術前に早期胃癌と診断したが漿膜下層浸潤を有する進行胃癌であった1例

Advanced Gastric Cancer Invasion into the Subserosal Layer with Preoperative Depth Diagnosis of Early Gastric Cancer, Report of a Case

要旨●患者は60歳代，女性．貧血を主訴に潰瘍を伴う未分化型癌の診断で当院を受診した．EGDで胃体中部後壁に陥凹性病変を認め，早期胃癌，0-IIc型，cT1b2（SM）N0M0と診断し，幽門側胃切除＋D2郭清を行った．病理組織学的には粘膜内に低分化腺癌と印環細胞癌が増殖し，粘膜下層以深では高度の線維性間質を背景に癌細胞が漿膜まで散在性に浸潤していた．脈管侵襲陽性で進行胃癌（por2>sig），pT4a（SE）Ly1V1N0と最終診断された．本症例は早期癌類似進行胃癌であり，術前の深達度診断が難しかった．術前内視鏡検査でT1b2〜MPと診断された陥凹性病変において，早期胃癌であれば深読み，進行胃癌であれば浅読みの是正にEUSが適していると報告があり，EUSを考慮する必要があった症例と言える．

　A female patient in her 60s previously visited a hospital with a complaint of anemia. She was diagnosed with undifferentiated gastric cancer with an ulcer and was then referred to our hospital for treatment. Upper gastrointestinal endoscopy in our hospital revealed a depressed lesion on the posterior wall of the middle gastric body. She was diagnosed with early gastric cancer, 0-IIc, cT1b2（SM）N0M0, and underwent distal gastrectomy with D2 lymph node dissection. Histological assessment revealed poorly differentiated adenocarcinoma and signet-ring cell carcinoma that proliferates in the mucosa. Cancer cells were diffusely infiltrating into the subserosal layer with a background of highly fibrous stroma in deeper submucosa layers. Lymphovascular invasion was positive, and the final diagnosis was advanced gastric cancer（por2>sig）, pT4a（SE）Ly1V1N0. This case was an early cancer-like advanced gastric cancer, and preoperative depth diagnosis was challenging. Reportedly, endoscopic ultrasonography（EUS）is suitable for preventing early gastric cancer overestimation and advanced gastric cancer underestimation in the depth of depressed lesions diagnosed as T1b2 to MP by preoperative endoscopy. The accurate assessment of the depth in this case by EUS remains unclear, but it should have been considered.