3）超音波内視鏡からみた深達度診断

Endoscopic Ultrasonography for Patients with Esophageal Cancer

要旨　食道表在癌の深達度診断では細径プローブによる内視鏡超音波検査（EUS）が最も客観的な情報を提供するが，良好な画像を得る必要があり，症例ごとに工夫を要す．手技として単純な食道内貯水法が簡便であるものの，食道蠕動を生じさせない工夫が必要である．ソフトバルーン法は理論を知ることによりどの部位でも容易に施行でき，食道壁層構造の変化に的を絞って検査すれば有用性が高い．上皮下リンパ組織の増生や微小浸潤の判定などは困難で，EUS像各層と各組織との対応にもなお議論がある．しかし，まず固有筋層，粘膜下層を同定し，粘膜下層上縁の層が粘膜筋板の情報を表すと考えれば食道表在癌の深達度診断は比較的容易であり，実際的でもある．

　The most objective diagnostic information about tumor invasion is obtained, if clear images are shown, by endoscopic ultrasonography using a high frequency ultrasound thin probe in patients with superficial esophageal cancer. Although the simple water-infusion method is the easiest technique, induction of esophageal peristalsis should be avoided to obtain good images. The soft balloon method is relatively easy and applicable throughout the whole of the esophagus, and provides clear images of the esophageal wall structure. However, it could happen that subepithelial lymphoid hyperplasia and microinvasion of the tumor might not be diagnosed correctly. In the clinical diagnosis, firstly, the proper muscle layer and the submucosal layer should be identified and then the muscularis mucosal layer can be identified as the surface layer of the submucosa. Diagnosis of depth of tumor invasion is actually based on the fast of the destruction or preservation of the muscularis mucosa.