1. Department of Pediatrics, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
2. Department of Neurosurgery, Juntendo University Faculty of Medicine, Tokyo 112-8421, Japan
3. Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo 112-8421, Japan
4. Department of Pathology, Juntendo University Faculty of Medicine, Tokyo 112-8421, Japan