Nerve Schwannoma Research Articles

Interdural extra-arachnoidal resection of fifth nerve schwannomas with tailored petrous drilling: Eliminating the blind spot

Background and objectives Around 20-40% of trigeminal schwannomas (TS) are dumbbell shaped, spanning the middle and posterior cranial fossa The petrous apex is often truncated in these patients, aiding surgical resection of both compartments through the middle fossa approach. However, a less eroded petrous creates a blind spot, making total resection difficult. This study describes the feasibility of an approach combining expanded Meckel cave access with tailored petrous bone drilling to optimize tumor visualization and resection. Methods Eleven patients with dumbbell TS and minimal petrous apex erosion underwent the described surgery. Surgical steps included temporo-orbito-zygomatic craniotomy, middle fossa floor drilling, navigation aided (tailored) extradural petrous bone drilling and extra-arachnoidal tumor excision. Extent of resection and postoperative outcomes were recorded. Results Patients presented with trigeminal nerve dysfunction (n = 9; sensory −9 and motor − 5), headache(8/11), ataxia (7/11) and pseudobulbar palsy (3/11). Complete tumor resection was achieved in all patients. Postoperatively, 8 out of 9 patients had transient increase in facial hypoesthesia with conjunctival injection in 3. It improved within 3-6 months, except in four cases wherein mild hypoesthesia persisted. Motor symptoms improved in 2 of 5 patients. Two developed transient 6th nerve paresis, that resolved in 2 months. Cerebellar and brainstem pressure symptoms resolved in all. No patients developed new onset permanent neurological deficit. Two patients reported mild post-craniotomy masticatory difficulty. Conclusions The additional tailored petrous bony drilling enhances the surgeon’s view, allowing a higher chance of total resection with no major operative morbidity.

Schwannoma-like Breast Metastasis in the Meckel Cave: Case Report

AbstractTumors of the Meckel cave are very rare lesions, especially if they are malignant. We report the case of a patient who presented with a breast metastasis in the Meckel cave and a clinical presentation similar to that of a fifth nerve schwannoma.

Long-Term Outcomes of Non-Vestibular Cranial Nerve Schwannomas Treated with Fractionated Stereotactic Radiotherapy and Stereotactic Radiosurgery

Non-vestibular cranial nerve schwannomas (NVCNS) are rare tumors that account for approximately 10% of cranial nerve schwannomas. They are commonly treated with radiation therapy (XRT) due to their location often precluding safe resection. We examined the long-term outcomes of NVCNS treated with XRT as primary management and for post-operative salvage. We conducted a retrospective review of patients with NVCNS treated with fractionated stereotactic radiation therapy (FSRT) or Gamma Knife Stereotactic Radiosurgery (GK-SRS) from 1996 to 2018 at our institution. We examined patient demographics, cranial nerve (CN) involvement, CN function pre-/post-XRT, treatment volume (TV), toxicity, surgery pre-XRT, and local control. Kaplan-Meier analysis was performed for evaluation of local control. We identified 66 patients (38 female, 28 male) with NVCNS, a portion of whom had tumors involving more than one cranial nerve. Forty-six (69.7%) were treated with FSRT (median dose 50.4 Gy in 1.8 Gy/fraction; range 45-54 Gy), and 20 (30.3%) with GK-SRS (median dose 12 Gy; range 12-15 Gy). Median follow-up time was 92.5 months (5-306). Median Karnofsky Performance Status was 90 (70-100). Median age at start of XRT was 45 years old (15-92). Prior to XRT, 34.8% (23) of patients had surgical resection, with median time from surgery to XRT of 4.25 months (0.5-130 months). Median treatment volume was 4.72 cc (0.26-29). The cranial nerve most commonly involved was CN V (48.4%), followed by CN X (15.2%), CN VII (13.6%), CN VI (6.1%), CN XII (6.1%), CN III (6.1%), and CN IX (3%). Twenty-nine (43.9%) patients experienced grade 1 acute toxicity during treatment. Six (9%) patients experienced grade 1 chronic toxicity. No grade 2 or higher acute or chronic toxicity was observed. No significant difference in rates of acute or chronic toxicity was observed between patients treated with GK-SRS vs. FSRT. Post-XRT, 37 patients (56.1%) had improvement in CN function/symptom, 24 patients (36.3%) had stable function/symptoms, and 5 patients (7.6%) had worsening function/symptoms. Local control at one and five years was 100%. In-field recurrence was observed in one patient (1.5%), at 9 years post-XRT. For salvage this patient was treated with a second course of FSRT to the recurrent tumor. Our large institutional series with long term follow up showed excellent local control of NVCNS treated with FSRT or GK-SRS both for primary management and post-operative salvage. Treatment is well tolerated, with high rates of preservation or improvement of CN function, and minimal acute and chronic toxicity.

