NBI併用拡大内視鏡が深達度診断に有用であった大腸側方発育型腫瘍の1例

Laterally Spreading Tumor Effectively Diagnosed by Colonoscopy Using Narrow Band Imaging with Magnification, Report of a Case

要旨　患者は80歳代，男性．便潜血陽性にて下部消化管内視鏡検査を施行したところ大腸腫瘍を指摘され，当院へ紹介され受診となった．当部門での内視鏡検査ではS状結腸に15mmのLST-NG（PD）を認めた．インジゴカルミン撒布下色素内視鏡検査にて一部境界明瞭な陥凹面を認めた．陥凹面のNBI併用拡大観察ではcapillary pattern Type IIIAであったが，クリスタルバイオレット染色下拡大観察ではV_I型高度不整pit patternを認めた．陥凹面が平坦で空気変形は良好であったことからSM浅層までの早期大腸癌と診断し，ESDを施行した．病理所見は粘膜内にとどまる高分化腺癌で治癒切除であった．

　An 80-year-old man was referred to our division for endoscopic treatment of a colonic tumor. Colonoscopy showed a 15mm-diameter LST-NG（pseudo-depressed type）in the sigmoid colon. NBI（narrow band imaging）with magnification colonoscopy revealed slightly irregular microvessels on the depressed area. Magnification colonoscopy with crystal violet staining demonstrated a type V_I high-grade pit pattern. Therefore, we assumed that there was submucosal invasion of the cancer, but it was difficult to clearly determine the level of invasion. We performed an endoscopic submucosal dissection to achieve en bloc resection. Pathological diagnosis of the resected specimen was well-differentiated tubular adenocarcinoma［tub1, pTis（M）, INFa, ly0, v0, pHM0, pVM0］.

　There was a discrepancy between the evaluations of the depth of cancer invasion performed using NBI and pit pattern on magnification colonoscopy.