Male, 42 years old, with history of right anterior skull base encephalocele, preoperative imaging. Correlating with findings on the same day CT, a lobular lesion is present centered on the left paramedian clivus with extension into the sphenoid sinus and minimally into the prepontine cistern. The lesion is T1 hypointense and markedly T2 hyperintense with some signal heterogeneity. The lesion does not enhance on postcontrast images.Although osseous structures are better assessed on prior CT, again no definite defect in the anterior skull base is seen. There are no areas of suspected meningeal or parenchymal herniation. Scattered mucosal thickening and/or secretions are redemonstrated in the paranasal sinuses.The signal characteristics and morphology of the brain are otherwise unremarkable. No evidence of restricted diffusion, edema or focal signal abnormality is seen. There are no findings to suggest acute intracranial hemorrhage or any abnormal extra-axial fluid collections. No pathologic intracranial enhancement is observed. A small right frontal developmental venous anomaly is noted incidentally. The ventricles are normal in size and morphology. A right suboccipital subcutaneous lipoma is redemonstrated.
1.A lobular, non-enhancing lesion is evident centered on the left paramedian clivus with extension into the sphenoid sinus and minimally into the prepontine cistern. Given the CT and MRI findings of this lesion, the differential diagnosis would include a notochordal remnant (ecchordosis physaliphora), as well as a neurenteric or developmental cyst. Lack of enhancement and absence of specific symptoms related to this lesion argue against chordoma or some other aggressive lesion, though this possibility is not entirely excluded.2.No evidence of any defect in the anterior skull base is seen. There are no findings to indicate herniation of meninges or brain parenchyma.3.Evaluation the brain is otherwise within normal limits.