Analysis of Nonvestibular Cranial Nerve Schwannomas

Background and Aim: Cranial nerve (CN) schwannomas other than the eighth nerve schwannoma are called nonvestibular cranial nerve schwannomas (NVCNS). This study aims to analyze the clinical profile, distribution, and surgical outcome of the NVCNS. Methods and Materials/Patients: This is a retrospective study analyzing the NVCNS conducted between January 2007 and December 2021. VIIIth cranial nerve schwannomas and conservatively managed NVCNS were excluded from the study. Results: This study included 25 patients with NVCNS. Ten patients (40%) had trigeminal schwannomas, 3(12%) facial nerve schwannomas, 9 (36%) lower cranial nerve (LCN) schwannomas, 1 (4%) vagal schwannoma in neck and 2(8%) hypoglossal schwannomas. Eight patients (32%) were male and 17(68%) were female. The age of the patients ranges from 13 to 62 years (mean 39 years +/- 14 SD). Findings of cerebellar involvement, VIIIth CN involvement, and headache are the most common clinical features. The posterior cranial fossa is the most common location of the tumors. Thirteen patients (52%) underwent gross total resection (GTR), 7(28%) underwent neartotal resection (NTR) and 5(20%) underwent subtotal resection (STR). All the patients improved in the postoperative period. Facial nerve palsy is the most common cranial nerve palsy occurring in the postoperative period. Conclusion: Trigeminal and lower cranial nerve (LCN) schwannomas are the most common NVCNS. The retrosigmoid suboccipital approach is the most commonly used surgical approach for tumors located in the posterior cranial fossa. Since NVCNS are benign lesions, postoperative clinical improvement along with decreased complications should be the goal of the surgery. Hence, gross total resection is the most commonly achieved extent of resection, near-total or subtotal resection can be done wherever gross total resection (GTR) is not possible in NVCNS.

Looking Beyond the Anterolateral Skull Base with Frontotemporal Dural Fold Unlocking and Extradural Clinoidectomy: A Series of 17 Cases Deciphering the Translation from a Cadaver to Real, and Real to Pathologically Distorted Anatomy.

This article aims to discuss the surgical nuances and major adjustments necessary in unlocking the frontotemporal dural fold (FTDF) and extradural anterior clinoidectomy (EDAC) in actual cases, allowing translation from the cadaveric to a clinical scenario. We retrospectively reviewed the technical details of 17 procedures over 8 years, where both the initial steps (FTDF unlocking and EDAC) were performed. Lesions involving or extending to the anterolateral skull base, like the suprasellar cistern, optico-carotid cistern, interpeduncular cistern, petrous apex, and cavernous sinus, were included. The clinical data of the patients were retrieved retrospectively from the hospital information system (HIS) and in-patient records. This study was approved as a multicenter individual project with IEC No: 2020-342-IP-EXP-34. An illustrated note of the common steps and outcome of the 17 procedures of unlocking the FTDF and EDAC done is presented. The technique provided adequate exposure in performing aneurysmal clipping (posterior communicating artery [P. com], basilar top, and superior hypophyseal artery [SHA] aneurysm), giant pituitary adenoma (Wilson Hardy grade 4E, n = 2), fifth nerve schwannoma (n = 4), right Meckel's cave melanoma, cavernous hemangioma (n = 4), petroclival meningioma (n = 2), and clival chordoma. Temporary and permanent cranial nerve palsy as a procedure-related complication was seen in 11.8% (n = 2) each. Complete excision was achieved in 13 (n = 13/14) patients with tumors. FTDF unlocking and EDAC are elegant procedures providing reasonable access to the anterolateral skull base for myriad pathologies. Brain bulge, cavernous sinus bleeding, and losing the plane of dural duplication were significant challenges in switching from cadaveric to a clinical scenario.

