1. Department of Neurosurgery, University of Duisburg-Essen, 45147 Essen, Germany
2. Department of Neurosurgery, University Hospital Erlangen, 91054 Erlangen, Germany
3. Cushing’s Support and Research Foundation, Plymouth, MA 02360, USA
4. Department of Neurosurgery, Ev. Hospital Oldenburg, 26121 Oldenburg, Germany
5. Department of Women’s and Children’s Health, Uppsala University, Akademiska Sjukhuset, SE-751 85 Uppsala, Sweden