Barrett食道癌の超音波内視鏡診断

Endoscopic Ultrasonography in the Diagnosis of Barrett's Esophageal Cancer

要旨　Barrett食道癌の深達度診断におけるEUSの診断能について検討した．高周波数細径超音波プローブでは，粘膜筋板から粘膜下層が線維化の影響で層構造の分離が不明瞭であることが多い．食道腺や脈管などが混在することで不均一に描出され，腫瘍との境界も不鮮明になりやすく，T1a-SMM/LPMとT1a-DMMの鑑別，T1a-DMM/SM1の診断は難しかった．SM2/SM3の診断能は比較的良好であった．周囲の健常部から腫瘍部へとプローブを動かして，層構造の変化をとらえる必要がある．リニア型EUSは腺上皮レベルにとどまる粘膜癌の描出には限界があるが，粘膜下層深部癌の深達度診断は良好であった．先端バルーンによる圧排で深く読みすぎる傾向があるので注意を要した．

　We undertook this study to determine whether EUS is useful in the diagnosis of the depth of invasion of superficial Barrett's esophageal cancer. The high-frequency miniature ultrasonic probe revealed a poorly demarcated wall structure due to fibrosis at the muscularis mucosae and sumucosal layer. The intermingling of esophageal glands and vessels resulted in a poorly demarcated border of the tumor. It was difficult to precisely differentiate between T1a-SMM/LPM and T1a-DMM and to distinguish T1a-DMM/SM1. The diagnostic rate of SM2/SM3 is relatively high. Scanning the layer structure continuously at the marginal area to the tumor area is needed to obtain a correct diagnosis of the tumor depth. Linear-type EUS is of limited value for the assessment of mucosal cancers remaining within the glandular epithelium, but were able to accurately estimate the depth of invasion of submucosal tumors. Diagnosis using EUS tended to over-reading due to compression by the balloon attached at the ultrasonic probe.