Chapter 3

Imaging Differential Diagnosis of Pediatric

CNS Tumors

3.1Explanatory Note

After termination of this book the new WHO-classification of central nervous system tumors has been published [9]. As a completely new classification system frequently based on genetic definitions and no longer purely on histology has been created some entities in the following chapters have been abolished and do no longer exist like “gliomatosis cerebri”. Others have been refined and are called now differently like “embryonal tumors with multilayered rosettes” (ETMR) for the former PNET.

“CNS embryonal tumor NOS” has to be used in the future for an AT/RT without the confirmation of the characteristic molecular defect.

As the present experience with the imaging characteristics of pediatric brain tumors is based on the last WHO-classification system published in 2007 only rarely experiences with some of the new entities like the genetically defined groups of MB exist. Further knowledge on imaging characteristics of the new entities will be acquired only in the future and has not yet been included in this book.

3.2Embryonal Tumors

Embryonal tumors primarily affect children and only rarely adults. They are derived from embryonal cells and comprise the most frequent highly malignant tumors in children, like MBs, primitive neuroectodermal tumors of the supratentorial compartment (cPNET), pineoblastomas, and atypical teratoid/rhabdoid tumors (AT/ RT). After the general PNET concept coined by the neuropathologist LB Rorke [10] it is now recognized that these tumors former uniformly called PNET are subdivided according to their localization [11]. The reason for this strategy among others is that they show differing results after treatment.

M. Warmuth-Metz, Imaging and Diagnosis in Pediatric Brain Tumor Studies, DOI 10.1007/978-3-319-42503-0_3