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| Year : 2000 | Volume
: 48
| Issue : 1 | Page : 94-5 |
Ectopic meningioma : a case report.
Marthandapillai A, Alappat JP
How to cite this article:
Marthandapillai A, Alappat J P. Ectopic meningioma : a case report. Neurol India 2000;48:94 |
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 fossa meningioma.[1] 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 meningothelial meningioma.
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 excision is complete.
| 1. | Suzuki H, Gilbert EF, Zimmerman B: Primary extracranial meningioma. Arch Pathol 1967; 84: 202.  |
| 2. | Wolff M, Ramkow RM: Meningioma of the parotid gland and insight into the pathogenesis of extracranial meningioma: Hum Pathol 1971; 2: 453-459. |
| 3. | Zachariae L: A case of extracranial primary meningioma. Acta Pathologica 1952; 31: 37-60. |
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