Hypoglossal neurinoma extending intra- and extracranially: Case report

Intradural Microsurgery and Extradural Gamma Knife Surgery for Hypoglossal Schwannoma: Case Report and Review of the Literature

“…Most schwannomas of the hypoglossal nerve are intracranial [24] , originating at the transition zone between Schwann cells and oligodendroglia, however, hypoglossal schwannomas tend to grow both intracranially compressing structures near the cerebellopontine angle and extracranially expanding into bony canals (auditory or hypoglossal) [25] . To date, less than 100 cases of schwannomas of the hypoglossal nerve have been reported [5,13,20,26] , however, there have been only 27 cases, including the present one, that have been noted to be intra-and extradural in location, the so-called dumbbell-shaped, transcranial, or transitional hypoglossal schwannomas. Although over 90 % of intracranial schwannomas are vestibular schwannomas [19,27] , schwannomas of other cranial nerves are very rare with approximately 40 % of these occurring in the trigeminal nerve, 23 % in the facial nerve, and 20 % in the lower cranial nerves [28,29] .…”

“…Our patient had no complaints related to tongue dysfunction but presented with generalized headaches and a midline cerebellar syndrome and evidence of a 12 th nerve palsy on neurological exam only. Similarily, the predominant symptoms in the review of cases included occipital headache (59 % ) which may be due to tumor expansion and compression of the cervical nerves, followed by vertigo and balance disturbances (33 % ) and nausea and vomiting (26 % ) which has been suggested to be related to a circulation disturbance of the posterior inferior cerebellar artery (PICA) [20] , as well as cerebellar or vestibular involvement. Other signifi cant neurological exam signs included lower cranial nerve palsies (63 % ), cerebellar signs (48 % ), and long-tract signs such as sensory (30 % ) and motor (18 % ) disturbances due to compression by the tumor ( ᭹ ᭤ Table 1 ).…”

Cervical Vestibular Evoked Myogenic Potential in Hypoglossal Nerve Schwannoma: A Case Report

“…Thus, VCR pathway dysfunction may be implicated in our patient. A mass lesion of CNXII can compromise CNXI (Sato et al, 1996;Hoshi et al, 2000;Awobuluyi, 2013) because CNXII lies close to CNXI in the cisternal space and at the base of the skull. Within the cranium, CNXI travels in the cerebellomedullary cistern, and CNXII travels in the premedullary cistern.…”

“…Schwannoma of CNXII is rare, constituting only 5% of all nonvestibular intracranial schwannomas (Boban et al, 2007;Osborn, 2013). CNXII schwannomas can compromise the spinal accessory and other lower cranial nerves (Sato et al, 1996;Hoshi et al, 2000;Awobuluyi, 2013).…”

Glossopharyngeal schwannoma of the suprahyoid carotid space: Case report and discussion of the relationship to the carotid artery

“…The majority of glossopharyngeal schwannomas reported in the literature arise from the intracranial component, usually in the lower cerebellopontine angle 1–4. Moreover, most of the very few reported extracranial lesions were lesions that started intracranially and developed secondarily an extracranial extension 14, 15. Extracranial schwannomas of the glossopharyngeal nerve are extremely rare and may theoretically occur anywhere along the course of the nerve within the carotid sheath.…”