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Background: Schwannomas are solitary neurogenic tumors originating from the myelin sheath of peripheral nerves. Extracranial hypoglossal schwannomas comprise <5% of all head and neck schwannomas and can mimic submandibular salivary gland tumors., Case Report: We report the diagnostic imaging, surgical treatment, and histopathological findings of a rare case of extracranial schwannoma of the hypoglossal nerve in a 73-year-old female, presented with an asymptomatic swelling in the left submandibular region that had been persisted for approximately three years., Conclusion: Accurate diagnosis of this rare clinical entity requires comprehensive diagnostics. The optimal therapeutic strategy is nerve-sparing surgical excision, although it can be challenging., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Schwannomas or neurilemmomas are well-encapsulated, benign, solitary, and slow-growing tumors that originate from Schwann cells of the nerve sheath. Extracranial schwannoma is reported to have a relatively high incidence in the tongue while an extremely low incidence in the floor of mouth. In the current study, we presented the first case series of hypoglossal nerve-derived schwannoma in the floor of mouth in Asia., Methods: A retrospective study of 9 surgical cases of hypoglossal nerve-derived schwannoma in the floor of mouth was performed. The patient and tumor characteristics were evaluated by physical, radiological and pathological examination. Details of operation and complications were also recorded., Results: Hypoglossal nerve-derived schwannoma in the floor of mouth showed a well-defined boundary with a firm texture, smooth surface and good mobility on palpation. The median maximum diameter of the tumors was 4.3 cm (range 2.8-7.0 cm). The median operative time and bleeding volumes were 89.4 min (range 47-180 min) and 99.2 mL (range 15-200 mL), respectively. All cases received complete surgical excision., Conclusion: In this study, we presented the diagnosis and management of hypoglossal nerve-derived schwannoma in the floor of mouth for the first time in Asia. The study provided us with a recommendation for consideration of the diagnosis of hypoglossal schwannoma when a patient presents with a mass in the floor of mouth., (© 2022. The Author(s).)

A 4 yr old male Maltese dog presented with a 1 wk history of intermittent neck pain and progressive difficulty walking. Neurologic evaluation was consistent with a left-sided brainstem lesion. On oral examination, left lingual hemiatrophy was evident suggesting hypoglossal nerve involvement. A dumbbell-shaped extra-axial mass in the left side of the caudal fossa extending extracranially through the hypoglossal canal was detected by MRI. At postmortem histologic examination, the hypoglossal nerve was diffusely infiltrated by fusiform neoplastic cells arranged in Antoni A and Antoni B patterns. This is the first description of a malignant nerve sheath tumor selectively involving the hypoglossal nerve in a dog., (© 2022 by American Animal Hospital Association.)

A 40-year-old woman presented with insidious onset, gradually progressive dysarthria and inability to manoeuvre bolus of food in her mouth while eating. The duration of her symptoms was 3 months. On evaluation, the left half of her tongue was wasted. The tongue deviated to the left on protrusion. There were no clinical features suggestive of involvement of the ipsilateral 9th, 10th or 11th cranial nerves. MRI of the brain showed a large, fusiform lesion in the left hypoglossal canal, extending into the jugular canal. The lesion was surgically excised and found to be a schwannoma., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Hypoglossal nerve schwannoma, especially when inside the extracranial region, is extremely rare. This report describes a new endoscopic transoral approach for the removal of extracranial hypoglossal schwannoma., Patients and Methods: Three patients (1 male and 2 females, aged 58-63 years) with extracranial hypoglossal schwannoma in the paroccipital condyle and the jugular foramen were treated solely by an endoscopic transoral approach. All patients presented signs of hypoglossal nerve paresis with hemiatrophy of the tongue. In addition, one of them had glossopharyngeal nerve paresis, and vagus nerve paresis was found in another patient., Results: In all patients, tumors underwent successful radical intracapsular removal by the endoscopic transoral approach, as confirmed by the postoperative examinations and MRI. No complications occurred during or after surgery, except that 1 patient had swallowing difficulties and a temporary right vagus palsy during the first day after surgery. All patients were followed up for 6 months, and the lack of any recurrence has been confirmed. Muscle bulk, motor and swallowing functions, and the vagus palsy improved in all patients., Conclusion: The endoscopic transoral approach is a safe and useful surgical technique for the removal of intracapsular tumors, including extracranial hypoglossal schwannomas, which involves minimal invasion., (Copyright © 2011 S. Karger AG, Basel.)

