Schwannomas represent 7% - 10% of all primary intracranial tumors. GSs are rare and only 39 cases have been reported. GSs present in the third to fifth decades of life, with a slight female predisposition. Kaye et al classified jugular foramen schwannomas into the following three types:
Type A: a primary intracranial tumour in the cerebellopontine angle with minimum enlargement of jugular foramen and with a small extension into the bone (most common type);
Type B: a tumor mainly invading the bone (jugular foramen) with or without an intradurakl component;
Type C: a tumour that is primarly extracranial in location with a minor extension to the bone or into the posterior cranial fossa;
Type D (added by Pellet et al): saddlebag-shaped tumour with intracranial and extracranial components.
The symptoms are non-specific, and include hearing loss, tinnitus, vertigo, gait ataxia, headache, nystagmus, hoarseness of voice, palate-pharyngeal and facial hypoaesthesia, and rarely, papilloedema and dysphagia. Differential diagnosis: vestibular nerve schwannoma. MR imaging will give some clues towards the nerve of origin but the diagnosis is usually accomplished only at surgery. Total removal should be the goal of the operation; however, partial resection could be an option in the presence of large tumors with dense adhesions to the other cranial nerves and brainstem.
Type A: a primary intracranial tumour in the cerebellopontine angle with minimum enlargement of jugular foramen and with a small extension into the bone (most common type);
Type B: a tumor mainly invading the bone (jugular foramen) with or without an intradurakl component;
Type C: a tumour that is primarly extracranial in location with a minor extension to the bone or into the posterior cranial fossa;
Type D (added by Pellet et al): saddlebag-shaped tumour with intracranial and extracranial components.
The symptoms are non-specific, and include hearing loss, tinnitus, vertigo, gait ataxia, headache, nystagmus, hoarseness of voice, palate-pharyngeal and facial hypoaesthesia, and rarely, papilloedema and dysphagia. Differential diagnosis: vestibular nerve schwannoma. MR imaging will give some clues towards the nerve of origin but the diagnosis is usually accomplished only at surgery. Total removal should be the goal of the operation; however, partial resection could be an option in the presence of large tumors with dense adhesions to the other cranial nerves and brainstem.
References
- Samii M, Babu RP, Tatagiba M, Sepehrnia A. Surgical Treatment of jugular foramen schwannomas. J Neurosurg 1995; 82:924-32
- Gupta V, Kumar S, Singh AK, Tatke M. Glossopharyngeal schwannoma: a case report and review of literature. Neurol India 2002; 50:190-3
- Samii M, Tatagiba M. Tumours of the jugular foramen. Neurosurg Q 1996; 6:176-93
- Agrawal A, Pandit L, Bhandary S, Makannavar JH, Srikrishna U. Glossopharyngeal schwannoma: diagnostic and therapeutic aspects. Singapore Med J 2007; 48(7): e 181-5
- Kaye AH, Hahn JF, Kinney SE, Hardy RW, Bay JW. Jugular foramen schwannomas. J Neurosurg 1984; 60:1045-53
- Pellet W, Cannoni M, Pech A. The widened transcochlear approach to jugular foramen tumors. J Neurosurg 1988; 69:887-94.
