A 型胃炎は稀な疾患で，悪性貧血や胃癌，胃NET の発生母地として知られている．抗胃壁細胞抗体陽性，高ガストリン血症，さらに胃体部を中心とした萎縮性胃炎が診断基準とされている．今回，過去１年に４例のA 型胃炎を診断した．全例で自覚症状は見られなかったが，内視鏡検査での逆萎縮所見からA 型胃炎を疑い，胃生検の病理所見と血液検査で確診した．A 型胃炎が他の自己免疫性疾患に合併することが多いとされているが，本症例にも高齢発症のBasedow 病が１例あり，A 型胃炎は日本でも決してまれな疾患ではないと考えられた．診断には内視鏡所見からA 型胃炎を疑うことが重要で，胃生検や血清ガストリンと抗胃壁細胞抗体の測定を行うことにより確診できる．Type A gastritis is a rare disease and is known as a cause of various conditions including pernicious anaemia, gastric cancer and gastric NETs (Neuroendocrine tumour). The diagnostic criteria of type A gastritis include positive parietal cell antibody, hypergastrinaemia and the presence of atrophic gastritis mainly corpus predominantly atrophic gastritis. We diagnosed four cases of type A gastritis in the past year in our hospital. Although they were all asymptomatic, type A gastritis was suspected by the endoscopic findings (the reverse atrophy) and all confirmed by pathological examination of biopsy specimens and blood test subsequently. It is well known that the patients with autoimmune disease are frequently associated with type A gastritis and there is a case of late onset of Basedow’s disease in our case report. Our study suggests that type A gastritis is not as rare as initially thought in Japan. In order to diagnose type A gastritis, it is important to have a high index of suspicion with endoscopic findings, and to confirm it with gastric biopsy, serum gastrin level and parietal cell antibody
