Posterior fossa tumor assessment. Presented with neck pain and torticollis. There is a large mass filling the fourth ventricle and extending through its outflow tracts (especially the right foramen Luschka and foramen Magendie) into the right cerebellopontine angle as well as the upper cervical spinal canal posterior to the spinal cord down to lower C2 vertebral level. The mass is associated with obstructive dilatation of the lateral and third ventricles as well as transependymal CSF flow in the periventricular white matter. The mass has a largest axial diameter (as measured on image #7 of series #4 all 1) of 6.3 cm x 4.2 cm. Craniocaudally, as measured on image #98 of series #902, it measures maximally 5.8 cm. The mass is mildly T2 hyperintense and is T1-hypoointense (relative to gray matter) and shows only heterogeneous, predominantly peripheral contrast enhancement. The mass shows diffusion characteristics that are similar to gray matter. The mass displaces and partially encases the right posterior inferior cerebellar artery and its branches which are asymmetrically enlarged compared to the left side. It abuts and displaces the right intracranial vertebral artery as well. It deforms the brainstem and the cerebellar hemispheres but does not invade them. There is no sign of leptomeningeal metastasis. The dural venous sinuses and major intracranial arteries are patent. There is very minimal mucosal thickening/fluid in the paranasal sinuses and the right mastoid air cell. The orbits are unremarkable.
1.Fourth ventricular mass with extension into the right cerebellopontine angle and the upper cervical spinal canal is most compatible with ependymoma. Much less likely considerations include medulloblastoma and an exophytic juvenile pilocytic astrocytoma. 2.The mass causes obstructive hydrocephalus.3.Presurgical planning sequences were also performed as above.