Distal nerve transfer (PT-AIN, SUP-PIN) for regaining hand function in C8, T1 root injury following extirpation of the right C8, T1 schwannoma.

A 48-year-old female was admitted to the authors' department due to hand weakness as a consequence of C8, T1 root injury. Eight months earlier, the patient had been treated by a pulmonary surgeon due to an expansive lesion near the apex of the right lung, which resulted in right lower brachial plexus palsy. Postoperative pathohistological findings indicated that the lesion was nerve schwannoma. The diagnostic process included physical examination, electromyoneurography, and MRI. A distal nerve transfer (pronator teres-anterior interosseus nerve [PT-AIN], supinator-posterior interosseus nerve [SUP-PIN]) was performed in order to restore hand function. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID22110.

Schwannoma of the Sciatic Nerve – A case report

Schwannoma of the Sciatic Nerve – A case report

Carotid Body Tumor - radiological imaging and genetic assessment.

Carotid Body Tumor i.e. Paraganglioma is a challenging entity from the point of multidisciplinary diagnosis. The main treatment option i.e. surgery yields intraoperative risk,related to cranial nerve palsy and vascular morbidity.Bifurcation of Common Carotid Artery especially at the Carotid Body is the place where Head and Neck Paraganglioma is most frequently seen i.e. 60% of incidence [19]. Indeed, the knowledge of genetic germline SDH mutations, which cause deregulation of hypoxia-induced factors yields better understanding of the tumor nature. It is recommended to conduct selective neck dissection in regions IIA, IIB, III to exlude malignant transformation and metastasis, due to malignant potential of Carotid Body Tumors, especially in case of SDHB mutation. SDHD mutation is the main cause of hereditary HNPGLs. Computed tomography (CT), magnetic resonance imaging (MRI) and angiography yield thorough assessment of paraganglioma extension. In large size tumors, embolization of supplying artery under guidance of angiography may be considered. In case of Carotid Body Tumor, differential diagnosis should include: carotid artery aneurysm, lymphadenopathy, Schwannoma of the hypoglossal nerve or acessory thyroid gland.

Schwannoma of the submandibular gland: A rare case report

Schwannoma is a slow-growing, benign, encapsulated tumour of Schwann cells, which form myelin in peripheral nerve. It is the most common tumour of peripheral nerve, also known as neurilemma or neurinoma. Schwannomas of head and neck area are common and may arise from peripheral, central or autonomic nerve but salivary gland schwannomas are rare extracranial forms. The present study reports a rare case of schwannoma of the submandibular gland in a 42-year-old male patient which is presented with a painless mass in the submandibular region, treated by total excision of the submandibular gland. There were postoperative nerve deficit and no recurrence within 3months of follow up.

Neglected Giant Schwannoma of the Sciatic Nerve – A Case Report

Background: Schwannomas originating from the sciatic nerve are extremely rare and usually present as a pathological mass in palpable examination or pain located in the thigh. Motor and sensory deficits are observed more often when the size of the tumor is more than 40 mm.Case Description: A 19-years- old female patient was referred to Suez Canal University Hospital after 6 years of pain and 2 years of improper management. Neurological examination and MRI of the right thigh were done and revealed a huge mass attached to the right sciatic nerve. Surgical excision was undertaken, carefully dissecting the lesion from the sciatic nerve. Histopathological examination revealed the tumor to be a schwannoma. The patient had marked postoperative recovery with marked pain reduction and improved neurological deficits.Conclusions: Schwannomas of the sciatic nerve are rare tumors eccentrically located on the nerve. Although rare, schwannoma of the sciatic nerve should be systematically suspected if thigh mass or persistent sciatica is reported. Surgical excision has a good prognosis.

