小腸gastrointestinal stromal tumor（GIST）の1例

Large Gastrointestinal Stromal Tumor of the Small Intestine, Report of a Case

要旨　患者は47歳，男性．左下腹部痛にて近医を受診し，腹部超音波検査および腹部CTで腹腔内腫瘤を指摘され入院した．小腸X線検査では小腸は前右側へ圧排され，回腸に瘻孔様のバリウムの突出を認め口側腸管には漏斗状の狭窄を伴っていた．腹部MRIでは小腸と連続し管外性に発育した分葉状の腫瘤が描出された．術中所見では腫瘍は管外性に発育し，口側および肛門側小腸が捻転していた．腫瘍は腸間膜対側に付着した最大径14cmの管外性の腫瘤で，割面は白色調を呈し，散在性に壊死，変性を伴っていた．病理組織学的には大きな核を有する紡錘形細胞が束状に増生し，強拡大で50視野中5個の核分裂像を認めた．腫瘍細胞はc-kit陽性，CD34陰性，α-SMA陽性，S-100陰性であった．以上よりgastrointestinal stromal tumor，smooth muscle typeと診断した．

　A47-year-old man was admitted to our hospital because of lower abdominal pain. Abdominal ultrasonography, computed tomography and magnetic resonance imaging revealed a large, multi-cystic tumor in the left lower abdomen. Double-contrast radiography of the small intestine showed a fistulous barium fleck in a torturous and stenotic segment of the ileum. Macroscopically, there was an extrinsic ileal mass measuring14cm in its largest diameter. Because of the large size of the tumor, the ileal segment was strangulated. Histological examination revealed the tumor to be composed of spindle cells having high cellularity and frequent mitotic figures. The tumor cells were positive for c-kit and CD34. They were also positive for α-SMA and negative for S-100protein.

　Based on these finding, the tumor was diagnosed as a malignant gastrointestinal stromal tumor of the smooth muscle type.

　1) Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan