粘膜下腫瘍様形態を呈した胃神経周膜腫（perineurioma）の1例

Gastric Perineurioma with Subepithelial Tumor-like Appearance, Report of a Case

要旨●患者は50歳代，女性．検診の上部消化管X線造影検査で異常を指摘されたために内視鏡検査を施行したところ，胃穹窿部に病変を認めた．病変は粘膜下腫瘍様隆起で，頂部は陥凹し，発赤調を呈していた．生検では診断に至らず，内視鏡的粘膜切除術を行った．病理組織学的所見では，粘膜表層から粘膜下層にかけての結節状病変で，紡錘形から類円形の腫瘍細胞の増殖を認め，小型の類円形核と淡明な胞体から成る紡錘形細胞が毛細血管を中心にして，渦巻き状に増殖していた．免疫組織化学染色でGlut-1陽性，claudin-1部分的陽性，EMA，S-100蛋白，CD34，αSMAは陰性であり，以上より胃神経周膜腫（perineurioma）と診断した．

　Gastrointestinal endoscopy was performed in a 50-year-old female for the purpose of screening. A small, elevated lesion with subepithelial tumor-like appearance was found at the gastric fornix. A depression was noted at the top of the lesion, and the depressed area looked reddish in color, having the appearance of a submucosal tumor at the gastric fornix. Biopsies were taken but the diagnosis was not definitive. Therefore, endoscopic mucosal resection was performed as a therapeutic diagnosis（total biopsy）. Histologically, proliferation of bland spindle cells with ovoid-to-elongated nuclei and indistinct cytoplasm was observed. The tumor cells tended to be located around vessels in whorls of striking appearance. Immunohistochemical staining revealed that the spindle cells were positive for Glut-1 and Claudin-1 but were negative for EMA, S-100 protein, CD34, and SMA. Thus, this lesion was diagnosed as a gastric perineurioma.