T1 axial pre gad T1 axial post gad T1 coronal post gad

Diagnosis: Metastatic leptomeningeal neuroectodermal carcinomatosis

Metastatic disease to the CNS most commonly presents as a parenchymal mass, followed by leptomeningeal then dural involvement. Approximately 10% of CNS metastases involve the leptomeninges. Leptomeningeal carcinomatosis is typically diffuse rather than nodular and usually involves the basilar cisterns. The most likely etiology for this appearance is metastatic disease. Carcinoma of the lung and breast as well as melanoma are the top considerations. This was a rare neuroectodermal primary. Secondary lymphoma may also be in the differential. Sarcoidosis is a good thought, particularly if there is enhancement of the pituitary infundibulum which wasn't shown. Other etiologies of leptomeningeal enhancement include meningitis, post operative change, and inflammation from subarachnoid hemorrhage. Related Cases

Sarcoid Leptomeningeal carcinomatosis