Female, 71 years old, with dizziness. Assess for metastases. History of breast cancer. Extensive thick, and in some areas nodular, leptomeningeal enhancement is evident throughout the cerebellar fissures with modest associated parenchymal edema. Leptomeningeal enhancement also coats the tectum.Supratentorially, scattered sulcal enhancement is seen, most notably along the medial and anterior right temporal lobe, and along the anterior left temporal lobe where the enhancement is more nodular and in contact with the overlying dura. Mild leptomeningeal enhancement is seen along the proximal sylvian fissures, within the interpeduncular cistern, along the fifth cranial nerves and seventh/eighth cranial nerves bilaterally, and questionably along the optic apparatus and sella.Parenchymal edema is most evident within the posterior fossa and in the left anterior temporal lobe. There is likely some effacement of the fourth ventricle, but elsewhere no significant mass effect is detected. The supratentorial ventricular system remains within normal limits for size.No evidence of significant intracranial hemorrhage is seen. No abnormal fluid collections are detected.
Extensive leptomeningeal enhancement is seen, most severely affecting the posterior fossa but with scattered areas supratentorially with involvement of several cranial nerves.Given the history of breast cancer, leptomeningeal carcinomatosis is felt to be the most likely underlying etiology.