外傷性膵損傷術後に発生した仮性嚢胞に対して内視鏡的に十二指腸・嚢胞ドレナージを行い良好な経過を得たので報告する.症例は27歳,男性.ハンマーで腹部を強打され受傷し,腹腔内出血・遊離ガス像を認めたため緊急手術となった.膵はSMV直上で完全断裂しておりIIIb型膵損傷を呈していたため膵空腸吻合術(Letton-Wilson法)を施行し,また右半結腸の広範な穿孔・挫滅があり右半結腸切除術を施行した.術後,膵液瘻みられたが保存的治療で軽快し第40病日に退院となった.受傷より約3カ月後に上腹部痛が出現し,諸検査で離断した尾側膵から発生した膵仮性嚢胞と診断した.内視鏡的に十二指腸球部後壁の隆起部を針状ナイフで穿刺し貯溜液のドレナージを図った.その後,症状は軽決し嚢胞も消失し,処置後約1年が経過した現在も再発はみられず,膵機能も正常である.内視鏡的十二指腸・嚢胞ドレナージ術は小さな嚢胞でも壁に圧排像として認められれば確実に穿刺できる.また,今回のように膵管と交通性のある症例に対しても内瘻化が容易であり,膵液瘻を作りにくいなどの利点を有しており,膵損傷後の仮性嚢胞の治療に簡便にまた安全に施行でき有効な治療手段と考えられた.A patient in whom pancreatic pseudocyst after the surgery for traumatic pancreatic injury was successfully treated with endoscopic cystoduodenostomy (ECD). A 27-year-old man beaten on the abdomen with a hammer underwent emergency surgery due to intraperitoneal hemorrhage and free gas development. Pancreatojejunostomy (Letton-Wilson technique) was performed because the pancreas completely ruptured just above the superior mesenteric vein was diagnosed as type IIIb pancreatic injury. Right hemicolectomy was performed because of the extensive perforations and crush of the right side of the colon. A pancreatic juice fistula observed postoperatively was resolved with conservative therapy, and he was discharged on the 40th disease day. Epigastric pain developed about three months after he was injured. Examinations resulted in the diagnosis as pancreatic pseudocyst occurring from the caudal side of the ruptured pancreas. The fluid pooled in the pseudocyst was drained by endoscopically puncturing the elevated site on the posterior wall of the duodenal bulb with a needle knife. Then, all associated symptoms were resolved and the pseudocyst disappeared. Since then, he has been followed for about one year without recurrence, with his pancreatic function being normal. Endoscopic cystoduodenostomy (ECD) can reliably puncture even a small cyst when it is expanded on the wall. It has other advantages that it can easily change a fistula to an internal fistula even in cases with the communication to the pancreatic duct, such as the present case, and that it is unlikely to produce a pancreatic juice fistula. Therefore, ECD is considered easy, safe, and effective for treating pseudocyst after pancreatic injury