胃異所性膵の膵管開口部に発生した早期胃癌に対しNEWSを施行した1例

Local gastric resection by non-exposed endoscopic wall-inversion surgery（NEWS）for early gastric cancer occurring in the ectopic pancreatic duct opening of the stomach

◆要旨：症例は76歳，女性．膵intraductal papillary mucinous neoplasms（IPMN）の精査中，上部消化管内視鏡検査にて胃体下部後壁小彎側に胃submucosal tumor（SMT）とその直上粘膜に0-Ⅱa病変を認め，生検にて胃癌と診断された．内視鏡診断上は粘膜内癌と考えられたが，SMT直上の早期胃癌にてendoscopic submucosal dissection（ESD）は困難と判断された．SMTはendoscopic ultrasound（EUS）にて分葉状構造を有する低エコー腫瘤で，内部にはduct-like structureを認め異所性膵が疑われた．胃SMTおよび早期胃癌に対し，non-exposed endoscopic wall-inversion surgery（NEWS）にて胃局所切除術を施行した．病理組織学的には異所性膵および早期胃癌の診断であり，早期胃癌は異所性膵の膵管開口部から広がっていた．異所性膵の膵管開口部に胃癌が発生した症例は非常に稀であり，さらに同症例に対しNEWSで切除した報告はなく，若干の文献的考察を加えて報告する．

　The patient was a 76-year-old woman who was diagnosed as having a gastric submucosal tumor（SMT）on the lesser-posterior wall of the lower body and a 0-IIa lesion immediately above it by upper gastrointestinal endoscopy while examining for pancreatic intraductal papillary mucinous neoplasms（IPMN）. When viewed on the endoscopic ultrasound, the SMT was a lobulated, hypoechoic mass containing a duct-like structure, suggesting ectopic pancreas. Although the 0-IIa lesion was presumed to be mucosal cancer based on the endoscopic diagnosis, endoscopic submucosal dissection was deemed difficult as it was directly above the SMT. Hence, local gastric resection was performed by non-exposed endoscopic wall-inversion surgery（NEWS）for the treatment of gastric SMT and early gastric cancer. The pathological diagnosis was ectopic pancreas and early gastric cancer, which had spread from the opening of the ectopic pancreatic duct. Gastric cancer in the ectopic pancreatic duct opening is extremely rare, and there is no report of similar cases treated by NEWS. Herein, we report the case with literature review.