巨大食道粘膜下腫瘍に対し，消化管内視鏡下の局注を併用して胸腔鏡下核出術を施行した1例

A case of thoracoscopic enucleation for a large esophageal submucosal tumor using endoscopic local injection to the submucosal layer

◆要旨：症例は41歳，男性．健診の胃透視で食道粘膜下腫瘍を指摘され，当科紹介となった．境界明瞭な6.0×2.5cmの腫瘍で，精査の結果，平滑筋腫または神経鞘腫が疑われた．腫瘍径は大きいが，機能温存を目的として胸腔鏡下腫瘍核出術の方針とした．術中，腫瘍と粘膜層との境界の判別が困難だったため，消化管内視鏡下に色素を混じた局注を粘膜下層に行うことで，核出術が施行可能となった．術後経過は良好だった．平滑筋腫の病理診断であった．巨大食道粘膜下腫瘍に対する核出術は手技困難であり報告は少ないが，本例では粘膜下層への局注を併用することで，胸腔鏡下核出術が安全に施行可能となった．

　A 41-year-old man underwent esophagography during a medical examination and was found to have a 6-cm large esophageal submucosal tumor（SMT）. The tumor was located on the anterior aspect of the middle thoracic esophagus, and leiomyoma or schwannoma was suspected. Although the tumor was large, we performed thoracoscopic enucleation to preserve esophageal function. During the operation, it was difficult to distinguish the tumor from the mucosa; therefore, we performed a local injection in the submucosal layer with an upper gastrointestinal endoscope. The resected specimen was a 7.5×3.0×1.5-cm solid tumor diagnosed as a leiomyoma. No postoperative complications were found. Thoracoscopic enucleation for esophageal SMTs is common; however, it is difficult to prevent intraoperative injuries during surgical manipulations of large tumors. We managed to resect a large SMT using a local injection to the submucosal layer, which is similar to the endoscopic submucosal dissection technique. This technique would be suitable for large esophageal SMT, because it allows for the tumor to be resected easily and safely.