Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 4, 2010, pp. 659-661

Neurology India, Vol. 58, No. 4, July-August, 2010, pp. 659-661

Case Report

Contrasting behavior of glio-ependymal cysts: A report of two cases and literature review

Umredkar Alok, Mohindra Sandeep, Gupta Rahul, Bal AmanK

Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh

Correspondence Address:Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, alokumr@yahoo.co.in

Date of Acceptance: 01-Feb-2010

Code Number: ni10174

PMID: 20739818

DOI: 10.4103/0028-3886.68702

Abstract

Keywords: Cyst, ependymal cyst, neuroepithelial cyst

Introduction

Intracranial cysts may be intracerebral or extracerebral. Arachnoid and subarachnoid cysts are among the common extracerebral cysts. These cysts may be of developmental, traumatic or inflammatory origin. The cysts, lined by epithelial, ependymal cells are described under various names: ependymal, glio-ependymal, neuroepithelial, choroidal epithelial and epithelial cysts. ^[1] We report the clinical details of two young patients with glio-ependymal cysts.

Case Reports

Case 1

A 25-year-old female presented with recurrent episodes of seizures for the past 2 years. Seizures were generalized tonic-clonic in nature and were partially controlled with antiepileptic drugs (AED). She had early morning headache for the past 1 year and developed altered sensorium four days prior to presentation, without any focal signs. Computerized tomography (CT) scan showed a well-defined non-enhancing cystic lesion in right frontal lobe. Magnetic resonance imaging (MRI) confirmed the CT findings and ruled out the presence of any associated mural nodule [Figure - 1]a-c.

She underwent right frontal craniotomy and excision of the cysts. Intraoperatively, the cysts were thin membranous, well defined, easily separable from brain parenchyma, containing clear fluid. Postoperative course was uneventful and she remains symptom-free at 1 year of follow-up. The surgical specimen revealed a thick layer of glial/connective tissue lined by a single layer of columnar epithelium. The epithelium was diffusely positive for S-100 protein and glial fibrillary acidic protein (GFAP), confirming glio-ependymal cyst [Figure - 1]d.

Case 2

A 25-year-old male presented in a decerebrating state in the neuro-surgical emergency. The MRI scans [Figure - 2]a-c brought by the patient done showed a large cystic lesion in left temporal lobe. She had an emergency twist drill tap of the cyst, which showed clear cerebrospinal fluid (CSF) like fluid. After 12 hours of the life-saving cyst tap, patient had improvement in his conscious state, but remained in altered sensorium. Left temporal craniotomy and mid-temporal gyrus resection was performed so as to lay open the cyst. The cyst wall was biopsied which showed a layer of glial tissue lined by columnar epithelium. Definitive pathologic diagnosis was glio-ependymal cyst. Postoperatively, the patient continued to improve and remains asymptomatic at 18 months of follow-up and the imaging showed no residual or recurrence lesion [Figure - 2]d.

Discussion

Glio-ependymal cysts, also known as neuroepithelial cysts, are thought to arise from ectopic rests of primitive neuroglial tissue, and hence, can arise anywhere in the neuraxis ^[2],[3] [Table - 1]. Generally, these cysts present in the second or third decade, ^[4] but have been reported at all ages and even in intrauterine period. ^[3],[5],[6] Clinical presentations include seizures, ^[7],[8] symptoms due to mass effect ^[3],[7],[8] and some are incidental. ^{[9],[10],[11]}

The cyst wall is composed of an inner glial layer with a luminal ependymal lining and an outer fibrous layer with no external lining cells. The lining ependymal cells have vacuoles, bleb-like protrusion, normal and abnormal cilia, and microvilli, the latter are sometimes distended and detached into the lumen. These cysts have neither pinocytic vesicles nor a basement membrane. The glial layer contains astrocytes, glial bundle and ependymal cells. This cyst appears to have originated from a leptomeningeal neuroglial heterotopia and may represent a continued proliferative growth rather than degenerative change of the heterotopias. ^[9]

On imaging, glio-ependymal cysts appear as nonenhancing CSF containing unilocular thin-walled cysts, found both in intra-axial and extra-axial locations. They are difficult to be differentiated from arachnoid cyst, enterogenous cyst, ependymal cyst, dermoid cyst, encephalocele and congenital dysplasia of sphenoid wing in neurofibromatosis 1. ^[3] MR proton spectroscopy remains an inconclusive diagnostic tool till the present time; however, resonance of N-acetyl group of the compound may be a subtle indicator of glial tissue within ependymal lining. ^[12]

Associated congenital brain malformations have been documented in the antenatal period, ^[6],[13] adolescents and elderly. Clinical presentation of raised intracranial pressure may be attributed to the cysts per se while associated developmental anomalies may account for seizures.

Treatment may not be warranted in incidentally detected glio-ependymal cysts, but treatment may be required for symptomatic cysts. Surgical management may be considered superior to AEDs. The proliferative nature of these lesions justifies their surgical removal. ^[13] Surgical intervention may include cysto-peritoneal shunt, ^[3] cysto-arachnoid shunt, ^[7] partial excision, ^[13] marsupilization, ^[1] fenestration or total excision. ^[4],[8],[14] Surgical outcome remains satisfactory without recurrence or repeated surgeries after complete removal.

References

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