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Table of Contents    
Year : 2012  |  Volume : 60  |  Issue : 1  |  Page : 131-132

An anaplastic ependymoma presenting as an intrinsic brainstem glioma

1 Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, Whitefield, Bangalore, India
2 Department of Pathology, Sri Sathya Sai Institute of Higher Medical Sciences, Whitefield, Bangalore, India

Date of Submission24-Dec-2011
Date of Decision28-Dec-2011
Date of Acceptance30-Dec-2011
Date of Web Publication7-Mar-2012

Correspondence Address:
Sumit Thakar
Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, Whitefield, Bangalore
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.93623

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How to cite this article:
Thakar S, Mohan D, Furtado SV, Ghosal N, Hegde AS. An anaplastic ependymoma presenting as an intrinsic brainstem glioma. Neurol India 2012;60:131-2

How to cite this URL:
Thakar S, Mohan D, Furtado SV, Ghosal N, Hegde AS. An anaplastic ependymoma presenting as an intrinsic brainstem glioma. Neurol India [serial online] 2012 [cited 2022 Sep 26];60:131-2. Available from: https://www.neurologyindia.com/text.asp?2012/60/1/131/93623


Primary extraventricular ependymomas are infrequent in the supratentorial [1] and infratentorial compartments. This report describes a primary intrinsic brainstem (BS) ependymoma without any involvement of the fourth ventricle. The tumor demonstrated features of an intrinsic BS mass and had exuberant ventral and lateral exophytic components, findings seen in the rare, ventrally exophytic BS glioma. [2]

A 15-year-old boy presented with diplopia and right-sided facial weakness since one month and holocranial headache since a week. Neurologic findings included papilledema, inter-nuclear ophthalmoplegia and right peripheral seventh cranial nerve paresis. Magnetic resonance imaging (MRI) showed a diffuse lesion in the ponto-mesencephalic region with intrinsic and symmetric exophytic cisternal components [Figure 1]a-c. An altered fourth ventricle contour, tumor-free ventricular floor and cavity [Figure 1]b, and the evidence of cystic change in the midbrain [Figure 1]c suggested brainstem-intrinsicality. There was patchy contrast enhancement of the lesion [Figure 2]. There was gross ventriculomegaly. A ventriculo-peritoneal shunt was followed by an open biopsy via a retro-mastoid suboccipital route. Intraoperatively, the cranial nerves in the cerebello-pontine angle were found to be displaced dorsolaterally by a grayish, soft and vascular lesion. There was no pial plane between the cisternal component of the lesion and the brainstem. The fourth ventricle was confirmed to be tumor-free. Histopathologic examination revealed a hypercellular tumor with predominantly rounded tumor cells. The cytoplasmic processes of the cells formed perivascular pseudorosettes [Figure 3]a. The tumor was immunopositive for glial fibrillary acidic protein [Figure 3]b and epithelial membrane antigen. The MIB-1- Ki-67 index of the tumor was 10% [Figure 3]c and there were areas of focal necrosis. A diagnosis of anaplastic ependymoma (WHO Grade III) was made. MRI of the spine ruled out cerebrospinal fluid dissemination of the disease. The patient succumbed to his disease a month after commencing adjuvant radiation and chemotherapy.
Figure 1: T2-weighted axial MRI sequences: (a) section through the lower pons showing a diffuse, hyperintense lesion merging imperceptibly with the exophytic component in the prepontine and cerebellopontine angle cisterns. A small extension into the right internal auditory canal is noted. (b) section through the mid-pontine level showing a deformed contour of the tumor-free fourth ventricle and a thin layer of normal tissue constituted by the floor of the fourth ventricle; (c) section through the midbrain showing the rostral extent of the lesion with cystic change on the right side

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Figure 2: T1-weighted, gadolinium-enhanced MRI sequences: (a) axial section showing heterogeneous contrast uptake in the hypointense lesion; (b) mid-sagittal section demonstrating the rostral-caudal extent of the lesion, a tumor-free fourth ventricle and an effaced prepontine cistern

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Figure 3: Paraffin section of the lesion showing (a) increased cellularity, brisk mitosis and ependymal canal (curved arrow) with (b) immunopositivity for GFAP and (c) high MIB-1 labeling index [(a) Hematoxylin and Eosin, × 100; (b), (d) Avidin biotin complex immunoperoxidase method, × 400]

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It is infrequent that a ventricular or foraminal connection is elusive in relation to the ependymomas that typically arise from the floor, roof, or lateral recesses of the fourth ventricle. The radial glial cell (RGC) hypothesis, that explains such aberrant extraventricular occurrences, [3] is applicable in our patient as well. RGCs have been demonstrated to occur in a mid-sagittal arrangement in the BS. [4] The tumorous cells probably radiated outwards in the substance of the BS from this midline seam and, on the eventual pial breach by virtue of their aggressive malignant potential, produced the bilaterally symmetric exophytic components.

 » References Top

1.Roncaroli F, Consales A, Fioravanti A, Cenacchi G. Supratentorial cortical ependymoma: Report of three cases. Neurosurgery 2005;57: E192.  Back to cited text no. 1
2.Niimi M, Yoshida K, Mayanagi K, Kawase T. Extensive and dense calcification in the core of a ventrally exophytic brainstem glioma. Brain Tumor Pathol 2002;19:101-3.  Back to cited text no. 2
3.Taylor MD, Poppleton H, Fuller C, Su X, Liu Y, Jensen P, et al. Radial glia cells are candidate stem cells of ependymoma. Cancer Cell 2005;8:323-35.  Back to cited text no. 3
4.Mori K, Ikeda J, Hayaishi O. Monoclonal antibody R2D5 reveals midsagittal radial glial system in postnatally developing and adult brainstem. Proc Natl Acad Sci U S A 1990;87:5489-93.  Back to cited text no. 4


  [Figure 1], [Figure 2], [Figure 3]

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