増大傾向を示す胃神経鞘腫に対して腹腔鏡下胃部分切除が有効であった1例

A case of gastric schwannoma resected by laparoscopic partial gastrectomy

◆要旨：患者は64歳，男性．近医にて慢性C型肝炎の経過観察中に施行された上部消化管内視鏡で，胃体上部大彎に径3cmの粘膜下腫瘍を指摘され，当院に紹介され，腹腔鏡下胃部分切除術を行った．

　胃神経鞘腫の本邦報告例290例において,占居部位は胃体下部小彎後壁側にやや多い傾向を認め，腫瘍径の平均は6.0cmであった．一方，胃神経鞘腫における悪性の頻度は4.8～10.0％ともいわれ，腫瘍の大きさと核分裂像の有無を判定基準とする報告もあるが，経過観察例7例のdoubling time（DT）を検討したところ，良悪性の間に違いはなかった．胃神経鞘腫に腹腔鏡下手術が行われた8例の検討では，胃内型，胃外型にも施行され，部位の偏りもなかった．術前診断が困難で，両悪性の鑑別が難しい本症の場合，低侵襲で診断治療が行える腹腔鏡下手術を積極的に考慮し，経過観察する場合は慎重を要する．

　A 64-year-old man underwent gastric endoscopy during follow up of chronic hepatitis C. He was found to have a gastric submucosal tumor（3 cm in diameter）at the greater curvature of the upper part of the gastric body. The patient underwent laparoscopic partial gastrectomy. Pathological examination revealed spindle-shaped cells arranged in palisades. The specimen was positive for S-100 protein. Benign schwannoma was diagnosed histologically. The medical records of 290 patients with gastric schwannoma reported in the Japanese literature were reviewed. The mean age of the patients was 58.9 years, and the male-to-female ratio was 2 : 3. The most common symptoms included abdominal pain, abdominal tumor, hematemesis and melena. Recently, cases of gastric schwannoma found during medical checkup have increased. Gastric schwannomas tend to occur on the posterior wall of the lesser curvature of the middle to upper gastric body, and the mean diameter of the reported tumors was 6.0 cm. The malignancy rate of the gastric schwannoma was reported to be 4.8～10.0％, its criteria was the diameter and number of mitosis. In observing the doubling time（DT）of 7 cases reported in the Japanese literature, there were no differences in DT between benign and malignancy. It is difficult to state that the speed of progression is a sign of malignancy. At present, a clear treatment policy has not been established. If diagnosis is difficult preoperatively, laparoscopic surgery should be considered since this tnmor conld have malignant potential.