Barrett食道腺癌の病理学的特徴—LSBEを中心に

Characteristics of Pathological Findings in Long-segment Barrett's Esophagus-Derived Esophageal Adenocarcinoma

要旨●Barrett食道腺癌のうち，LSBEに発生する腺癌（LSBE腺癌）の病理学的特徴をまとめた．Barrett食道腺癌は肉眼的に，0-I型や0-IIa型の隆起を示すことが多いが，LSBE腺癌では，0-IIb型あるいは主病変の周囲に0-IIb型成分を伴うことが多い．病理組織学的には高分化・中分化腺癌が多いが，浸潤とともに低分化腺癌成分が出現する傾向にある．0-IIb型成分は主に高分化腺癌成分から成るが，辺縁部では腺管密度が低く，細胞異型も軽度となる．LSBE腺癌の背景粘膜には腸上皮化生がみられることが多いが，噴門腺型粘膜としばしば混在する．LSBE腺癌には同時性・異時性多発が多く，背景粘膜には顕微鏡的微小病変も多く見い出される．多発微小病変の病理組織学的検出にp53免疫染色は有用である．

　This review demonstrates the pathological characteristics of adenocarcinoma in the long-segment Barrett's esophagus（LSBE adenocarcinoma）. Macroscopically, LSBE adenocarcinoma typically shows superficially elevated morphology, such as 0-I or 0-IIa lesions, which are occasionally accompanied by a 0-IIb component. Histologically, well-to-moderately-differentiated adenocarcinomas are commonly detected, but poorly differentiated components may be seen in deeper, more invasive regions. The 0-IIb component of LSBE adenocarcinoma comprises well-differentiated tubular adenocarcinoma with low glandular density and low-grade cellular atypia. Intestinal metaplasia is frequently observed in the background mucosa of LSBE adenocarcinoma. Multiple synchronous and metachronous lesions, including microscopic minute cancer foci, are common in LSBE adenocarcinoma. p53 immunohistochemistry is useful for the histological detection of such minute lesions.