プロトンポンプ阻害薬長期服用中に発生した胃底腺ポリープ内にdysplasiaを認めた1例

Fundic Gland Polyp with Dysplasia Developed during Long-term Proton Pump Inhibitor Therapy, Report of a Case

要旨　45歳，男性．非びらん性胃食道逆流症に対しランソプラゾール30mg内服15か月後，5mmの胃底腺ポリープ（FGP）を認め，さらに2年後10mmと増大，生検で表層にdysplasiaを認め，内視鏡的粘膜切除術を施行した．病理検査でdysplasia部はKi-67（＋）細胞が増加，p53（＋）細胞が散見，β-cateninは細胞膜のみ染色され，MUC5AC（＋）細胞が主となりMUC6（＋），MUC2（－），CD10（－）で胃腺窩上皮型の形質を示した．大腸ポリープを認めず，家族歴もないため，家族性大腸腺腫症は否定的であった．プロトンポンプ阻害薬関連FGP内にdysplasiaを認める症例が存在することを示した．

　A 45-year-old man developed a FGP（fundic gland polyp）of 5mm in diameter 15months after long-term treatment with lansoprazole 30mg once a day for non-erosive gastro-esophageal reflux disease. After 2 more years, the FGP increased to 10mm in size, and was revealed by biopsy to include dysplasia in the surface. Endoscopic mucosal resection was performed for the FGP with dysplasia. Histopathological examination showed increased Ki-67-positive epithelial cells and scattering of p53-positive cells in the dysplastic area as compared with the non-dysplastic area of the FGP. Beta-catenin was positive only on the cell membrane in both areas. The dysplastic area was composed mainly of superficial MUC5AC-positive cells and partly of subjacent MUC6-positive cells without MUC2- or CD10-positive cells. Familial adenomatous polyposis was denied because of the absence of colon polyps and there being no familial medical history. It was shown that it was a case of PPI（proton pump inhibitor）induced FGP with dysplasia.