[1] Kanagawa Childrens Med Ctr, Dept Surg, Minami Ku, Yokohama, Kanagawa 2328555, Japan
[2] Kanagawa Childrens Med Ctr, Dept Pathol, Yokohama, Kanagawa 2328555, Japan
[3] Kushiro Rosai Hosp, Dept Surg, Kushiro, Hokkaido, Japan
[4] Kushiro Rosai Hosp, Dept Oral & Maxillofacial Surg, Kushiro, Hokkaido, Japan