Helicobacter pylori陰性未分化型超微小早期胃癌の1例

Helicobacter pylori-Negative Extremely Minute Early Gastric Cancer of Undifferentiated Type, Report of a Case

要旨　患者は60歳，男性．心窩部痛を主訴に当科を受診した．上部消化管内視鏡検査を施行したところ，胃体部から胃角部までRAC（regular arrangement collecting venules）像が観察され，Helicobacter pylori（H. pylori）感染のない背景粘膜と判定した．萎縮のない胃底腺領域内の胃角部大彎に長径2mmの孤立した褪色域を認め，生検の病理組織学的診断はGroup V，signet-ring cell carcinomaであった．生検痕を含めてESDにて病変を一括切除したが，ESD後切除標本内に病変は認めなかった．除菌歴の既往，H. pylori感染がなく，内視鏡的萎縮や組織学的胃炎を認めなかった．H. pylori陰性胃癌と診断した．内視鏡的に萎縮に乏しい胃底腺領域（特にM領域）の限局した褪色域が，H. pylori陰性の早期印環細胞癌の発見の重要な所見と考えられた．

　A 60-year-old man with epigastric pain was referred to the Department of Gastroenterology, Chikushi Hospital, Fukuoka University, Chikusino. A screening upper endoscopy revealed regular arrangement of collecting venules from the gastric body to the gastric angle ; this tissue was identified as background mucosa without Helicobacter pylori（H. pylori）infection. An isolated, discolored region 2mm in diameter was seen at the greater curvature of the gastric angle within the fundic gland region, which also did not show significant atrophy. The histopathological diagnosis based on the biopsy sample was group V, signet-ring cell carcinoma. ESD（endoscopic submucosal dissection）was performed to resect the lesion, including the biopsy scar, en bloc ; however, no lesions were observed in the resection sample following ESD, and the lesion had disappeared on biopsy. This patient had no history of H. pylori eradication and was negative for H. pylori infection ; in addition, he did not have endoscopic atrophy and histological gastritis. He was thus diagnosed with H. pylori-negative gastric cancer. In the initial routine inspection, a discolored region of the localized（M area in particular）fundic gland region showing little atrophy was a key finding for the early detection of H. pylori-negative signet-ring cell carcinoma.