症例は67才男性.上部消化管内視鏡検査で胃前庭部前壁に0-I+IIc型隆起性病変を指摘され,生検結果は低分化型腺癌の診断であった.適応拡大病変と診断して内視鏡的胃粘膜下層剥離術(ESD)施行し適応拡大治癒切除であった.フォローの内視鏡で初回病変の近傍に0-I+IIc型の隆起を主体とした病変を認め,生検結果は印環細胞癌であり,再度ESDを施行した.初回病変のような,隆起を主体とした未分化型粘膜内癌の症例は稀である.二回目の病変の成因は,局所再発・腫瘍移植(implantation)・異時性癌のいずれか確定は困難であったが,貴重な症例と思われたので報告したA 67-year-old man was diagnosed with a small elevated undifferentiated gastric adenocarcinoma in situ and subsequently underwent endoscopic submucosal dissection (ESD). Curative resection was achieved. Fifteen months later, a new lesion was found near the ESD scar of the first lesion. This lesion was similarly elevated, and histopathological examination of the biopsy specimen revealed signet ring cell carcinoma. We performed ESD again for this lesion. Elevated early gastric cancer in which histological examination shows undifferentiated adenocarcinoma and depth M is very rare. We searched for elevated early undifferentiated gastric cancers in the PubMed and Ichushi databases and find only nine cases. The cause of the second lesion was suspected to be either local recurrence, or implantation or metachronous cancer, but it seemed to be very difficult to diagnose exactly. It should be careful observation, even if obtained curative resection of undifferentiated intramucosal gastric cancer by ESD
