Neuro-Ophthalmologic Features of Chordoid Glioma

Abstract

Chordoid glioma is a rare intracranial tumor typically arising in the third ventricle, particularly along the anterior aspect of the hypothalamic wall. We describe the clinical, neuroimaging, and pathologic factors of this neoplasm in a patient presenting with a chiasmal syndrome.

A 37-year-old man reported a 5-year history of progressive “hazy vision” in both eyes. He had no other systemic complaints and the remainder of his medical, social, family, allergy, and medication history was noncontributory. Visual acuity was 20/40 in the right eye and 20/50 in the left eye. Pupils were isocoric, and there was a right relative afferent pupillary defect. Anterior segment, intraocular pressure, and ocular motility examinations were normal, and automated visual field testing demonstrated a bitemporal hemianopia. Funduscopic examination showed mild bilateral temporal optic disc pallor. Optical coherence tomography showed global retinal nerve fiber layer (RNFL) thickness of 95 µm (right eye) and 93 µm (left eye) with papillomacular bundle RNFL dropout in each eye.

Magnetic resonance imaging (MRI) of the brain showed a lobulated, well-circumscribed enhancing mass 28 × 39 × 19 mm in the anterior–inferior third ventricle with displacement of neighboring structures (Fig. 1).

FIG. 1: Postcontrast axial (A) and coronal (B) magnetic resonance imaging demonstrates an enhancing mass in the anterior third ventricle and suprasellar region, splaying the cerebral peduncles and exerting mass effect on the infundibulum. T2 axial (C) and fluid attenuated inversion recovery (D) images show a cystic component to the tumor with signal changes in the medial temporal lobes, basal ganglia, hypothalamus, anterior thalami, and internal capsule.

The patient underwent craniotomy with subtotal resection of the tumor. Histopathologic findings included cords and clusters of eosinophilic epithelioid tumor cells with bland oval nuclei within a mucinous matrix with occasional lymphocytes and plasma cells (Fig. 2A, B). Tumor cells were positive for S100 protein pancytokeratin and glial fibrillary acidic protein (Fig. 2C). Rare tumor cells were positive for epithelial membrane antigen. Ki-67 labeling index was 5.0%. These features were consistent with World Health Organization grade II chordoid glioma.

FIG. 2: Histopathology of chordoid glioma. A. Within a myxoid background are clusters of epithelioid cells (hematoxylin and eosin, ×40). B. Epithelioid cells have round bland nuclei in a vacuolated basophilic stroma (hematoxylin and eosin, ×100). C. Glial fibrillary acidic protein (GFAP) highlights the cytoplasm of glioma cells (immunochemistry with 3,3′-Diaminobenzidine chromogen, GFAP antibody, ×40).

Six months later, visual acuity was 20/40 in the right eye and 20/60 in the left eye. Funduscopy revealed mild, bilateral temporal optic disc pallor, and MRI showed postoperative changes but without tumor recurrence.

Chordoid gliomas are rare tumors with both glial and chordoid characteristics. First described in 1998 by Brat et al (^1,2), subsequently they were classified as World Health Organization grade II in 2000 (^2–6). Chordoid gliomas demonstrate features of specialized ependymal differentiation and have a predilection for the third ventricle, particularly the anterior aspect of the hypothalamic wall. The collective features point to an anatomical origin from the vicinity of the lamina terminalis (⁷). They are slow-growing and noninvasive neoplasms and more commonly affect women with a mean age of 46 years (^2,4,6). Because chordoid gliomas typically arise from the anterior third ventricle, a majority of patients present with neuro-ophthalmic signs including loss of visual acuity, visual field defects, and papilledema (^2,4–7). Patients may also present with headache, memory loss, or endocrine symptoms (²).

Chordoid gliomas have nonspecific MRI features: isointense on T1 sequences, contrast enhancing, and hyperintense on T2 images (^2,4,6). These findings may cause diagnostic confusion with craniopharyngioma or pituitary adenoma. Some features that may distinguish chordoid gliomas include location in the anterior third ventricle, ovoid shape, hyperdense to gray matter on computed tomography, and uniform contrast enhancement by both intensity and density (⁸).

Treatment of chordoid gliomas often requires multiple modalities. Because of its proximity to the hypothalamus, aggressive surgery carries significant risk. Stereotactic radiosurgery with or without conventional radiation is believed to be superior to conventional radiation alone. Subtotal resection followed by stereotactic radiosurgery is another therapeutic option. Although chemotherapy has been used in some cases, it remains of unproven benefit. The overall postoperative morbidity has been reported up to 60% and mortality ranges between 28% and 32% (^4,9,10).