• Etiology: small round blue cell tumor
  • Imaging: well defined, homogenous, enhancing inferior medullary velum mass, hydrocephalus
  • CT: dense
  • MRI: T1+T2 isointense, restricted diffusion
  • Complications: CSF spread seen 30% of time at presentation – indistinct folia / sulci on T1, leptomeningeal enhancement, sugar coating of cord / drop metastases
  • Clinical: among older children + adults, can originate off midline such as from Foramen of Lushka

Radiology Cases of Medulloblastoma

MRI of medulloblastoma in the posterior fossa
Axial (above left), sagittal (above middle) and coronal (above right) T1 MRI with contrast of the brain shows a heterogeneously enhancing mass centered in the fourth ventricle which extends into the right cerebellar hemisphere. Axial T2 MRI (below left) shows the mass to be solid and on diffusion weighted imaging (below right) the mass demonstrates diffusion restriction.
MRI of medulloblastoma
Sagittal T1 MRI without (left) and with (right) contrast of the brain shows a hypointense signal mass filling and distending the fourth ventricle that enhances homogeneously.