H. pylori既感染者に生じた腺窩上皮型胃癌の1例

Foveolar-type Gastric Carcinoma in a Patient with a History of Helicobacter pylori Infection, Report of a Case

要旨●患者は80歳代，男性．胆管炎の治療時に，胃内に隆起性病変を認め精査となった．通常観察では萎縮粘膜を背景に胃体上部前壁に径30mmの粗大な隆起性病変を認め，色素撒布観察で表面は乳頭状構造を呈した．NBI拡大観察では病変内部の微小血管構築像は軽度の口径不同を認め，胃型腺腫（幽門腺腺腫）を疑いESDを施行した．切除標本の病理組織学的検索では，腺窩上皮に類似する細胞異型に乏しい腺管の乳頭状増殖を認め，腫瘍の大部分はMUC5AC陽性で，MUC6は背景粘膜のみ陽性であった．病理組織学的所見よりHelicobacter pylori既感染者に生じた腺窩上皮型胃癌（WHO分類ではfoveolar-type adenoma）の診断に至った．

　An 80s-year-old man diagnosed with cholangitis underwent esophagogastroduodenoscopy, which revealed an elevated lesion in the stomach. In white light images, a 30-mm large, elevated papillary lesion was found on the anterior wall of the upper gastric body in the atrophic mucosa, and the lesion surface showed a papillary structure with indigo carmine dye. Magnifying narrow-band imaging showed a mildly irregular microvascular pattern with a demarcation line. With a suspicion of pyloric gland adenoma based on appearance, endoscopic submucosal dissection was performed. Histopathological findings of the resected lesion showed papillary growth of the glandular ducts with poor cellular atypia similar to the foveolar epithelium. Majority of the tumor was positive for MUC5AC, and MUC6 was rendered positive only in the background mucosa. Hence, a diagnosis of foveolar-type gastric carcinoma（World Health Organization classification：foveolar-type adenoma）was established in a patient with a history of Helicobacter pylori infection.