EMRで診断しえた4型を呈した低異型度分化型胃癌の1例

Extremely Well-differentiated Adenocarcinoma of the Stomach Presented with Borrmann Type 4, which was Diagnosed by Endoscopic Mucosal Resection（EMR）, Report of a Case

要旨●患者は60歳代，男性．201X年12月，早期胃癌に対して内視鏡的粘膜下層剝離術（ESD）を受けた．201（X＋1）年8月，前医のESD後経過観察の内視鏡で，胃体下部前壁に1cm大の褪色陥凹面を認めたが，生検の病理診断がGroup 1であったため，フォローアップとなった．半年ごとに上部消化管内視鏡検査（EGD）および1年ごとにCT検査が行われていたが，201（X＋6）年12月に病変の明らかな増大傾向を認め，当院に紹介となった．当院でのEGDでは，胃体下部前壁〜大彎に7cm大の4型の病変を認めた．発赤調の凹凸不整な粘膜と周囲に腫大・融合した皺襞を認めた．NBI拡大内視鏡検査では発赤した不整粘膜に一致して微小血管と表面構造の不整を認めたが，周囲粘膜との境界は不明瞭であった．病変に対して，腹腔鏡下幽門側胃切除術を施行した．切除標本による病理学的所見では，細胞・構造異型の乏しい腺管が漿膜下層まで浸潤する低異型度分化型腺癌であった．

　A male patient aged 60 years underwent endoscopic submucosal dissection for early gastric cancer in a hospital in December 201X. During a follow-up in August 201（X＋1）, a slightly depressed white lesion measuring 5mm in size was detected. The biopsy of the lesion showed Group 1, and the patient was instructed to undergo regular follow-up gastroscopy and computed tomography examinations twice in a year. In December 201（X＋6）, the size of lesion considerably increased than that observed in the first examination, and the patient was referred to our hospital. The gastroscopy examination in our hospital showed wall-thickening spreading from the anterior wall to the greater curvature of a lower body and folds, which were enlarged and fused at some point toward the lesion, consistent with the symptoms of limited Borrmann type 4 gastric cancer. The size was approximately 7cm. Narrow band imaging with magnification revealed irregular vessels, but the mucosal surface pattern was not remarkably irregular. We performed endoscopic mucosal resection and diagnosed well-differentiated adenocarcinoma. Laparoscopic pylorus gastrectomy was performed, and microscopic findings showed very mild atypia of tumor cells and glands, spreading mainly below the submucosal layer, which was consistent with the symptoms of gastric-type, low-grade, well-differentiated adenocarcinoma.