Buried Barrett粘膜から発生したBarrett食道腺癌の1例

Barrett's Esophageal Adenocarcinoma Arising from Buried Barrett's Mucosa, Report of a Case

要旨●患者は60歳代，男性．逆流性食道炎でボノプラザンを長期内服しており，2年前の内視鏡検査でburied Barrett粘膜を伴うshort segmental Barrett's esophagusを認めた．今回同部位に上皮下腫瘍様隆起を認めた．内視鏡的に切除され，最終診断はBarrett食道腺癌〔Jz，11×8mm，pType 0-Is，pT1b-SM2，tub1-2>por，Ly（＋），V（＋），HM0，VM0〕であった．病理組織学的に分化型管状腺癌と低〜未分化な癌胞巣を認め，表層は扁平上皮で被覆されていた．CDX2は腫瘍全体で陽性，管状腺癌はp53陽性，MUC6陽性，低分化腺癌成分はp53陰性，MUC6陰性，MUC2陽性であった．不完全型腸上皮化生（p53陰性，MUC6陰性）も併存していたが，管状腺癌は噴門腺型上皮（MUC6陽性，p53とCDX2が部分的に陽性）と広く接しており，噴門腺型上皮からの発癌の可能性が示唆された．本症例はburied Barrett粘膜に発生した癌であり，極めてまれな症例と考えられた．

　A male patient in his 60s who had been taking long-term vonoprazan for reflux esophagitis underwent a follow-up EGD（esophagogastroduodenoscopy）, which revealed a subepithelial tumor-like elevated lesion. The EGD two years ago revealed a short segmental Barrett's esophagus with buried Barrett's mucosa at the same site. The lesion was endoscopically resected, and the conclusive diagnosis was Barrett's esophageal adenocarcinoma（Jz, 11×8mm, pType 0-Is, pT1b-SM2, tub1-2>por, Ly（＋）, V（＋）, HM0, VM0）. Histological examination revealed differentiated tubular adenocarcinoma and poorly differentiated to undifferentiated adenocarcinoma, and the squamous epithelium covered the superficial layer. The whole tumor was positive for CDX2, and the tubular adenocarcinoma component was positive for p53 and MUC6. Poorly differentiated to undifferentiated adenocarcinoma component was negative for p53 and MUC6 and positive for MUC2. The tumor was in wide contact with cardiac gland-type mucosa that was positive for MUC6 and partially positive for p53 and CDX2, indicating the possibility of carcinogenesis of differentiated adenocarcinoma from cardiac gland-type mucosa. This is the first report of Barrett's esophageal adenocarcinoma that originated from buried Barrett's mucosa.