IgG4-related disease presenting as a submucosal tumor of the stomach resected with laparoscopic endoscopic cooperative surgery: a case report oleh Taishi Yamane, Kojiro Eto, Takeshi Morinaga, Kazuki Matsumura, Kohei Yamashita, Ryuma Tokunaga, Kazuto Harada, Yukiharu Hiyoshi, Yohei Nagai, Masaki Iwatsuki, Shiro Iwagami, Yuji Miyamoto, Naoya Yoshida, Hideo Baba