通常・色素内視鏡による早期胃癌深達度診断―組織型別検討を中心に

Depth Diagnosis for Early Gastric Cancer by Conventional and Chromo-Endoscopy

要旨　内視鏡的，あるいは外科的に切除された早期胃癌547病変（分化型癌/未分化型癌＝444病変/103病変，M～SM1癌/SM2癌＝485病変/62病変）の通常および色素内視鏡による深達度診断能を組織型別に検討した．分化型癌と未分化型癌において，深達度を正しく診断できた割合はそれぞれ90.1％，71.8％であった．分化型癌では浅読みが多く，深達度を迷う病変に対して診断的にESDを行っている背景が影響していると考えられた．未分化型癌は，分化型癌と比較して有意にUL（＋）の割合が高く，炎症や浮腫による粘膜下腫瘍様隆起，潰瘍瘢痕による線維化をSM深部浸潤所見と誤診する深読みが多いと考えられた．

　We evaluated depth diagnosis by conventional and chromo-endoscopy in 547 EGC（early gastric cancers）（differentiated-type/undifferentiated-type＝444/103, M-SM1/SM2＝485/62）according to their histological types. The percentages of the differentiated-type and undifferentiated-type EGCs which were correctly diagnosed were 90.1％and 71.8％, respectively. The depth of differentiated-type EGCs tended to be underestimated, because diagnostic endoscopic submucosal dissection was carried out for the lesions for whose depths were difficult to diagnose. In contrast, the depths of undifferentiated-type EGCs tended to be overestimated, because they significantly had ulcer findings compared with differentiated-type EGCs. Also, the margin elevation and fibrosis due to ulcer findings were sometimes misdiagnosed as the endoscopic findings indicative of deeper submucosal invasion.