異型上皮巣で覆われた胃脂肪腫の内視鏡的摘除例

Lipoma of Stomach Associated with Atypical Epithelium of Overlying Mucosa, Report of a Case

　胃体部に発生した亜有茎性の隆起性病変に対し，Ⅰ型早期癌を疑って内視鏡的ポリペクトミーを施行したところ，隆起の主体は脂肪腫でその表面粘膜は大部分が良悪性境界領域の異型上皮巣で占められていた．また，この異型上皮の一部には癌との鑑別が困難な高度の異型腺管がみられた．

　胃の脂肪腫と異型上皮巣がこのような形で共存した症例の報告はなく，文献的にみて，われわれの症例が本邦で初めての報告であると思われる．

　A case of gastric lipoma in a 52 year-old man is reported in which its overlying mucosa was accompanied by “atypical epithelium”. The patient was asymptomatic, and the lesion was incidentally found by routine x-ray examination of the stomach for his health care. Both radiologically and endoscopically, the lesion appeared as a semi-pedunculated polypoid lesion at the anterior wall of the lower body, and resembled either hyperplastic polyp or early carcinoma, Type Ⅰ.

　Biopsy showed glandular changes typical of “atypical epithelium”, but small foci suggestive of tubular adenocarcinoma were seen, which could be interpreted as Group Ⅳ. The patient refused surgery, so that it was decided to perform an endoscopic polypectomy.

　The polypectomy specimen showed on cut section a well-circumscribed lipoma, measuring 17×10×10 mm, lying in the submucosa, which was completely resected. Histologically, its overlying mucosa looked like that seen in the previous biopsy specimens. It was entirely covered with slightly elevated mucosa of “atypical epithelium”. Focal areas suggestive of adenocarcinoma, as evidenced by occasional formation of intaglandular budding and marked stratification of nuclei with loss of polarity. were superficially seen as well as transformed more typical areas of “atypical epithelium”, without no clear-cut demarcation between these two areas.

　One year follow-up with repeated endoscopic examinations showed no abnormalities. No similar case was to be found in the Japanese literature.