The Schwannoma of the facial nerve in the extra-skull segment – a case report

The aim of the report is to present a rare case of facial schwannoma in the parotid gland. Schwannomas are benign, well-defined tumors arising from Schwann cells that form myelin sheaths of peripheral, cranial or spinal nerves. 25-45% of them are located within the head and neck, mainly in the parapharyngeal space. The intraparotid location is rare. The etiology of cancer is unknown. Preoperative diagnosis, both radiological and cytological, is difficult and often does not give the correct diagnosis. Radiologically, a multiform adenoma is usually suspected, and the fine needle biopsy is non-diagnostic. Due to the rarity and benign nature of the tumor, there is a debate about the need for surgical treatment.

FV 5 Cubital Tunnel Syndrome (CuTS): Schwannoma of the ulnaris nerve caused numbness, paresthesia and cramps in the innervated digits

FV 5 Cubital Tunnel Syndrome (CuTS): Schwannoma of the ulnaris nerve caused numbness, paresthesia and cramps in the innervated digits

A Trigeminal Schwannoma Masked by Solely Vestibulocochlear Symptoms

Background: Intracranial schwannomas are most commonly associated with the vestibulocochlearnerve, often leading to hearing loss, tinnitus, and vestibular dysfunction. Much less often, a schwannomacan arise from the trigeminal nerve which can lead to facial pain, numbness, and weakness.<br />Purpose: We explored a case of a patient with an magnetic resonance imaging (MRI)-confirmed trigeminalschwannoma that was mistaken for a vestibulocochlear schwannoma because of a myriad of ipsilateralvestibulocochlear symptoms.<br />Research Design: This is a retrospective chart review and case study, with no statistics applied.<br />Results: This diagnostic error led to clinical confusion and inaccurate medical record-keeping. Radiologistsand radiation oncologists deemed the patient’s symptoms to be unrelated to the asymptomatictrigeminal schwannoma, and she was referred to an otolaryngologist following complaints of ear fullness,ear pain, and hearing loss. The patient’s audiogram showed ipsilateral, asymmetric sensorineural hearingloss, and she was diagnosed with concurrent Meniere’s disease. Alternative explanations, such as anadditional schwannoma or external compression of the vestibulocochlear nerve, were considered, but notapparent on MRI.<br />Conclusions: From this case, we see that symptoms do not always concur with imaging results and thatmultiple etiologies, especially when one is rare, can confuse a clinical picture.<br />

Vestibular findings in patients with schwannoma of the 8th cranial nerve: a survey of nine cases and review of the literature

Introduction: Some aspects of the natural history of vestibular schwannoma (VS) remain unsettled. A better understanding of the pathophysiology of the disease would improve its diagnostic workup and therapeutic management, as VS often requires surgery, which carries the risk of severe complications. This paper discusses the significance of ultrastructural findings in the vestibular organs removed during surgery.Material and methods: This study examined specimens from vestibular organs removed from patients who underwent VS resection through the translabyrinthine approach. The sample includes 9 patients, seven women and two men, with a mean age of 55 years (range 39–71 years).Results: The sensory epithelium showed a loss of stereocilia, numerous lipofuscin granules and vacuoles in the cytoplasm. The subepithelial myelinated nerve fibres showed signs of demyelination and sheath rearrangement. Some axons had markedly degenerative modifications, with neurofilament aggregation, more numerous mitochondria and vacuolization. As it lost its specialized structures, the epithelial covering of the semicircular canal walls progressively flattened out in the area farthest away from the sensorial area.Conclusions: There were no specific correlations between schwannoma size and instrumental or ultrastructural findings in the vestibular epithelium organs. The morphological features of the non-sensory epithelium suggest that the potassium circulation system is preserved in patients with VS even when they present prominent cochlear and/or vestibular symptoms. VS formation appears to be multifactorial; the vestibular nerve conduction block caused by tumour compression would not necessarily cause irreversible damage to the vestibular receptors at the outset.