Objective: Hypoglossal nerve schwannomas are rare tumours that usually cause ipsilateral hypoglossal palsy. This report describes such lesions in two patients and suggests nerve grafting as part of the treatment regimen., Method: Two patients with intra- and extra-dural hypoglossal schwannomas respectively were treated by direct surgery via a postero-lateral approach to the posterior fossa, hypoglossal canal and carotid sheath. Following tumour removal, sural nerve grafting was used to reconstruct the nerves. Unexpectedly, muscle bulk and motor function returned within 6 months in both patients., Conclusion: Nerve grafting was highly successful in achieving functional recovery following surgery for hypoglossal nerve schwannomas.

There have been only 26 cases of hypoglossal schwannomas reported to originate intradurally and extend extradurally into the hypoglossal canal. This 31-year-old mother of two children presented with a 5-day history of progressive headache, nausea, vomiting and vertigo. Her neurological exam was significant for nystagmus and left tongue deviation with marked atrophy. An initial head CT revealed extensive left hypoglossal canal erosion with 4th ventricle compression. T1-weighted MR images with contrast revealed a 4x3 cm left cerebellopontine angle non-homogeneously enhancing mass with an intracranial cystic component and prominent extension into the eroded hypoglossal canal. A left lateral suboccipital craniotomy was performed for subtotal microsurgical resection of the intradural posterior fossa mass. A schwannoma was diagnosed after resection and gamma knife surgery (GKS) was performed three months later for the extradural residual tumor without further deficits. This is a rare report of a hypoglossal schwannoma in a young patient who was treated with a multimodality approach in order to minimize risks. A review of the literature and discussion of the respective benefits of microsurgery versus GKS and long-term follow-up issues are presented.

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.

Primary lesions of the hypoglossal canal, such as hypoglossal schwannomas, are rare. No consensus exists with regard to the surgical approach of choice for treatment of these lesions. Usually, lateral transcondylar approaches have been used. The authors describe the surgical anatomy of the midline subtonsillar approach to the hypoglossal canal. This approach includes a midline suboccipital craniotomy, dorsal opening of the foramen magnum and elevation of ipsilateral cerebellar tonsil to expose the hypoglossal nerve and its canal. The midline subtonsillar approach permits a straight primary intradural view to the hypoglossal canal. There is no necessity of condylar resections. The surgical anatomy of the subtonsillar approach is described and illustrated by an example of a case.

Background: Neurilemmoma are benign tumors of the nerve-sheath, also known as schwannoma. Beside intracranial manifestation, neurilemmoma are found at other peripheral nerves of the head and neck., Case Report: We present three cases of patients with seldom manifestation of neurilemmoma of the supraglottis, the retropharyngeal space and a neurilemmoma of the hypoglossal nerve. The histological examination showed two types of Antoni-A-neurilemmoma, whereas one tumor was found with mixed type A and B-neurilemmoma., Conclusion: Although extracranial neurilemmoma of retropharygeal space, neck or supraglottic larynx are rare tumors, neurilemmoma should be involved in differential diagnosis of tumors in these areas. The therapy of choice consists of complete surgical removal and histological examination.

Background: Usefulness of transcervical approach to hypoglossal schwannoma with paraspinal extension is described herein., Case Description: A 54-year-old woman presented with gradually worsening left hypoglossal nerve palsy. The findings were of a tumor lying in the left hypoglossal canal and paraspinal region and were consistent with hypoglossal schwannoma. Subtotal intracapsular removal of the tumor was performed via transcervical approach. The symptoms improved, and no additional symptoms were noted., Conclusion: The transcervical approach and intracapsular removal of the tumor under electrophysiological monitoring provided for successful minimally invasive surgery in this case of hypoglossal schwannoma.

Focal or microscopic hemorrhage in a neurinoma is common, but tumor origin from the hypoglossal nerve and extensive symptomatic intratumoral hemorrhage are both rare. A 59-year-old male presented with severe neck pain, nausea and vomiting of 1-day duration, accompanied by right hypoglossal nerve palsy. Neuroimaging disclosed a tumor located in the right cerebellomedullary fissure and containing a hematoma. The right hypoglossal canal was slightly dilated. The intracranial tumor was resected via a suboccipital approach. Histological examination demonstrated spindle-shaped tumor cells with nuclear palisading and also relative hypervascularity with hyaline degeneration of the vessels. Extensive hemorrhage was present, as was necrosis. Thickening and hyalinization of arterial walls, a common occurrence in neurinomas, may have contributed to symptomatic intratumoral hemorrhage., (Copyright 2002 Published by Elsevier Science Ltd.)

