To review basic information about medulloblastoma in children. To list the MRI and CT features of medulloblastomas. To discuss the differential diagnosis of posterior fossa tumors based on imaging findings. To present the current knowledge about the correlation between the imaging findings and the molecular subgroups of medulloblastoma.

Medulloblastma (MB) is a highly malignant (WHO grade IV), primitive cerebellar tumor of neuroectodermal origin [1,2]. It is the most common malignant brain tumor in children and accounts for approximately 30-40% of childhood posterior fossa tumors [1,3]. Medulloblastoma has a moderate male sex predilection (1,5:1) and tends to occur in younger children, with majority of cases being diagnosed in patients ≤10 years old [3-5]. The 2007 World Health Organization classification of tumors of the central nervous system (CNS) used histology to classify medulloblastomas, differentiating variants...

Imaging features in CT and MRI Medulloblastomas arise in the cerebellum and hence in imaging studies present as masses located in the posterior fossa (Fig. 1). Majority of tumors lie in the midline and involve cerebellar vermis or vermis and cerebellar hemisphere (Fig. 2 and 3); isolated involvement of the hemisphere is less commonly observed (Fig. 4) [2,10-12]. Besides presenting as round or polycyclic masses, pediatric medulloblastomas rarely can also have a very nodular appearance, which is characteristic of the MBEN histological variant (Fig. 5)....

MRI and, to a much lesser extent, CT are useful tools in the diagnosis, staging and treatment planning of medulloblastomas, as well as in monitoring for the disease recurrence.

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