Chordoid glioma is a rare tumor of the anterior third ventricle. It is only recently characterized and not typically included in the differential diagnosis of suprachiasmatic and third ventricular tumors. To date, 65 cases have been reported.[4
] Of these cases, all but one has been located within the anterior third ventricle.[3
Lesions commonly seen in this location include craniopharyngiomas, optic/hypothalamic gliomas, germ cell tumors, meningiomas, Rathke's cleft cysts, hamartomas, and pituitary macroadenomas. Imaging features that can help to distinguish chordoid gliomas from other lesions in this location include displacement of the infundibulum and involvement of the optic apparatus. Chordoid gliomas displace the infundibulum posteriorly. In contrast, Rathke's cleft cysts and tuber cinereum hamartomas displace the infundibulum anteriorly.[6
] Optic/hypothalamic gliomas typically involve the optic apparatus, whereas it is generally thought that chordoid gliomas are well circumscribed and do not involve or extend into the optic apparatus.[6
Surgical reports have consistently confirmed the lack of optic apparatus involvement observed on MR imaging. Ricoy et al
] described the presence of tumor in the retrochiasmatic space without attachment to the chiasm or surrounding structures. Pomper et al
] reported that tumor was absent from the optic apparatus. Pasquier et al
] described a case in which the tumor was contiguous with, but did not extend into, the optic chiasm. Grand et al
] reported that the tumor was not adherent to surrounding structures. Raizer et al
] described a tumor which was adherent to, but did not infiltrate, the optic chiasm. Lastly, Suh et al
] reported compression of the chiasm without tumor extension into the chiasm. Beyond the expected visual symptoms caused by a tumor in this location, there are no reports of tumor invasion into the optic apparatus.
Of the 65 reported cases of chordoid glioma, none have been shown to involve the optic chiasm. This is the first demonstration of a chordoid glioma that involves the optic chiasm on imaging with intraoperative confirmation. We thus propose that the presence of optic chiasm involvement should not be used as a feature to exclude chordoid glioma from the differential diagnosis of suprasellar/anterior third ventricular tumors.