Brainstem lesion and post operative changes status post choroid plexus papilloma resection. There are postoperative findings related to suboccipital craniotomy. There is a persistent lobulated enhancing mass within the inferior portion of the fourth ventricle that measures up to 23 mm. There is confluent T2 hyperintensity in the posterior medulla, pons, and medial portions of the cerebellum, as well as scattered patchy areas of intrinsic T1 hyperintensity, enhancement, and susceptibility effect along the surgical approach and margins. There is a prior right transfrontal ventricular catheter track with surrounding T2 hyperintensity, susceptibility effect, and enhancement. There is a left transfrontal ventricular catheter that terminates in the third ventricle, slightly indenting the right thalamus. Artifact related to the surgical hardware otherwise obscures surrounding anatomy. There is no appreciable interval change in size of the ventricular system, which does not appear to be particularly dilated. There is a persistent left cerebral convexity extra-axial fluid collection that measures up to 3 mm in thickness associated with prominent smooth, diffuse dural enhancement. There is no evidence of acute cerebral infarction. There is a 6 mm wide arachnoid cyst anterior to the anterior temporal pole. There is a retention cyst in the left maxillary sinus. There is an apparent disconjugate gaze.
1. Postoperative findings in the posterior fossa with residual fourth ventricular choroid plexus tumor with probable vasogenic edema in the surrounding cerebellum and brainstem, as well as scattered areas of blood products, hemostatic material, and probable granulation tissue along the surgical approach, but no evidence of an acute territorial infarct.2. Unchanged appearance of the shunted ventricular system.3. Persistent left cerebral convexity extra-axial fluid collection that measures up to 3 mm in thickness associated with diffuse dural enhancement reaction.