1. Service d’Hémato-Oncologie Pédiatrique, Hopital Trousseau, Paris Registre des Histiocytoses Centre de Référence des Histiocytoses, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France;
2. Hémato Oncologie Pédiatrique, Centre Hospitalier Universitaire (CHU) de Montpellier, Montpellier, France;
3. Department of Pediatric Hematology Oncology, Erasmus MC–Sophia’s Children’s Hospital, Rotterdam, The Netherlands;
4. Direction Recherche et Innovation, Centre Hospitalier Régional Universitaire (CHRU) Montpellier–Centre Administratif André Benech, Montpellier, France;
5. Pediatric Hematology Oncology, Ospedale microcetemico, Cagliari, Italy;
6. Pediatric Hematology Oncology, Azienda Sanitaria Provinciale, Ragusa, Italy;
7. Pediatric Hémato Oncology, CHU, Limoges, France;
8. Pediatric Hémato Oncology, CHU, Rennes, France;
9. Pediatric Hémato Oncology, CHU, Grenoble, France;
10. Pediatric Hematology Oncology, Universitets Hospital of Aarhus at Skejby, Aarhus, Denmark;
11. Pediatric Hémato Oncology, Hopital Jean De Flandre, CHU, Lille, France;
12. Pediatric Hematology Oncology, The Hospital for Sick Children, Toronto, ON, Canada;
13. Department of Women’s and Children’s Health, Karolinska Institute, Karolinska Univeristy Hospital, Stockholm Sweden; and
14. Department of Pediatric Oncology, Emma Children's Hospital/Academic Medical Center, Amsterdam, The Netherlands