Female, 4 months old, previously healthy, with new vertical metastatic mass noted in both eyes, with suprasellar lesion seen on imaging. A lobular mass is evident centered in the suprasellar cistern measuring 51 x 38 mm in the axial plane (image 5 series 2301), and up to 23 mm in the coronal plane (image 8 series 2201). The lesion is slightly T1 hypointense to brain parenchyma and uniformly T2 hyperintense. The lesion is solidly enhancing on all postcontrast sequences, though on the early acquired postcontrast images (series 1901), the lesion shows a marginal rind of hyperenhancement which eventually equilibrates with internal enhancement on more delayed images. The lesion contains no internal susceptibility to suggest the presence of blood products or mineralization. The lesion does not diffusion restrict.The lesion encases the ICAs and the M1 and A1 segments, and may potentially narrow these vessels, though flow voids are seen compatible with preservation of patency. The lesion protrudes superiorly, elevating the thalami and frontal lobes as well as deforming the contour of the third ventricle. The lesion extends laterally to slightly displace the left medial temporal lobe. Posteriorly, the lesion extends into the prepontine cistern, particularly on the left where there is some slight mass effect on the left cerebral peduncle.The orbital structures are unremarkable. The lesion engulfs the optic chiasm and optic tracts which are therefore not evaluated. The lesion extends down and may compress the pituitary gland to some degree, though it is distinct from the pituitary gland. Both the anterior and posterior portions of the pituitary gland are visualized and appear otherwise unremarkable.The remainder of the brain demonstrates normal morphology and signal characteristics. The pattern of white matter myelination is appropriate for age. No evidence of restricted diffusion or any parenchymal edema is seen. No acute intracranial hemorrhage is detected. The ventricular system, despite deformation of the third ventricle by tumor, is not dilated. No additional pathologic intracranial enhancement is seen.
A lobular, solid enhancing tumor is evident centered on the suprasellar cistern with mass effect upon the thalami, inferior frontal lobes, left medial temporal lobe and left cerebral peduncle. The lesion encases the terminal ICAs, as well as the A1 and M1 segments, with possible vascular narrowing but with preserved patency.Given the morphology and location of the lesion, a glioma of the optic chiasm or hypothalamus is favored, with pilocytic astrocytoma as the most common histology. By location, craniopharyngioma and germinoma would also be in the differential, but these are considered less likely based on other imaging features.