒布により構造を明瞭化することが有用である．扁平上皮下進展は32病変中22病変（68.8%）に認め，進展距離中央値は4.5（0.5〜22）mmであった．その質的，範囲診断に対する各モダリティでの検討ではNBI併用拡大内視鏡が最も有用であり，brownishな色調変化，血管不整および開口所見が重要である．酢酸併用NBI観察による開口所見は視認性が向上し有用な所見であるが，その出現率は約70%であるため，進展範囲診断には各モダリティでの総合的な判断が必要である．

　We investigated the endoscopic diagnosis of esophagogastric junction adenocarcinoma（EGJAC）, excluding gastric cardia cancer, including Barrett's adenocarcinoma（BAC）arising from short-segment Barrett's esophagus（SSBE）, with a particular focus on qualitative and extent assessment of the exposed tumor component and sub-squamous extension.

　Thirty-two lesions were evaluated with excellent diagnostic accuracy of the exposed tumor component based on the JES-BE classification. However, although the mucosal pattern（MP）was often visible, it was sometimes difficult to assess irregularity and challenging to evaluate the vascular pattern（VP）. In such cases, acetic acid application was useful for enhancing mucosal structures and facilitating assessment.

　Sub-squamous extension was observed in 22 of 32 lesions（68.8%）, with a median extension length of 4.5mm（range, 0.5-22mm）. Narrow-band imaging（NBI）endoscopy was the most efficient of the various imaging modalities used for the evaluation of qualitative features and the extent of sub-squamous extension. Key findings included brownish discoloration, vascular irregularity, and the presence of an orifice sign.

　The orifice sign, observed with NBI endoscopy combined with acetic acid application, improved visibility and was a useful diagnostic finding ; however, because its detection rate was approximately 70%, comprehensive assessment using multiple imaging modalities is required for accurate delineation of the extent of sub-squamous extension.