fig3

Figure 3. Typical magnetic resonance imaging features of group 3 medulloblastoma. Post-contrast axial T1-weighted (A) and corresponding T2-weighted (B) images show a midline posterior fossa mass filling the IVth ventricle with “cotton-wool” pattern of enhancement. Post-contrast sagittal T1-weighted image (C) shows the inferior location of the primary tumor with widespread leptomeningeal dissemination in the brain and spine