回盲弁にみられたIIa＋IIc型早期癌の1例

Early Cancer at the Ileocecal Valve, Report of a Case

要旨　患者は，81歳，男性．早期胃癌に対して幽門側胃切除術を施行して以来，定期観察中であった．約2年ぶりに下部消化管内視鏡検査（CF）を行ったところ，回盲弁上唇にIIa＋IIc様病変が認められた．バリウム注腸X線検査では，回盲弁上唇に不整形の淡いバリウム斑がみられた．生検結果では腺腫だったが，悪性を否定できず，手術を行った．術中内視鏡にて病変の全体像を確認し，回盲弁上唇に発生した早期癌，IIa＋IIc，深達度sm以深，と考え，第2群リンパ節郭清を伴う回盲部切除を施行した．その結果，深達度はmにとどまる高分化型腺癌だった．回盲弁から発生した表面陥凹型早期癌の報告例はなく，極めてまれと思われた．

　An asymptomatic 81-year-old man had been followed up regularly at our hospital since undergoing distal gastrectomy for early gastric cancer 13 years previously. At the last colonoscopy, performed 2 years after the previous examination, a shallow depressed lesion with a slightly raised margin was observed at the superior lip of the ileocecal valve. Barium enema demonstrated irregular barium flecks at the superior lip of the ileocecal valve. Although histological examination of biopsy specimens suggested tubular adenoma, we considered surgery to be warranted since malignancy could not be ruled out. At operation, endoscopic examination enabled the entire lesion to be visualized, revealing an early cancerous lesion with submucosal invasion. Ileocecal resection with regional lymph node dissection was therefore performed. Macroscopic classification was IIa＋IIc type and histological evaluation of surgical specimens demonstrated a well-differentiated adenocarcinoma confined to the mucosa. As the literature contains no similar reports, we have documented this rare case.