Hypoglossal schwannoma is an uncommon cause of 12th nerve palsy. We here report a pathologically proven case of left 12th nerve schwannoma in a 56-year-old woman who presented with progressive left tongue hemiatrophy and in whom cranial MRI disclosed a mass near the foramen jugular. Surgery showed a mass involving the hypoglossal nerve and the pathological examination was diagnostic of schwannoma.

A rare case of cellular schwannoma of the hypoglossal nerve, with intraspinal extension, presenting without any recognisable impairment of the function of the hypoglossal nerve is presented.

The authors report an exceptional case report of tumor like evolution of a completely thrombosed aneurysm of the right vertebral artery suggestive of neurinoma of the XII nerve. We describe CT, MRI, MR-angiography. The diagnosis has been established by pathologic study after surgical extraction. Our case demonstrate the possibility of growth of totally thrombosed aneurysms and we discuss various mechanisms.

The case of a 43-year-old man with a right skull base hypoglossal neurilemmoma excised via the extended posterolateral approach is presented. There is only one previous case of hypoglossal neurilemmoma in the literature. The surgical technique described is a new approach to the posterior skull base involving a suboccipital craniectomy, mastoidectomy and the removal of the lateral process of the atlas. It provides an inferior approach to the jugular foramen and hypoglossal canal that allows the lower cranial nerves to be identified as they exit from their skull base foramina. In the discussion we compare this technique to other surgical approaches previously described for access to the region of the jugular foramen.

Neurilemmomas of the peripheral segment of the hypoglossal nerve are extremely uncommon neoplasms. A rare case of hypoglossal neurilemmoma located in the sublingual space is reported and the differential diagnosis of sublingual mass lesions is discussed.

A case of dumbbell-shaped hypoglossal neurinoma with intra- and extracranial extension is reported. The tumour was surgically completely removed in a one-stage operation via a dorsolateral sub-occipital transcondylar approach. Clinical presentation and the role of high-resolution CT-scan, MRI and angio-MRI in diagnosis and surgical planning are discussed. We include a review of the literature concerning these rare tumours of the foramen magnum region.

A 46-year-old female presented with an intracranial hypoglossal neurinoma manifesting only as spasticity in the lower extremities without hypoglossal nerve paresis. Magnetic resonance imaging greatly aided in the early detection of the tumor with this atypical presentation. Unilateral suboccipital craniotomy with resection of the occipital condyle allowed us to approach the tumor in front of the medulla from an inferolateral direction and to remove it successfully. We emphasize the need to pack dead space with fatty tissue to prevent cerebrospinal fluid leakage.

Schwannomas account for 8.5% of all intracranial tumours; more than 90% arise from the 8th cranial nerve. Only 42 cases of schwannoma of the hypoglossal nerve have been reported. A 59 year-old woman developed right hemiatrophy of the tongue, clearly demonstrated on MRI, as was a small hypoglossal schwannoma. High signal was seen in the atrophic side of the tongue on both T1- and T2-weighted images, as described in the literature.

The unusual case of a ventral brain stem schwannoma located at the entry zone of the hypoglossal nerve in a 49-year-old woman is reported. The diagnosis of a schwannoma was confirmed histologically after partial tumor resection via the dorsolateral, suboccipital, transcondylar approach. Hypotheses for the pathogenesis of intramedullary schwannomas are discussed.

Parapharyngeal neurilemmomas are uncommon benign tumours. Two patients are reported with one tumour arising from the vagus and the other from the hypoglossal nerve. Access to the vagal tumour was accomplished with the aid of an osteotomy at the angle of the mandible. Theoretically these lesions can be enucleated with preservation of the nerve or resected and repaired with a nerve graft. However, these alternative procedures were impractical in both these patients and the explanations for this are discussed.

Although neurilemmomas are uncommon cervical neoplasms, they account for a significant percentage of parapharyngeal space tumors. These neoplasms may originate from any nerve traversing this space, but the vast majority arise from the vagus nerve and sympathetic chain. Satisfactory treatment of neurilemmomas consists of total excision which is best accomplished via an external approach. Immediate nerve grafting is advocated when a segment of cranial nerve must be sacrificed in order to achieve complete tumor removal. A case of a parapharyngeal neurilemmoma arising from the hypoglossal which required treatment in this manner is presented. Electromyographic studies performed 15 months postoperatively demonstrate reinervation of the lingual musculature via the nerve graft.