随伴IIb病巣として横這型癌が存在し範囲診断困難であった分化型早期胃癌の1例

Early Papillary and Tubular Gastric Cancer Accompanied with Crawling Type Cancer Whose Horizontal Margin Was Difficult to Diagnose Accurately

要旨●患者は70歳代，男性．自然除菌後の胃体上部後壁に，一部境界不明瞭な20mm大の発赤扁平隆起性病変とその周囲に平坦発赤域が散在していた．扁平隆起した主病変部分はNBI拡大内視鏡でVEC patternを呈し乳頭腺癌を疑った．その周囲の発赤域は概ねLBC（light blue crest）を伴う形状均一なvilli様構造で腸上皮化生と診断した．内視鏡的切除標本では主病変部分は主に乳頭腺癌・管状腺癌から成り，深達度pT1b（SM2），脈管侵襲陽性であった．その周囲には随伴IIb病巣として横這型癌が存在し側方断端陽性であった．追加外科的切除標本では癌の遺残，リンパ節転移は認めなかった．横這型癌は，非全層性発育によりNBI拡大内視鏡診断が困難な場合もあり，陰性生検も時に併用し慎重な範囲診断が求められる．

　A man in his 70s was referred to our hospital for further examination of gastric lesions following spontaneous eradication of H. pylori. Esophagogastroduodenoscopies identified a red, flat, elevated lesion 20mm in size with partially unclear borderline, and some flat peripheral red areas. The elevated lesion revealed a VEC pattern with NBI（narrow band imaging）-magnified endoscopy, diagnosed as papillary adenocarcinoma. Furthermore, most flat red areas revealed uniform villous-like structures with light blue crest, diagnosed as intestinal metaplasia. Pathological diagnosis of ESD（endoscopic submucosal dissection）specimen revealed papillary and tubular adenocarcinoma with SM2 and lymphatic invasion in the main elevated lesion. Crawling-type adenocarcinoma was observed in the flat red areas, and the horizontal margin was evaluated as positive. An additional operative specimen revealed no residual cancer and lymphatic metastasis. Crawling-type gastric adenocarcinomas often exhibit non-transmucosal growth, which causes difficulty in the precise diagnosis of the horizontal margin. Therefore, careful observation is necessary during their diagnoses, and collection of surrounding biopsy samples should be considered, if necessary.