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Unformatted text preview: [Downloaded free from http://www.neurologyindia.com on Tuesday, December 01, 2009] LETTERS TO EDITOR
Ectopic Meningioma : A Case Report
Primary extracranial and extraspinal meningiomas are
rare. A case of primary meningioma of the lateral
pterygoid plate in a young woman is described.
Suzuki et al described the first case of pterygopalatine
A twenty year old girl was admitted with complaints
of bulge in the left temporal region of two years
duration. On examination there was fullness of the
left temporal fossa. Her neurological and ENT
examination was normal. CT scan of the head showed
a mass in the pterygopalatine fossa extending into the
left subtemporal region. She underwent a craniofacial
excision of the tumour. A well encapsulated firm mass
3 cms x 2 cms was excised after severing the
attachment to the lateral pterygoid plate.
Histopathological examination showed evidence of
It is generally agreed that meningiomas originate from
meningiocytes (arachnoid cells or meningothelial
cells) capping the arachnoid villi or pachionian
granulations. However, clusters of arachnoidal cells
have been found at the exits of the cranial and spinal
nerves from the skull and vertebrae, and in the sheath
of cranial nerves both inside and outside the cranial
cavity. The presence of such cells has also been
suggested in the cranial periosteum. Heterotopic brain
and meningeal tissue is known to occur occasionally
in the midline of head, neck and trunk due to
displacement of such tissue during the fusion of skull
and spine in the embryonic state. The largest group of
ectopic meningiomas had occurred within the orbit,
the origin probably being the arachnoid cells in the
sheath of the optic nerve followed by primary
meningiomas of the nasal cavity and paranasal
sinuses. The other ectopic sites include parotid gland,
bifurcation of carotid artery, little finger of right hand,
brachial plexus, scalp, face and paravertebral region.
In the present case, the diagnosis of primary ectopic
meningioma was based on the fact that there was no
clinical and radiological evidence of an intracranial
lesion. The position of the tumour at surgery
confirmed that it had arisen from the lateral pterygoid
plate with extension into the temporal fossa. Most of
the primary ectopic meningiomas are of
meningothelial or psammomatous origin. It is of
interest to note that no angioblastic meningioma has
yet been described. It is possible that these types of
meningioma may have been regarded as
haemangiopericytoma or other vascular lesions.2,3
The prognosis of ectopic meningioma is good if the Neurology India, 48, March 2000 Fig. 1 : CT scan of the head showing a mass in the
pterygopalatine fossa. excision is complete.
A. Marthandapillai, J.P. Alappat
Department of Neurosurgery, Medical College,
Trivandrum, Kerala - 695 011. References
3. Suzuki H, Gilbert EF, Zimmerman B : Primary extracranial
meningioma. Arch Pathol 1967; 84 : 202.
Wolff M, Ramkow RM : Meningioma of the parotid gland
and insight into the pathogenesis of extracranial
meningioma : Hum Pathol 1971; 2 : 453-459.
Zachariae L : A case of extracranial primary meningioma.
Acta Pathologica 1952; 31 : 37-60. 88 ...
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This note was uploaded on 12/11/2009 for the course UNT 123456 taught by Professor 123456 during the Spring '09 term at University of North Texas Health Science Center.
- Spring '09