LST-NG（T1癌）—微小な陥凹を伴う0-IIa＋IIc型病変（LST-NG）の1例

A Case of a 0-IIa＋IIc Type Lesion（LST-NG） with a Diminutive Depressed Component

要旨●患者は70歳代，男性．上咽頭癌の精査目的で施行したPET-CTで結腸に異常集積を指摘され，大腸内視鏡検査を行った．横行結腸に30mm大の0-IIa＋IIc型病変（LST-NG）が認められた．病変中心部に厚みがみられ，頂部に1mmの白色の陥凹を認めた．陥凹部はJNET分類Type 3，pit patternはV_I型高度不整，陥凹周囲はJNET分類Type 2B，pit patternはV_I型軽度不整と診断した．陥凹部での粘膜下層深部浸潤は否定できないが，non-invasive patternのT1a癌と診断しESDを行った．病理組織学的には陥凹を含む厚みのある領域で，粘膜下層深部への浸潤を認めた．

　This report describes a male patient in his 70s evaluated for nasopharyngeal carcinoma. Positron emission tomography with computed tomography revealed an abnormal uptake in the colon. Colonoscopy detected a 30mm laterally spreading tumor-non-granular lesion in the transverse colon. This lesion had a thickened central area with a 1mm white depressed component at the apex. The depressed area was classified as Japan Narrow-Band Imaging Expert Team（JNET）type 3 with a V_I-type invasive pit pattern, and the surrounding area as JNET type 2B with a VI-type noninvasive pit pattern. Although the depressed area exhibited submucosal invasion, the lesion was judged as noninvasive and diagnosed as T1a carcinoma. Thus, endoscopic submucosal dissection was performed. However, histopathologically, the thickened region including the depressed area demonstrated submucosal deep invasion.