1. Department of Neurosurgery, Yaizu City Hospital, Yaizu, Shizuoka, Japan
2. Department of Pathology, Yaizu City Hospital, Yaizu, Shizuoka, Japan
3. Department of Pathology, Toranomon Hospital, Tokyo, Japan
4. Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan