内分泌細胞癌への分化を伴い，リンパ節転移を来した0-I型早期胃癌の1例

Early Gastric Cancer Consist of Well Differentiated Tubular Adenocarcinoma with Solid Type Carcinoma Showing Neuroendocrine Differentiation, Report of a Case

要旨　患者は80歳代，女性．他院の上部消化管内視鏡検査にて早期胃癌が疑われ，当院へ紹介となった．胃X線造影検査で胃体中部小彎後壁に径25×22mm大の隆起病変が認められた．内視鏡検査では胃体中部小彎後壁に境界明瞭な隆起病変が認められた．表面は平滑で，びらん形成は認められず，NBIおよび色素内視鏡観察でも，深部浸潤を示唆する所見は認められなかった．内視鏡的切除の病理組織学的所見で，高分化管状腺癌主体であるが，病変深部において充実性に増殖する低分化な癌巣が存在し，粘膜下層への浸潤（SM2：590μm）と静脈侵襲，リンパ管侵襲が認められた．追加の外科的切除を実施し，1群リンパ節への転移が認められた．追加で実施した免疫染色（chromogranin-A，synaptophysin，CD56）にて充実性に増殖する低分化な癌巣は内分泌細胞癌と診断した．最終的な病理診断はearly gastric cancer，Type 0-I，tub1 with neuroendocrine differentiation，pT1（SM2：590μm），ly1，v2，N1，M0，Stage IBであった．

　80-year-old women visited our hospital to receive treatment for the early gastric cancer.

　X-ray examination showed a protruded lesion 2cm in diameter on the posterior wall of the middle portion of the stomach. Endoscopic findings showed a type 0-I lobular lesion with a smooth surface, and no signs of submucosal invasion. Endoscopic resection（ESD）was carried out without complication. Histopathological examination showed a well differentiated tubular adenocarcinoma with a poorly differentiated tubular adenocarcinoma, and also showed submucosal invasion, lymphatic invasion, and vascular invasion. Additional surgical resection was performed, and histopathological examination showed a regional lymph node metastasis. Immunohistological examinations（chronogranin-A, synaptophysin, CD56）showed neuroendocrine differentiation in the deep layer of the early gastric cancer which caused lymphatic invasion and vascular invasion. Final histopathological diagnosis was described as early gastric cancer, 0-I, tub1 with solid type carcinoma showing neuroendocrine differentiation, pT1（SM2 : 590μm）, ly1, v2, N1, M0, Stage IB.