Presentation
Acute left-sided blindness. Optic atrophy on clinical examination.
Patient Data
There is an eccentric circumscribed left suprasellar extra-axial mass lesion with dystrophic calcifications. There is expansion of the intracranial left optic canal, however normal optic foramen and no intra-orbital extension. There is enhancement post-contrast administration. The lesion is inseparable from the left A1 and M1 segments. There is no hyperostosis regionally. The sella turcica is expanded with a flattened pituitary gland and a posterior pituitary stalk.
The primary consideration is of a planum sphenoidal or olfactory groove meningioma, however, an aneurysm is difficult to exclude on this suboptimal post contrast study.
Features consistent with a planum sphenoidale meningioma, with involvement of the cisternal segment of the left optic nerve including optic chiasm. This is demonstrated by a T1 and T2 isointense mass, epicenter at the left planum sphenoidale.
There is homogenous avid enhancement post-contrast administration. No regional hyperostosis was detected.
There is a curvilinear extension and involvement of the cisternal segmental of the left optic nerve. Nodular involvement of the left optic chiasm. There is waisting at the level of the optic foramen, with no intraorbital extension of the meningioma. The left optic nerve does appear atrophic in comparison to the asymptomatic right-hand side, consistent with the history of total blindness left-sided.
There is otherwise normal intra-orbital enhancement post-contrast administration.
The optic foramen is non-expanded.
The meningioma appears inseparable from the proximal left A1 and M1 segments. No vascular encasement is however demonstrated, the vessels are eccentrically on the periphery of the lesion. No regional left ACA or MCA thrombosis was further identified.
There is mild regional mass effect with consequent appearance of an expanded sella turcica with a flattened pituitary gland and posteriorly displaced pituitary stalk.
Contrast-enhanced MR imaging of the brain is otherwise essentially normal. Time of flight MRA appears normal. No evidence of intracranial venous sinus thrombosis.
Case Discussion
The patient presented to the opthalmologist with a history of acute blindness. Clinical examination revealed left-sided optic atrophy and no other significant findings.
The CT brain study had a few technical issues. It was acquired on a bony protocol and hence appears grainy. The CT contrast administration was suboptimal too, one would have expected a much more avid enhancement post-contrast administration, especially in view of the MRI findings suggesting a meningioma. This also prevented the confident exclusion of an intracranial aneurysm on the post-contrast CT study.
Multiplanar and multiaxial MRI brain confirmed the left planum sphenoidale meningioma with optic nerve and optic chiasm involvement. A primary left optic nerve or optic chiasmatic meningioma and regional spread cannot be definitively excluded. However, there is a normal optic foramen and no intraorbital extension is present.
The sphenoid wing is normal rather than hyperostotic on both CT and MRI studies and suggests a sphenoid wing meningioma is possible but less likely. A posterior olfactory groove meningioma is also part of the differential and can be difficult to exclude especially if a large meningioma is detected at the time of presentation.