多彩な内視鏡像を呈した早期胃腺扁平上皮癌の1例

Early Adenosquamous Carcinoma of the Stomach, Report of a Case and Review of the Literature

要旨　患者は52歳の男性．検診で胃の異常を指摘された．胃X線検査では前庭部の大彎側に約4cmの陰影欠損像を認めた．内視鏡検査では，同部位になだらかな隆起の上に更に一段と高い隆起を伴う腫瘍性病変を認めた．隆起の本体は大小不整な粗大結節で，結節と結節の間が薄い白苔に覆われ，びらんと出血を伴っていた．隆起とびらん部からの生検は高分化型から中分化型管状腺癌であった．摘出標本の病理診断では0-Ⅰ＋Ⅱc＋Ⅱa，大きさ30×25×6mm，腺扁平上皮癌で深達度はsmであった．早期の胃腺扁平上皮癌はまれで，わが国では4例の報告があるにすぎない．早期症例の集計および組織分類の問題点について文献的考察を行い報告した．

　The patient, a 52-year-old man, was admitted due to abnormality of the stomach. Endoscopy showed a protruded lesion arising from an elevated area in the gastric mucosa in the greater curvature of the gastric antrum. The surface of this lesion was uneven and areas of erosion were also observed on it. Biopsy specimen taken both from the elevated as well as the depressed portion showed well differentiated adenocarcinoma. The patient was operated on and the surgical specimen showed a Ⅰ ＋ Ⅱa ＋ Ⅱc type cancer measuring 30 × 25 × 6 mm in the greater curvature of the antrum. Histologically, the lesion was diagnosed as adenosquamous carcinoma and the depth of invasion was limited to the submucosa. The patient was doing well four years postoperatively, although lymph node metastasis was found to be positive during the operation.

　Adenosquamous carcinoma of the stomach is a relatively rare type of cancer in Japan with less than two hundred cases reported in the literature. This special type of gastric cancer is seldom found at an early stage and there has been only 14 such cases reported. The proposed histogenesis and clinical features of the disease are discussed in this report.