内視鏡切除を施行した30mmの表層拡大型大腸sm癌の1例

Superficial Spreading Type Rectal Cancer with Submucosal Invasion Treated by Piecemeal Endoscopic Mucosal Resection, Report of a Case

要旨　患者は62歳，男性．全大腸内視鏡検査で，直腸S状部に径約30mm，周囲粘膜とほぼ同色調，表面はほぼ平滑，中央部に小結節状隆起を持つ不整形の丈の低い隆起性病変を認めた．X線では境界がほぼ明瞭で表面を細い溝で区切られた丈の低い病変として描出された．体腔内超音波検査では，中心の小結節部位に一致して，腫瘍エコーの第3層内への浸潤様所見を認め，sm浸潤が疑われたが，粘膜下に生理食塩水を局注すると第3層はきれいに分離し，小結節部位も挙上した．総合的に判断して内視鏡的切除可能と考えEMRを施行した．病理組織学的には小結節状隆起の部位でsm微小浸潤を来した高分化腺癌であった．

　A 62-year-old man underwent colonoscopy during a screening test. It revealed a flat elevated lesion about 30 mm in diameter with a small central nodule in the rectosigmoid region. Barium enema examination visualized the lesion as a flat elevated one with a clear margin in the rectosigmoid region. Intraluminal ultrasonography demonstrated a mass invading the midsubmucosa of the rectal wall. Ultrasonography after injection of saline, however, showed that the tumor was detached from the Submucosal layer. Based on assessment of the overall results, endoscopic resection was carried out in a piecemeal manner. Histological examination showed a well differentiated adenocarcinoma with minute invasion of the submucosal layer surrounded by lymphoid stroma. The portion of microinvasion corresponded well with the central nodule observed by endoscopy.