表在型Barrett食道癌の病理学的特徴

Histopathologic Characteristics of Superficial Adenocarcinoma in Barrett's Esophagus in Japan

要旨●Barrett食道癌と診断された36例の病理学的特徴を検討した．肉眼型では隆起型がやや多く，粘膜下層浸潤部浸潤癌で隆起型の頻度はより高くなった．壁深達度診断においては，粘膜筋板二重化の認識が重要だが，判断に迷う場合もあり留意すべきと考えられた．組織分化度については，粘膜内で高分化〜中分化主体だが浸潤とともに低分化となる例が多かった．口側における扁平上皮下進展所見は高頻度に認められた．背景のBarrett粘膜は，SSBE（short segment Barrett's esophagus）が9割超を占め，LSBE（long segment Barrett's esophagus）は少なかった．リンパ節転移は1例のみに認めた．これら特徴を欧米と比較する際には病理診断基準の違いを理解するだけでなく，SSBEとLSBEの有病率の差やサーベイランス方法などの違いも含めて総合的に考える必要がある．

　The pathologic characteristics of superficial adenocarcinoma in Barrett's esophagus were analyzed in 36 consecutive cases from The Cancer Institute Hospital of the Japanese Foundation for Cancer Research. The protruding or slightly elevated type was more frequent than the flat or slightly depressed type. For the evaluation of the extent of invasion, identification of a double muscularis mucosa was important, although it was occasionally difficult. Regarding tumor differentiation, a majority of cases contained well-to-moderately differentiated components in the mucosa and poorly differentiated components in the submucosa.“Barrett's cancer under the squamous epithelium”was frequently observed. In this study, more than 90% of the cases had SSBE（short segment Barrett's esophagus）in the background mucosa, and LSBE（long segment Barrett's esophagus）was infrequent. Lymph node metastasis was found only in one case. When comparing these findings with those from Western countries, the differences in the histopathologic diagnostic criteria, the prevalence of SSBE/LSBE, and the surveillance methods need to be considered.