深達度診断が難しかった表在食道癌の1例

Superficial Esophageal Cancer with a Difficult to Assess Depth of Invasion, Report of a Case

要旨　患者は70歳代の男性で，胸部中下部食道に存在する中央が陥凹した隆起性病変である．通常観察ではやや軟らかい感じがあったが，隆起が目立ち，NBI拡大像では，隆起部分を中心に新生血管と考えられる太い血管が分岐蛇行していた．EUSでもSM層への浸潤所見が認められたため，総合的に深達度SM2以深と診断した．ESDを施行後，組織学的検査を行うと，粘膜筋板までの浸潤で深達度はT1a-MMであった．通常観察で感じたやわらかさが実際の深達度を表現しており，深達度診断の難しさを改めて感じさせられた症例であった．

　A male in his seventies was shown to have a protruded lesion with central depression on the right wall of the middle thoracic esophagus. Protrusion of the tumor was outstanding, although the tumor was suggested not to be so hard on the white light endoscopy. Magnifying endoscopy with NBI（narrow band imaging）revealed the tumor vessels with branched vessels on the protruded portion. EUS（endoscopic ultrasonography）also showed a hypoechoic mass lesion invading submucosal layer. So the depth of tumor was diagnosed as SM2 in a comprehensive manner. Histological assessment after ESD（endoscopic submucosal dissection）showed esophageal squamous cell carcinoma pT1a-MM, ly0, v0, pHM0, pVM0, with size being 14×10mm. So from this misdiagnosed case, it could not help saying that some cases have difficulty to make a precise diagnosis of tumor depth.