胃の平滑筋芽細胞腫（Leiomyoblastoma）の3例

Three Cases of Leiomyoblastoma of the Stomach

　1960年，Martinら¹⁾が，核を取り囲む透明帯が存在する特異な細胞形態をとる胃の平滑筋肉腫をmyoid tumorと初めて記載し，さらに，1962年にStout²⁾は，いわゆる胃筋腫とは異なり，筋原線維を有せず，円形または多角形の細胞からなり，核周囲透明帯が存在する胃腫瘍を変型平滑筋芽細胞腫（bizarre leiomyoblastoma）と名付けることを提唱した．

　本邦においては，1965年に久保ら³⁾が3例の本腫瘍を報告して以来，胃のleiomyoblastomaの報告は8例を数えるのみである．

　In 1962 Stout reported 69 cases of what he named “bizarre leiomyoblastoma” of the stomach. The characteristics of this neoplasm he mentioned were that it had no myofibril and consists of round or polygonal cells in which nucleus were surrounded by clear zone.

　Lavin reported 26 cases and Tallqvist reported 10 cases of such a gastric neoplasm, but in Japan there have been only eight since the first three cases reported by Kubo in 1965.

　We have experienced three such tumors, one on the body of the stcmach, another on the angulus and the third on the antrum. The local histologic features of these tumors were as follows :

　The clear zone surrounding the nucleus were observed in all three cases. Regarding the cellular type, two cases were of mixed type, consisting of both the round and myofibrils. In two cases the tumor grew in intragastric pattern and the one case showed both extragastric and intragastric pattern. The tumor surface was ulcerated in two cases and one case had a gastric ulcer away from the tumor.

　Malignancy can be detected by mitotic rate but in no case was mitosis noted. All the patients are well now one, two and four year after operation respectively.