Reason: multifocal AA. s/p RT/TMZ+TMZ. History: AA. Expansile and infiltrative T2 hyperintense lesion involving the left pons, midbrain and thalamus without enhancement or diffusion restriction is unchanged in size and distribution. Extension into the left medial temporal lobe with mass effect on the left hippocampus is similar to the prior exam. Increased T2 signal along the left lateral cerebellar hemisphere is also unchanged. There are 2 small T2 hyperintense cysts along the medial margin of the center lesion at the approximate imaging level of the hippocampus, measuring up to 3 mm (series 11, images 19 and 20) which are increased in size since the prior exam, and not definitely visualized on the baseline exam.Postsurgical changes including right cerebellar tissue loss appear similar to the prior exam. Several scattered foci of susceptibility, particularly along the right cerebellar hemisphere appear similar to the prior exam. There is no abnormal intracranial enhancement. 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, paranasal sinuses, and scalp soft tissues are grossly unremarkable.
Nonenhancing mass involving the left pons, midbrain and thalamus is unchanged in size, however there are tiny 3 mm cysts at the margins of the lesion which have emerged and are minimally increasing in size, of uncertain clinical significance. Close attention is recommended on follow-up.