進展範囲・深達度診断に苦慮した胃体部 "潜在linitis plastica型癌"の1例

"Latent Linitis Plastica" Gastric Cancer Difficult to Diagnosis for Spread and Depth, Report of a Case

　症例は50歳，男性．人間ドックの胃内視鏡検査で，胃体上部大彎の褪色域に浅いびらん性病変を有し，同部位の生検にて低分化腺癌と診断された．食道胃接合部から幽門前庭部では，送気による膨らみは良好である顕著な萎縮性胃炎であった．胃内視鏡色素撒布検査では，褪色域は比較的境界が明瞭な表層拡大型Ⅱc病変を呈しており，深達度は主に粘膜内癌で粗大顆粒状部位では粘膜下層までの浸潤と診断した．噴門側胃切除を施行するも術中，迅速標本にて肛門側断端陽性であり，幽門側胃切除を追加し胃全摘術を施行した．病理組織学的所見では，癌の粘膜面露出はⅡc面に一致していたが，Ⅱc病変を中心により広範囲な粘膜下層から漿膜下層までの浸潤をみる4型胃癌であった．胃体部の低分化型の表層拡大型Ⅱc病変の診断時には，常に“潜在linitis plastica型癌”を念頭に置き，胃壁の変化などを注意深く検討することが極めて重要であることを再認識させられた症例であった．

　A 50-year-old man was admitted to our hospital for a health check up. Endoscopic findings revealed a small erosion at the greater curvature of the middle gastric body. The wall of the gastric body had good expansion in this area. We diagnosed the lesion as super spreading Ⅱc. Biopsied specimens taken from the lesions showed poorly differentiated adenocarcinoma. The dye endoscopic picture showed a depressed lesion extending in the greater curvature of the body. When proximal gastrectomy was carried out, it revealed cancer cells in the anal wedge in the frozen section. Additionally total gastrectomy was carried out and histopathological examination revealed poorly differentiated adenocarcinoma (Type 4) 8×6 cm in size. The microscopical picture of the body showed invasion to the subserosa. We consider that this case is highly interesting for differential diagnosis of an advanced gastric cancer (Type 4), as opposed to a superficial spreading IIc lesion which was especially difficult to establish.