PPI長期内服中に癌化した胃底腺ポリープの1例

Fundic Gland Polyp with High-grade Dysplasia Secondary to Proton Pump Inhibitor Therapy ongoing for 15 Years, Report of a Case

要旨●患者は50歳代，女性．逆流性食道炎に対する治療のためプロトンポンプ阻害薬（PPI）を内服中であった．内服開始1年後に胃ポリープが発生し，次第に増加，増大していった．ポリープ発生から15年後に最大のポリープは10mmを超え，同病変はNBI併用拡大内視鏡観察で腺癌が疑われる所見であったため，内視鏡的粘膜切除術（EMR）を施行した．病理組織学的には，low-grade dysplasiaとhigh-grade dysplasiaが併存したPPI関連胃底腺ポリープと診断した．dysplasiaが発生してから14年間の経過で浸潤癌にはならなかった．

　A fundic gland polyp is a common and benign gastric polyp. Dysplasia with fundic gland polyps is common in patients with hereditary gastrointestinal polyposis syndromes. However, high-grade dysplasia or carcinoma arising from sporadic fundic gland polyp is extremely rare. We present a case of fundic gland polyp with high-grade dysplasia secondary to PPI（proton pump inhibitor）therapy for 15 years. A woman in her 50s was admitted to our hospital due to irregular microvascular findings in endoscopic mucosal resection. Magnifying endoscopy with narrow band imaging revealed an irregular granular microsurface structure with irregular microvessels. Moreover, histological examination revealed high-grade and low-grade dysplasia in the epithelium of the fundic gland with large cystic dilations, and parietal cell protrusion and foveolar hyperplasia or hypermaturation were observed in the polyp. The MUC5AC and MUC6 were co-expressed in high-grade dysplasia in immunostaining. Therefore, the lesion was diagnosed as high-grade and low-grade dysplasia with fundic gland polyp secondary to PPI therapy.