Intracranial Hypoglossal Neurinoma without Preoperative Hypoglossal Nerve Paresis —Case Report—

Kobayashi, Satoshi; Otsuka, Akiyoshi; Tsunoda, Tadao; Inoué, Hiroshi

doi:10.2176/nmc.36.384

Cited by 17 publications

(2 citation statements)

References 3 publications

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“…In these instances, the neoplasm arose from the intracranial rootlets of the XII nerve. 11 Our patient presented without XII nerve deficit, and the tumor originated from the trunk. The tumor extended intracranially away from the hypoglossal nerve itself with only a small portion located in the canal.…”

Section: Discussionmentioning

confidence: 71%

Large Cystic Hypoglossal Schwannoma with Fluid-Fluid Level: A Case Report

Hong

Wang

et al. 2010

Skull Base

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Hypoglossal schwannomas are rare skull base tumors. Furthermore, cystic hypoglossal schwannomas are extremely uncommon. We report the first case of a large cystic hypoglossal schwannoma with a fluid-fluid level. A 36-year-old woman presented with increased intracranial pressure and cerebellar signs without hypoglossal nerve palsy. Magnetic resonance imaging showed a predominantly cystic mass with a fluid-fluid level in the foramen magnum region extending into the hypoglossal canal. The intracranial tumor was largely removed via a midline suboccipital subtonsillar approach, leaving only a tiny residue in the hypoglossal canal. Histology confirmed a schwannoma with relative hypervascularity. Twenty months later, the tumor recurred and presented as a multicystic dumbbell-shaped lesion, extending intra-and extracranially through the enlarged hypoglossal canal. A complete resection of the intracranial and intracanalicular parts of the tumor was achieved with a small extracranial remnant treated by radiosurgery. Histology revealed a focal increased K i 67 proliferative index. In this report, we discuss the possible reasons for the absence of hypoglossal nerve palsy and the potential mechanism of the formation of the fluid-fluid level, and we consider the treatment of this lesion.KEYWORDS: Hypoglossal schwannoma, cystic, fluid-fluid level, schwannoma Schwannomas are benign, slow-growing neoplasms of the myelin-producing Schwann cells in the peripheral sensorimotor nervous system. In more than 90% of cases, these present as vestibular schwannomas. 1Schwannomas that arise from the hypoglossal nerve, a pure motor nerve, are very rare, accounting for only 5% of all nonacoustic intracranial schwannomas. 2 To date, around 100 cases of hypoglossal schwannoma have been reported in the English literature. Hypoglossal schwannoma usually originates intracranially but can also extend extracranially through the hypoglossal canal in a so-called ''dumbbell'' fashion or can arise purely from the extracranial portion of the XII nerve. According to Kaye et al's 4 classification of the jugular foramen neurinomas, the hypoglossal schwannomas documented in the literature are divided into three types: type A, intracranial in 31.5%; type B, dumbbellshaped or extra-and intracranial in 50%; type C, extracranial in 18.5%. 5Schwannomas are frequently solid masses, and cystic patterns are uncommon. A fluid-fluid level has been observed in a few intracranial cystic schwannomas on magnetic resonance image (MRI), such as schwannomas that originate from the V, VIII, and IX nerves. 6-8Here we describe a unique case of a monocystic hypoglossal schwannoma with fluid-fluid level. To our

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Section: Discussionmentioning

confidence: 71%

Large Cystic Hypoglossal Schwannoma with Fluid-Fluid Level: A Case Report

Hong

Wang

et al. 2010

Skull Base

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“…Therefore, our patient did not present with hypoglossal nerve dysfunction preoperatively. Although a few previous reports have described intracranial hypoglossal neurinoma without preoperative hypoglossal nerve palsy [5,9] , none of the cases presented an intact trunk of the 12th cranial nerve. Thus, this is the fi rst report to clearly show the preserved rostral trunk of the 12th cranial nerve as well as the caudal trunk where the tumor originated in a patient with intracranial hypoglossal neurinoma.…”

Section: Discussionmentioning

confidence: 77%

A Case of Intracranial Hypoglossal Neurinoma Without Hypoglossal Nerve Palsy: Operative View of the Preserved Rostral Trunk

Kikkawa¹,

Shono²,

Mizoguchi³

et al. 2007

Minim Invasive Neurosurg

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Hypoglossal neurinomas usually manifest with hemiatrophy and weakness of the tongue. A rare case of intracranial hypoglossal neurinoma without preoperative hypoglossal nerve dysfunction and its operative view are presented. A 36-year-old female who presented with headaches and vertigo was admitted to our hospital. The neurological examination revealed bilateral papilledema and mild truncal ataxia, although weakness and atrophy of the tongue were not observed. Magnetic resonance and computed tomography images demonstrated a large foramen magnum tumor without enlargement of the hypoglossal canal. Total removal of the tumor was performed via a lateral suboccipital craniotomy and C1 partial laminectomy. During the operation, two trunks were observed for the hypoglossal nerve at the entrance of the hypoglossal canal. The tumor arose from the caudal trunk, while the intact rostral trunk entered the hypoglossal canal normally. The tumor only developed intracranially, and since the rostral trunk of the hypoglossal nerve was intact, the patient did not present with hypoglossal nerve palsy preoperatively.

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