1. From the Department of Pediatric Surgery, University Children’s Hospital Basel (F-MH, DvS), Basel, Switzerland, and Central Pediatric Tumor Registry, Department of Pathology, University of Kiel (DH), Kiel, Pediatric Surgery, DRK-Klinik Siegen (DB), Siegen and Pediatric Oncology, University Hospital Homburg/Saar (NG), Homburg/Saar, Germany