Research

Radiological evaluation of Intracranial Ependymoma

Ravi Shankar Prasad, Kulwant Singh, Vivek Sharma

• Department of Neurosurgery, Institute of Medical Sciences, Varanasi-221005, India

• Submitted:
March 1, 2013
• Accepted:
March 28, 2013
• Published:
May 27, 2013

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction

Ependymomas are infrequently seen tumours that have been defined as neoplasms arising from ependymal cells lining the ventricles and the central canal of the spinal cord.

Material and method

This is a retrospective study conducted at Department of Neurosurgery, Sir Sunderlal Hospital, Banaras Hindu University, Varanasi from August 2007 to December 2012. The diagnosis was made with CT scan and/or MRI brain and confirmed histologically. CT or MRI was also evaluated for contrast enhancement and associated hydrocephalus.

Results

Ependymomas constitutes 5.6% of total intracranial tumours. 81 patients were diagnosed as ependymoma based on CT scan or MRI but only 63 patients were histologically proved to be cases of ependymoma. CT scan showed low density tumours in fifty one cases; only one tumour was somewhat of high density. Tumour was hypo intense in T1 and hyper intense in T2 in all the 11 cases. Eighty one percent of tumours were homogenously enhancing and only 19% showed heterogeneous enhancement. Hydrocephalus was present in 63.5% patients. Calcification was seen in 25.4% patients.

Conclusion

Intracranial ependymoma constitute a significant proportion among brain tumours. CT scan and/or MRI are required for early detection and better management.

Introduction

Ependymomas are infrequently seen tumours that have been defined as neoplasms arising from ependymal cells lining the ventricles and the central canal of the spinal cord. The four most prevalent locations are supra and infratentorial, spinal and conus-cauda filum. It is the third most common infratentorial tumour of childhood. They constitute 2 to 9% of all intracranial tumours and up to 12% of pediatric brain tumours [1, 2, 3, 4, 5].

About 10% of these tumours, particularly those of higher grade, are thought to spread via the cerebrospinal fluid. As it spills out into the basal cisterns, the tumour can mingle with the lower cranial nerves [6]. Unfortunately, aggressive resection of such lesions arising in the CP angle can be associated with significant postoperative deficits [7].

CT scan and/or MRI brain is required for diagnosis, to see the extent of lesion, its ressectability and CSF spread. It is also required to see recurrence, residual tumour after surgery and planning of radiotherapy.

Material and Methods

This was a prospective study conducted at Department of Neurosurgery, Sir Sunderlal Hospital, Banaras Hindu University, Varanasi from August 2007 to December 2012. The diagnosis was made with CT scan and/or MRI brain and confirmed histologically. CT or MRI was also evaluated for contrast enhancement and associated hydrocephalus.

Results

Total number of patients of tumours was 1125 out of which 696 were supratentorial tumours and 429 were infratentorial. Out of these cases, 81 patients were diagnosed as ependymoma based on CT scan or MRI but only 63 patients were histologically proved to be cases of ependymoma. This constitutes 5.6% of total intracranial tumours. Among the remaining 18 cases, 3 turned up as subependymoma, 5 as medulloblastoma, 3 as metastasis, 4 as astrocytomas and 3 as oligodendrogliomas and all these cases were excluded from the study. We considered only 63 histologically proven cases of ependymoma.

Table 1: Location of Ependymomas (n=63)

Location	No. of cases (n=63)	Percentage
Supratentorial Parenchymal Third ventricle Lateral ventricle	14 4 2 8	22.2% 6.3% 3.2% 12.7%
Infratentorial Lateral extension Floor extension Lateral + Floor extension No extension	49 10 19 15 5	7.8% 15.9% 30.2% 23.8% 7.9%

CT scan was done in 52 cases and MRI was done in eleven cases. Forteen cases were in supratentorial region, out of which four were parenchymal, eight were in lateral ventricle and two patients had tumor in the third ventricle. Forty nine patients had ependymoma in infratentorial region. In ten patients, tumour was extending laterally to CP angles and cisterns. In nineteen cases, tumor was extending in floor of fourth ventricle. Few cases were located purely inside the fourth ventricle without any lateral extension or extension to floor (Table 1). CT scan showed low density tumours in fifty one cases; only one tumour was somewhat of high density. Tumour was hypo intense in T1 and hyper intense in T2 in all the 11 cases. Eighty one percent of tumours (51 cases) were homogenously enhancing and only 19% showed heterogeneous enhancement. Hydrocephalus was present in 63.5% patients. Calcification was seen in 25.4% patients. Cystic and hemorrhagic regions were also seen (Table 2).

Table 2: CT/MRI findings in Ependymomas (n=63)

CT/MRI findings	No. of cases (n=63)	Percentage
Calcification	16	25.4%
Cystic/Hypodense component	7	11.10%
Haemorrhage	6	9.5%
Hydrocephalus	40	63.5%

Discussion

Ependymomas are infrequently seen tumours and they arise from ependymal cells lining the ventricles and central canal of the spinal cord. It constitutes 2-9% of all intracranial tumours according to literature [1, 2, 3, 4, 5].

On CT scanning, ependymomas are usually demonstrated as low density masses, often accompanied by hydrocephalus [8]. In our study also out of 52 cases who had CT scan, 51 showed low density lesions and only 1 showed high density tumour. MRI with and without contrast is the preferred neuro imaging modality for both diagnosis and surgical planning because it provides greater soft tissue details. However, in our series we could get only 11 patients MRI done because MRI is quite costlier than CT scan. In all the 11 patients T1 weighted images were hypo intense and T2 were hyper intense. Often the tumours are heterogeneously enhancing in CT or MRI [9]. Same was with our observation also, we also had 12 tumours that were heterogeneously enhancing and 51 were enhancing homogenously we had 25% patients with calcification and 11% with cystic or hypodense areas. Literature also has documentation of areas of calcification and cystic components. Hemorrhage is reported in 10% cases [10, 11, 12, 13]. We also had 9.5% cases of hemorrhage. In 63.5% cases, ependymomas either of supratentorial or of infratentorial regions were associated with hydrocephalus.

Conclusions

Intracranial ependymoma constitute a significant proportion among brain tumours. CT scan and/or MRI brain is required for early detection. CT scan shows hypodense lesions and MRI shows hypo intense masses in T1 and hyper intense masses in T2 weighted images. Calcification, cystic areas, intratumoral hemorrhages are seen.

Conflict of Interests

The authors declare that they have no competing interests.

Authors’ Contribution

RSP: Concept and Analysis of cases study, Literature search and preparation of manuscript.
KS: Concept and design of study.
VS: Concept of study and final approval of manuscript.

Funding

None Declared

Ethical Considerations

The study was approved by Institute Review Board

Acknowledgement

None

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