Lobulated 4th ventricular mass with cystic changes measuring 38x58x40 mm (AP*SI*transverse)
The mass is isointense to gray matter on T1 and T2 and demonstrates avid enhancement, not restricted on DW images, no extension through the foramen of Luschka or Magendie.
There is moderate dilatation of all ventricles with slight transependymal CSF flow, it causes pressure effect of surrounding cerebellar hemispheres, pons, medulla oblongata, and cerebellar peduncles (mainly middle) with intrinsic high signal in the pons, medulla oblongata & middle cerebellar peduncles (edema), but no invasion to surrounding brain parenchyma.
The differentials are choroid plexus papilloma, very unlikely other pediatric 4th ventricular tumors like ependymoma & medulloblastoma.