1. Department of Neurosurgery, Baskent University School of Medicine, Ankara, Turkey.
2. Department of General Surgery, Baskent University School of Medicine, Ankara, Turkey.
3. Department of Neurosurgery, Baskent University Konya Training and Research Hospital, Konya, Turkey.
4. Department of Pathology, Baskent University School of Medicine, Ankara, Turkey.