Acoustic schwannoma: Radiosurgery planning. There is a heterogeneously enhancing left cerebellopontine angle cistern mass with extension into the internal auditory canal, which measures up to approximately 25 mm. The tumor also contains scattered foci of susceptibility effect likely related to chronic microhemorrhages. There is no significant mass effect upon the adjacent parenchyma. There is no evidence of acute infarct. There are mild nonspecific scattered foci of high T2 signal in the cerebral white matter. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits, skull, and mastoid air cells are grossly unremarkable. There are scattered paranasal sinus secretions. There is a right occipital scalp lipoma that measures up to 6 mm in thickness.
Pre-treatment planning MRI demonstrates a left vestibular schwannoma that measures up to approximately 25 mm. 