隆起型食道扁平上皮癌の深達度診断―超音波内視鏡を中心に

Endoscopic Ultrasonography for Diagnosis of Infiltration Depth of Elevated Esophageal Cancer

要旨　食道表在癌の深達度診断には通常内視鏡，拡大内視鏡，超音波内視鏡，食道X線造影などが用いられる．通常観察でほぼ平坦にみえる病変の深達度は，通常観察と拡大観察で十分に診断できる．一方，明らかな隆起を認める病変は粘膜下層に浸潤していることがあり，超音波内視鏡により有用な情報が得られる可能性がある．高周波数の細径プローブを用いて観察すると，食道壁は通常9層に分離される．表在癌の深達度診断には，3層から5層の高エコー層の評価が重要で，腫瘍エコーにより3層の不整や中断がみられ，4層には明らかな変化がみられないものをMM/SM1癌の診断し，腫瘍エコーが3層を断裂させ4層から5層に及ぶものをSM2/SM3癌と診断する．

　The diagnosis of tumor infiltration depth is crucial for selecting the optimal treatment strategy for esophageal cancer. Infiltration depth of esophageal cancer is usually predicted by conventional endoscopy, magnified endoscopy, ultrasonography and Barium study. Conventional endoscopy and magnified endoscopy are commonly used for prediction of infiltration depth of flat esophageal cancer. For elevated esophageal cancer, which may have submucosal invasion, ultrasonography provides useful information for the diagnosis of infiltration depth. The esophageal wall is usually divided into nine layers by using a high frequency miniature probe. Diagnosis of MM/SM1 cancer is made when the third layer is irregular or absent in the tumor echo and that of SM2/SM3 cancer is made when the fourth and fifth layers are irregular or absent in the tumor echo.