Usefulness of neuroimaging and immunohistochemical study for accurate diagnosis of chordoid glioma of the third ventricle: A case report and review of the literature.

BACKGROUND: Chordoid glioma of the third ventricle is a rare neuroepithelial tumor characterized by a unique histomorphology within the third ventricular region, but with radiological and histopathological features mimicking benign lesions such as meningioma. We report a case of chordoid glioma of the third ventricle and suggest a useful indicator for accurate diagnosis. CASE DESCRIPTION: A previously healthy 46-year-old woman was admitted to our hospital with mild headache. Neuroimaging revealed a large tumor measuring approximately 18 mm in the suprasellar region, and perifocal edema in the optic tract and internal capsule on magnetic resonance imaging. Laboratory findings revealed no pituitary dysfunction including diabetes insipidus. Gross total resection of the tumor was performed by the interhemispheric translamina terminalis approach. Histological findings revealed nests of regular epithelioid cells with large nuclei and abundant eosinophilic cytoplasm within myxoid stroma. Immunohistochemical studies demonstrated diffuse cytoplasmic expression of glial fibrillary acidic protein (GFAP) and CD34, and strong nuclear staining for thyroid transcription factor 1 (TTF-1). We, therefore, histologically classified the tumor as chordoid glioma of the third ventricle. Headache improved immediately postoperatively, and follow-up neuroimaging after 12 months showed no signs of recurrence. CONCLUSIONS: Chordoid glioma of the third ventricle is a very rare tumor that is difficult to diagnose on routine neuroimaging. Accurate diagnosis requires detailed analysis of neuroimaging and immunohistochemical studies using CD34 and TTF-1 staining.