[1] Hop Nord St Etienne, Dept Pediat Oncol & Hematol, St Etienne, France
[2] Ctr Leon Berard, Dept Radiol, F-69373 Lyon, France
[3] Hop Necker Enfants Malad, Dept Neuropathol, Paris, France
[4] Hop Necker Enfants Malad, Dept Pediat Neurosurg, Paris, France
[5] Inst Gustave Roussy, Dept Pediat Oncol, Villejuif, France
[6] Bristol Royal Hosp Sick Children, Dept Pediat Oncol, Bristol, Avon, England