癌性リンパ管症を伴い上皮下腫瘍を形成した胃癌の1例

Gastric Cancer Forming a Subepithelial Tumor with Lymphangiosis Carcinomatosa, Report of a Case

要旨●患者は70歳代，男性．健診でCEA高値を指摘され精査目的のため当科へ紹介され受診となった．EGDではSMT様隆起の肛門側に白色調の不整形陥凹を認め，0-IIa＋IIc型早期胃癌と診断した．SMT様隆起のNBI拡大観察では，頂部粘膜の窩間部に不整な血管拡張・蛇行所見を認めたため生検を施行した．腺窩上皮直下の粘膜層に低分化腺癌を認めたため，胃全摘術を施行した．病理組織学的診断では，moderately differentiated tubular adenocarcinoma，pType 1，pT4a（SE），55×35×8mm，（tub2≫por），gastrointestinal type，HER2（0），intermediate，INFc，Ly1c，V1cであった．本症例は，原発巣である0-IIa＋IIc型早期胃癌の形態を保ったまま上皮下に進展し，口側に癌性リンパ管症を伴って上皮下腫瘍を形成していた．SMT様隆起のNBI拡大観察から，腺窩上皮直下への癌の進展を診断できた症例を経験したので報告する．

　A 70-year-old man was referred to our hospital with a high CEA. Esophagogastroduodenoscopy revealed a faded, irregularly shaped depression on the anal side of the SMT（submucosal tumor）-like lesion, which was diagnosed as early gastric cancer type 0-IIa＋IIc. Magnifying endoscopy with narrow-band imaging of the SMT-like lesion revealed irregular vessels in the intervening part, and a biopsy was performed. A total gastrectomy was performed because a poorly differentiated adenocarcinoma found in the mucosal layer below the marginal crypt epithelium. The histopathological diagnosis was pType 1, 55×35×8mm³, pT4a（SE）, and tub2. The patient had a primary 0-IIa＋IIc type early gastric adenocarcinoma with intramucosal spread extending and forming a SMT-like lesion with lymphangiosis carcinomatosa on the oral side.