Mediastinal Germ Cell Tumor Exhibiting a Discrepancy between Tumor Markers and Imaging: A Case Study oleh Kei Takenaka, Toru Mukohara, Chihoko Hirai, Yohei Funakoshi, Yukiko Nakamura, Naoko Chayahara, Masanori Toyoda, Naomi Kiyota, Tomoo Itoh, Hiroshi Yokozaki, Hironobu Minami