 |
|
||||
| Home | Login | |||||
| About | Editorial board | Articles
|
NSI Publications
|
Search | Instructions | Online Submission | Subscribe | Videos | Etcetera | Contact |
|
||||||||||||||||||||
|
|
|
Extramedullary astrocytoma of conus region : a short report.
Correspondence Address:
A 55 year old man presented with features of cauda equina syndrome. Magnetic resonance imaging (MRI) showed a well demarcated intradural extramedullary tumour at L2 vertebra. At surgery it was found to be well encapsulated and had no attachment to spinal cord or root. Histopathology including immunohistochemistry confirmed it to be a low grade astrocytoma.
Astrocytomas are usually intramedullary tumours. At times few of them may have an extramedullary component.[1] However, purely extramedullary astrocytomas are extremely rare. Such a tumour in an adult, confirmed on immunohistochemistry, is reported.
A 64 year old man presented with insidious onset numbness and weakness of left lower limb of one year duration which progressed to involve the right lower limb 6 months later. One month prior to admission he had to strian to pass urine. Clinically he had wasting of left thigh and calf muscles. The power in left hip flexures and knee extensors was 3/5. Ankle dorsiflexors, plantar flexors, knee flexors, hip extensors and in all the muscle groups of right lower limb was 4/5. There was hypoaesthesia in left L2 to S4 dermatomes. Left knee and ankle jerks were absent and the right sided were markedly diminished. Rest of the examination was unremarkable. Haematological and biochemical tests were normal. Plain X-ray of lumbar spine was also normal. A magnetic resonance imaging (MRI) study of lumbar spine revealed a well demarcated intradural mass at L2, lying to the left of conus. It was isointense to the conus in T1WI [Figure - 1] and isointense to CSF in T2WI. L1 to L3 laminectomy was performed. On opening the dura the tumour was found to be of greyish white in colour, well encapsulated, pushing cauda equina roots to right and left. It had no attachment to conus or dura but was attached to surrounding roots on left side through fine arachnoidal adhesions but did not have origin from any of the roots. It was soft suckable and nearly avascular. After intratumoural decompression, total removal was done. Post operative period was uneventful and he gradually improved neurologically. Histopathology revealed fibrillary astrocytes, microcystic areas and absence of mitotic activity on haematoxylin and eosin preparation [Figure - 2] and positivity to glial fibrillary acid i.e. protein on immunohistochemistry [Figure - 3]. Correspondance to : Dr. Prakash Singh, Classified Specialist Neurosurgery, Command Hospital (NC), C/O 56 APO.
The development of glial neoplasms in the leptomeninges, independently of an intramedullary gliomas has been reported.[2],[3],[4] It has been postulated that such tumours arise from glial heterotopias.[4] Wolback first drew attention to the presence of glial heterotopias in 1907.[5] Bailey was first to report extramedullary parietal glioma and suggested its possible origin from such heterotopias.2 Cushing and Eisenhardt reported first case of spinal extramedullary intradural glioma which looked like a meningioma but on histopathology was found to be astrocytomas.[3] Cooper et al reported 15 cases of extramedullary gliomas; 9 of these were intradural of which 5 were astrocytoma, two were in thoracolumbar region. Our case belongs to this subgroup. Lack of apparent attachment to the cord or roots and presence of a well formed capsule has been highlighted by Cooper et al.[4] It is though to be of pial origion. However despite apparent lack of attachment to surrounding structures these tumours are easily mistaken for a nerve sheat tumour or a meningioma at surgery. It is on histopathology that diagnosis is established. In our case, the diagnosis was clear on light microscopy and was further confirmed beyond doubt on immunohistochemistry. MRI in our case had excluded any intramedullary component. Complete encapsulation of tumour as seen during surgery also ruled out any such possibility. The need for post operative MRI was stressed by Dinakar et al[6] but in our case, there was no doubt on preoperative MRI and on surgery. Since total removal along with capsule of the tumour was done in the present case, astrocytoma was labelled 'low grade', and the patient was not given any radiotherapy.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||
