NBI拡大観察下にESDを行い，断端陽性となった分化型腺癌の1例

Moderately Differentiated Gastric Adenocarcinoma in Which a Positive Lateral Margin was Histopathologically Diagnosed Following Endoscopic Submucosal Dissection, Report of a Case

要旨●患者は60歳代，女性．胃X線検診にて異常を指摘され，当科へ紹介となり，受診した．上部内視鏡検査では，胃体下部大彎に約7mm大の不整形陥凹性病変を認め，生検でGroup 5（tub2）の診断であった．通常およびNBI拡大内視鏡を用いて，病変の範囲診断を行い，陥凹部のみ病変と認識しESDにて切除を行った．切除標本の病理組織学的検討で，陥凹部後壁側に高分化〜中分化腺癌の進展を認め，側方断端陽性となり追加手術を行った．粘液形質は胃型優位の胃腸混合型であった．癌表層部は腺窩上皮様の分化傾向を示し，範囲誤診の原因と考えた．通常内視鏡観察で病変の全体像を把握し，詳細なNBI拡大観察を行うことが重要である．

　A 60-year-old female was referred to our hospital for a detailed examination after an abnormality was noted in her stomach on X-ray. Upper endoscopy revealed an irregular, depressed lesion about 7 mm in diameter on the greater curvature of the lower gastric body, and it was diagnosed as a moderately differentiated adenocarcinoma on biopsy. After a detailed examination of the tumor margin using conventional and magnified endoscopy with narrow-band imaging（NBI）, endoscopic submucosal dissection was performed only for the depressed area. Histopathological examination of the resected specimen revealed well to moderately differentiated adenocarcinoma that had spread to the posterior area of the depressed lesion. Pathology revealed a positive lateral margin; therefore, the patient underwent additional surgery. The tumor was gastric-predominant mucin phenotype. We considered that a misdiagnosis of the tumor margin was causally related to surface differentiation similar to gastric foveolar of the cancer gland. Therefore, magnified endoscopy with NBI must be performed for a more accurate evaluation after an overview image of the cancer lesion is obtained using conventional endoscopy.