正常粘膜下に広範囲に側方進展した大腸SM癌の1例

Submucosal Rectal Carcinoma Spreading Widely Under the Normal Mucosa, Report of a Case

要旨　患者は60歳代，男性．主訴は便潜血陽性．大腸内視鏡検査で直腸Raに大きさ約10mm大の表面凹凸不整なIs病変を認めた．NBI拡大観察では不整な網目模様と間接的に不整なpitを認め，広島大学分類のC2，クリスタルバイオレット染色による拡大観察では，隆起の立ち上がりから頂部にかけてV_I型pit pattern（高度不整）であった．以上より深達度SM深部浸潤が疑われたが，直腸病変のため，total biopsy目的でESDを施行した．病理組織結果は，中分化管状腺癌，SM実測値4,900μm（表層より測定），脈管侵襲ly2，v3で，隆起部とその周囲の粘膜下層に脈管侵襲を伴って広範囲に浸潤し，一部，粘膜固有層内に逆行性に浸潤する像を認め，水平断端，垂直断端，いずれも陽性であった．

　A man in his sixties underwent a colonoscopy for the diagnostic purpose of occult blood stool. Conventional colonoscopy revealed a protruded lesion in the lower rectum. The tumor was 10mm in diameter, and the configuration was type Is. Magnifying colonoscopy with the NBI（narrow band imaging）system showed thick and irregular vessels. Magnifying colonoscopy with crystal violet showed V_I-high type pit pattern from the border to the top of the protruded lesion. Based on these findings, this tumor was diagnosed as a deeply submucosal invasive carcioma. ESD（endoscopic submucosal dissection）was performed for total biopsy. Pathologically, the protruded lesion was a moderately differentiated tubular adenocarcinoma with a depth of submucosal invasion（SM 4,900μm, from the surface of the tumor）, ly2, v3.

　It had invaded widely into the lower layer of the protruded lesion and the neighboring mucosa with vessel invasion, and reversely into the lamina propria mucosa.