Breast cancer metastasized to central nervous system. Since the brain MRI from November 2015, there are has been interval progression of supratentorial and infratentorial metastatic disease consisting of increase in size of existing lesions and interval appearance of several new lesions, with a total of approximately 20 intra-axial lesions. For example, a right cerebellar hemisphere lesion measures 8 mm in diameter, previously 4 mm, and there is a new 5 mm diameter right thalamus lesion. There is vasogenic edema associated with the lesions, but otherwise an unchanged background of mild periventricular white matter T2 hyperintensity, which may represent chronic small vessel ischemic disease. There are postoperative findings related to left parieto-occipital craniotomy without evidence of nodular enhancement to suggest tumor recurrence in this location. There is unchanged confluent white matter T2 hyperintensity in the treatment bed region. There is an unchanged subcentimeter enhancing lesion within the fundus of the right internal auditory canal. There is an unchanged developmental venous anomaly in the brainstem associated with punctate foci of susceptibility effect that likely represent cavernous malformations. There is unchanged mild encephalomalacia in the left cerebellar hemisphere. There is no evidence of acute infarct. The ventricles and basal cisterns are stable in size and configuration, with ex vacuo dilatation of the left lateral ventricle. There is minimal midline shift to the left. There is minimal fluid signal within the left mastoid air cells. There is mild mucosal thickening in the paranasal sinuses. The skull and extracranial soft tissues are unchanged.
1. Overall progression of intracranial metastatic disease since November 2015.2. An unchanged subcentimeter right internal auditory canal lesion may represent a vestibular schwannoma versus less likely a metastasis.3. Unchanged developmental venous anomaly in the brainstem associated with punctate foci of susceptibility effect that likely represent cavernous malformations.