興味深いEUS像と発育進展を呈したEBV陰性リンパ球浸潤胃癌の1例

EBV（Epstein-Barr Virus）-negative Gastric Carcinoma with Lymphoid Stroma Showing Interesting Findings of EUS and Tumor Progression, Report of a Case

要旨●患者は80歳代，男性．検診の上部消化管X線造影検査で異常を指摘され近医を受診し，上部消化管内視鏡検査を施行された．胃前庭部に腫瘍性病変を指摘され，生検で中分化型腺癌が検出されたため，精査目的で当院へ紹介となった．上部消化管内視鏡検査では，胃前庭部小彎に，健常粘膜に覆われた立ち上がりがなだらかな粘膜下腫瘍様の周囲隆起を伴う，不整な陥凹性病変を認めた．超音波内視鏡検査では，第2層は比較的低エコーで，下方に凸の形態を示し，第3層には境界明瞭な低エコー腫瘤を認め，第2層との境界は不明瞭だった．診断的治療を目的として，内視鏡的粘膜下層剝離術を施行した．病理組織学的には，0-IIc型，carcinoma with lymphoid stroma，pT1b2（SM2），ly（＋），v（−）であり，追加治療として腹腔鏡下幽門側胃切除術が行われた．局所遺残はなかったが，リンパ節転移を認めた．EBV（Epstein-Barr virus）の関連は認められなかった．

　A-82-year-old male visited our hospital, for further examination and treatment for gastric tumor pointed out by EGD（esophago-gastro-duodenoscopy）at another clinic, which was observed moderately differentiated adenocarcinoma histopathologically by biopsy. EGD revealed a submucosal tumor-like protrusion located on the lesser curvature of the gastric antrum with an irregular depression in the center of the tumor. EUS（endoscopic ultrasonography）showed a thickened second layer and a well-defined boundary hypoechoic mass located in the third layer. The patient underwent endoscopic submucosal dissection for total biopsy. The histopathological examination showed the carcinoma with lymphoid stroma negative for EBER in situ hybridization. Because lymphatic invasion was observed, additional distal gastrectomy was performed. Histopathologically, carcinoma has metastasized to lymph node.