Malignant gastrointestinal neuroectodermal tumor presenting with small intestinal obstruction: A case report oleh Makiko Sasaki, Mamoru Tanaka, Koki Asukai, Hiroki Koguchi, Yusuke Inoue, Mizuki Moriyama, Tetsuo Tsukahara, Takeo Kawahara, Eiji Hayashi, Yukinori Hattori, Izumi Hasegawa, Hiromi Kataoka