家族性多発性GIST（gastrointestinal stromal tumor）の1例

Familial and Multiple Gastrointestinal Stromal Tumors, Report of a Case

要旨　症例は60歳代の女性．検診で異常を指摘され，近医で上部消化管内視鏡（GIS）が施行された．胃隆起性病変が認められたため精査治療目的で当院に入院となった．入院時のGISで体上部前壁に約3cmの粘膜下腫瘍（SMT）があり，その他に穹窿部から胃角にかけて小型のSMTが多発していた．超音波内視鏡で第4層から連続する内部エコー均一な腫瘍として認められた．腹部超音波で左側腹部に約30mmの腫瘤があり小腸腫瘍が疑われた．開腹所見で胃は粘膜面のみならず漿膜側にも無数の小結節が認められ，小腸にはTreitz靱帯から約10cmと100cmの部位に壁外性発育する腫瘤がみられた．胃全摘および小腸腫瘤摘出術を施行した．病理組織学的所見ではHE染色では紡錘形で柵状に配列する腫瘍細胞がみられ，KIT，CD34が陽性であった．また胃固有筋層内にKIT陽性のCajal介在細胞の過形成が無数に存在し，さらに生殖細胞系列にc-kit遺伝子変異も認められたことから家族性多発性GISTと診断した．本疾患は現在までに15家系の報告しかなく，貴重な症例と考え報告した．

　A 60-year-old woman was admitted to our hospital because of an abnormality found by barium study of her stomach. Gastroduodenoscopy revealed a submucosal tumor on the lesser curvature of the upper gastric corpus, and multiple small submucosal tumors in the area from the fundus to the lesser gastric corpus. Abdominal ultrasound showed that a hypoechoic mass adjoined the jejunum measuring 30mm in size. A wedge resection of the mass in the jejunum and total gastrectomy were performed. Immunohistochemical examination showed that the tumor cells were spindle-shaped and stained positively for both KIT and CD34. Diffuse hyperplasia of the interstitial cell of Cajal (ICCs) was also found in the remaining wall of the stomach which had been considered normal macroscopically. In addition, we found germ line mutation in c-kit lesions. According to these date, this case was diagnosed as familial GISTs.