Breast cancer. There has been interval decrease in size and number of enhancing bilateral cerebellar lesions that are essentially leptomeningeal in distribution. The supratentorial compartment appears to be unremarkable. There is no evidence of intracranial hemorrhage or acute infarct. The ventricles and basal cisterns are unchanged in size and configuration with a mildly T1 hyperintense subcentimeter cystic nodule associated with the roof of the third ventricle. 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.
1. Interval decrease in the burden of leptomeningeal metastatic disease involving the cerebellum.2. Subcentimeter third ventricular colloid cyst.