Evaluate for residual posterior fossa tumor and possible spinal metastases: status post posterior fossa tumor resection. Brain: There are interval postoperative findings related to suboccipital craniotomy for resection of a posterior fossa tumor. There is residual non-enhancing extra-axial tumor in the right inferior fourth ventricle, cerebellopontine angle, right premedullary cistern, and the upper cervical spinal canal, which measures up to approximately 45 mm. There is associated mass effect upon the adjacent right cerebellar hemisphere, brainstem, and upper spinal cord. There is interval insertion of a right transfrontal ventricular catheter with high T2 signal and susceptibility effect surrounding the catheter in the right frontal lobe, as well as globular blood products surrounding the catheter in the right lateral ventricle and layering blood products in the bilateral occipital horns. There are areas of T2 hyperintensity and restricted diffusion in the medial cerebral hemispheres. The third and lateral ventricles are less dilated. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits, skull, paranasal sinuses, and scalp soft tissues are grossly unremarkable.Spine: Aside from the mass effect upon the right and posterior upper cervical spinal cord by the inferior extension of the posterior fossa tumor, the rest of the spinal cord appears intact, without discernible abnormal signal. There is no evidence of drop metastases within the spinal canal. The vertebral column alignment is within normal limits. The vertebral body and disc space heights are preserved. The vertebral bone marrow signal is unremarkable. There is no significant posterior disc herniation.
1. Interval partial resection of a tumor arising from the fourth ventricle with residual tumor in the right inferior fourth ventricle, cerebellopontine angle, right premedullary cistern, and the upper cervical spinal canal, measuring up to approximately 45 mm, and areas of acute ischemia along the medial cerebellar hemispheres bilaterally.2. Interval right transfrontal ventricular catheter insertion with decrease in size of the triventricular system, but complicated by mild right frontal lobe edema and scattered areas of intraventricular hemorrhage.3. No evidence of drop metastases within the spinal canal.