Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 3, 2011, pp. 469-471

Neurology India, Vol. 59, No. 3, May-June, 2011, pp. 469-471

Letter to Editor

Chordoid glioma of the third ventricle: A case report with review of literature

Mukul Vij¹, Sushila Jaiswal², Awadhesh Kumar Jaiswal³, Manoj Jain², Sanjay Behari³

¹ Department of Pathology, Global Hospital and Health City, Chennai, India
² Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow, India
³ Department of Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow, India

Correspondence Address: Mukul Vij Department of Pathology, Global Hospital and Health City, Chennai India mukul.vij.path@gmail.com

Date of Submission: 06-Feb-2011
Date of Decision: 06-Feb-2011
Date of Acceptance: 01-Apr-2011

Code Number: ni11135

PMID: 21743188

DOI: 10.4103/0028-3886.82740

Sir,

A 48-year-old male presented with gradual diminution of vision of 1 month duration and recurrent episodes of focal seizures involving right lower limb of 20 days duration. He became less communicative and developed bladder and bowel incontinence 4 days before admission. On examination, the patient was conscious, but preferring to sleep, and was following commands on coaxing. Cranial nerves and ocular fundi were normal. Tone on the right side was increased. There were no motor, sensory, or cerebellar deficits. His hematological and biochemical parameters were normal. Contrast computer tomography (CT) scan showed a mass lesion in the third ventricle. The tumor was isodense with homogenous enhancement [Figure - 1]a. Magnetic resonance imaging (MRI) revealed a mass lesion in the third ventricle, iso to hypointense in T1-weighted images and iso to hyperintense on T2-weighted images with homogenous contrast enhancement and perilesional edema [Figure - 1]b. Right pterional craniotomy and tumor decompression was performed through lamina terminalis. Intraoperatively, the tumor was yellowish, firm, and minimally vascular. Partial excision of the tumor was done. The patient had uneventful postoperative course and at follow-up of 10 months was doing well.

The tumor consisted of clusters and singly scattered oval-to-polygonal epithelioid cells with abundant eosinophilic cytoplasm having relatively uniform centric or eccentrically placed round-to-oval hyperchromatic nuclei and inconspicuous nucleoli with abundant extracellular pools of mucin [Figure - 2]a. Mitotic figures were not discernible. Occasional small foci of tumor showed sparse infiltrates of mature lymphocytes and plasma cells with Russell bodies. Alcian blue stain highlighted the background mucinous matrix [Figure - 2]b. Immunohistochemistry tests for the cell proliferation marker Ki-67, glial fibrillary acidic protein (GFAP), vimentin, CD-34, epithelial membrane antigen (EMA), pan cytokeratin, S100, neurofilament protein (NFP) and synaptophysin were performed. Immunohistochemistry tests for GFAP [Figure - 2]c, CD-34 [Figure - 2]d and cytokeratin (CK) [Figure - 2]e were positive within tumor cells. There was variable focal positivity for S100 and EMA [Figure - 2]f. Immunohistochemistry tests for NFP and synaptophysin were negative. The Ki-67 proliferation index was very low ( <1%). Based on these findings, a diagnosis of chordoid glioma (CG) of the third ventricle was made.

World Health Organization (WHO) defines CG as a non-invasive glial tumor of the third ventricle, located in third ventricle and histologically characterized by clusters and cords of epithelioid GFAP expressing tumor cells within variably mucinous stroma. ^[1] Although the incidence of CG cannot yet be evaluated because of its recent description, it seems to be an uncommon tumor.^[1],[2] The precise histogenesis of CG remains uncertain. Immunohistochemical positivity for GFAP and vimentin favors a glial origin. Histopathologic features of CG have been similar in all the reported cases: Clusters and cords of epithelioid cells embedded in a mucinous matrix with prominent lymphoplasmacytic infiltrates. ^[3],[4] Common immunohistochemical results include a low Ki-67 index; diffuse GFAP, vimentin, and CD-34 positivity; focal cytokeratin and EMA positivity; inconsistent S100 protein positivity; and negativity for neuronal markers (synaptophysin, NF, and NSE). Few cases, however, were surprisingly positive for NF and NSE. ^{[2],[3],[4],[5]}

From a histological point of view, the most difficult differential diagnosis is between chordoma and chordoid meningioma. The absence of bone infiltration and of physaliphorous cells (typical features of chordoma) and the lack of psammoma bodies, cellular whorls, and nuclear pseudoinclusions (common in meningioma) can help in making the diagnosis. Immunohistochemistry may be decisive. Meningioma is EMA positive and GFAP negative, and chordoma is positive for EMA, cytokeratins, and S100 and negative for GFAP. CG, on the other hand, is typically immunopositive with GFAP and CD-34, and, in some cases, focally positive with EMA, cytokeratins, and S100. ^{[1],[2],[3],[4],[5],[6]}

Although CG is considered to be a low-grade tumor, the anatomic origin in the rostral third ventricular region in close juxtaposition to hypothalamic structures increases the risk of surgical morbidity and mortality. Incompletely resected tumors continue to enlarge slowly, and some patients experience a poor outcome. ^[7],[8],[9] Gross total surgical resection, when possible, appears to be the treatment of choice, although, as noted, the proximity to vital central nervous system structures increases the possibility of significant morbidity.

References

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