1. Department of Surgical Pathology; Sapporo Medical University, School of Medicine; Sapporo Japan
2. Department of Diagnostic Pathology; Asahikawa Red Cross Hospital; Asahikawa Japan
3. Department of Neurosurgery; Asahikawa Red Cross Hospital; Asahikawa Japan
4. Department of Pathology; Tokai University, School of Medicine; Kanagawa Japan