Melanin in human vestibular organs: what do we know now? An ultrastructural study and review of the literature

Objective: Melanin is a pigment widely found in animals and plants. It has long been observed in the inner ear, but its function there is not even now entirely clear. The protective role of melanin against damage caused by ageing, ototoxicity and noise is still a matter of debate.Methods: The current study discusses ultrastructural findings in the vestibular organs removed via the translabyrinthine approach for the resection of a schwannoma of the 8th cranial nerve. Our aim was to shed more light on the role of melanocytes in the inner ear, analyzing their features in human subjects.Results: Melanin granules were present in all of the cases studied: in some samples they appeared scattered in the cytoplasm, whereas in others they accumulated in the reserve area. There was no correlation between the presence of pigment and schwannoma dimensions other than a greater frequency of accumulation in the reserve areas in the melanocytes of patients with small tumours.Conclusions: Our findings and literature data confirm that melanocytes are an integral part of the endolymph production system and appear essential for balance and hearing functions, having a protective effect. Thanks to its semiconducting properties, melanin could be involved in absorbing the mechanical energy arising from sensory stimulation.

Schwannoma of the Median Nerve at the Wrist- A Case Report and Review of Literature

Schwannoma of the Median Nerve at the Wrist- A Case Report and Review of Literature

Incomplete High Radial Nerve Palsy Due to Schwannoma of Radial Nerve in the Upper Arm—A Case Report

A schwannoma is a benign soft tissue tumor composed of Schwann cells. Clinically, the tumor is slow-growing and usually asymptomatic, rarely developing neurological symptoms. We present a case of a 44-year-old female who was diagnosed with an incomplete high radial nerve palsy, showing a wrist drop and extension of fingers due to schwannoma on the radial nerve of the upper arm. The patient showed excellent result after excision of the schwannoma and neurorrhaphy of the radial nerve.

Schwannoma of the median nerve

Schwannoma of the median nerve

Stereotactic radiosurgery for non-vestibular cranial nerve schwanommas.

Non-vestibular cranial nerve schwannomas (NVCNS) are rare lesions, representing <10 % of cranial nerve schwannomas. The optimal treatment for NVCNS is often derived from vestibular schwannomas experience. Surgical resection has been referred to as the first line treatment for those benign tumors, but significant complication rates are reported. Stereotactic radiosurgery (SRS) has arisen as a mainstay of treatment for many benign tumors, including schwanommas. We retrospectively reviewed the outcomes of NVCNS treated by SRS to characterize tumor control, symptom relief, toxicity, and the role of hypo-fractionation of SRS dose. Eighty-eight (88) patients, with ninety-five (95) NVCNS were treated with either single or multi-session SRS from 2001 to 2014. Local control was achieved in 94 % of patients treated (median follow-up of 33 months, range 1-155). Complications were seen in 7.4 % of cases treated with SRS. At 1-year, 57 % of patients had improvement or resolution of their symptoms, while 35 % were stable and 8 % had worsening or increased symptoms. While 42 % received only one session, results on local control were similar for one or multiple sessions (p = 0.424). SRS for NVCNS is a treatment modality that provides excellent local control with minimal complication risk compared to traditional neurosurgical techniques. Tumor control obtained with a multi-session treatment was not significantly different from single session treatment. Safety profile was also comparable for uni or multi-session treatments. We concluded that, as seen in VS treated with CK SRS, radiosurgery treatment can be safely delivered in cases of NVCNS.

A case of multiple schwannomas in nerves of the lower extremities

Schwannoma, also known as neurilemma, is a rare benign tumor on a nerve sheath consisting of Schwann cells and a capsule. These tumors are the most common peripheral nerve tumors. Their manifestation is often a single swelling across the nerve, yet there may be more than one lesion in Neurofibromatosis type 2 cases. The present work discusses a case of multiple schwannomas developing in both sensory and motor nerves simultaneously with involvement of three different nerves in a non-syndromic patient.