 There is a soft tissue mass centered on the planum sphenoidale measuring 15 x 11 mm on series 4 image 10, and 19 mm on series 7 image 7. This mass abuts the optic chiasm and is isointense to brain on T1 weighted images and minimally hyperintense on T2/FLAIR images. Although difficult to visualize on prior CT, it is retrospectively present and similar in size. There is an apparent increased CSF signal in the mildly expanded sella representing either an empty sella or possibly a cystic mass within the sella. This is not well evaluated on this noncontrast exam which is not tailored to evaluate the sella or the skull base. There is mild prominence of the lateral and third ventricles as well as the sulci, and a relatively normal sized fourth ventricle, less disproportionate to sulci as compared to the prior exam. There is persistent moderate soft tissue crowding at the foramen magnum with a somewhat pointed morphology of the cerebellar tonsils extending up to 7 mm below the foramen magnum. There is focal prominence of extra-axial space posterior to the superior cerebellar tonsils representing new cisterna magna versus retrocerebellar cyst. There is no acute infarct, mass effect or midline shift.There is decreased abnormal T1 signal in the posterior superior aspect of the C4 vertebral body.
1.A 15 x 11 x 19 mm planum sphenoidale extraaxial mass which at least abuts the optic chiasm. Further evaluation with sella/skull base MRI without and with IV contrast is recommended (if not contraindicated). While this lesion presumably represents meningioma, given history of breast cancer, metastatic lesion is not entirely excluded although considered to be less likely.2.Prominent CSF signal in the lower aspect of the sella may represent partial empty sella or an inferior pituitary cystic mass. This can be further evaluated on follow-up MRI.3.No definite evidence of normal pressure hydrocephalus. Findings consistent with diffuse age-related volume loss.4.Findings consistent with Chiari I malformation.5.Decreased abnormal T1 signal in the posterior superior aspect of the C4 vertebral body may represent possible degenerative change although metastatic lesion cannot be excluded. Further evaluation with dedicated cervical spine imaging or bone scan is recommended.