Rarest of the rare: Chordoid glioma infiltrating the optic chiasm.

Background: Chordoid glioma is a rare brain tumor typically located within the anterior third ventricle. It is a well-circumscribed, non-infiltrative tumor that grows as a mass within the ventricle.

Case Description: We present the case of a 50-year-old woman with a chordoid glioma located in the anterior third ventricle. Unusually, MRI revealed an enlarged optic chiasm. Histological sampling of the chiasm revealed tumor invasion.

Conclusion: Involvement of the optic apparatus is generally thought to be an imaging feature that can be used to distinguish chordoid gliomas from optic/hypothalamic gliomas. This case provides the first reported exception to this dogma.