Headache, nausea, preoperative planning for craniotomy for tumor resection. Examination is limited to sequences for operative planning and intraoperative navigation. Again seen is an enhancing, predominantly solid fourth ventricular mass measuring approximately 3.6 x 4.2 x 4.2 cm in the AP, transverse, and craniocaudal dimensions. Mass demonstrated restricted diffusion on prior study. Again noted is obstructive hydrocephalus with dilated lateral, third, and upper aspect of the fourth ventricles similar to prior. Periventricular T2 hyperintensity is consistent with transependymal CSF flow. Distended optic nerve sheaths also again seen. No additional foci of parenchymal or meningeal enhancement are appreciated. No midline shift or uncal herniation. Mild inferior cerebellar tonsillar herniation again seen. Major flow-voids are preserved. Mucosal thickening in the maxillary sinuses, right worse than left again noted. Calvarium and extracranial soft tissues are otherwise unremarkable.
Examination for operative planning again demonstrates a fourth ventricular mass which is favored to represent a medulloblastoma. Associated obstructive hydrocephalus again seen.