Lower Cranial Nerve Schwannomas Research Articles

Prevalence and natural history of schwannomas in neurofibromatosis type 2 (NF2): the influence of pathogenic variants.

This study explores the natural history of vestibular, trigeminal and lower cranial nerve schwannomas (VS, TS, LCNS) in patients with Neurofibromatosis type 2 (NF2), to understand how pathogenic variants (PVs) of the NF2 gene affect tumour burden and growth rate, viaa retrospective analysis of a UK NF2 centre database and imaging. VS, TS and LCNS location and size were measured in accordance with a standardised protocol. PVs were categorised in accordance with the UK NF2 Genetic Severity Score (GSS). 153 patients (age 5-82) had 458 schwannomas, of which 362 were previously untreated comprising: 204 VS, 93 TS, and 65 LCNS (IX, X, XI). 322 schwannomas had sequential imaging allowing growth rate analysis with a mean follow-up of 45 months. VS were universally present, and bilateral in 146/153 cases. 65% of tumours grew >2 mm during the study period at mean rate 2.0 mm/year. Significant association was found between increasing GSS and growth rate. TS occurred in 66/153 patients (bilateral in 27/153); 31% of tumours showed growth (mean 1.8 mm/yr). Significant increase in tumour prevalence was noted with increasing GSS. LCNS were found in 47/153 patients (bilateral in 19/153); 27% of tumours showed growth (mean 1.9 mm/yr). The trend for increased prevalence with increasing GSS did not reach significance. VS growth rate was significantly influenced by GSS and they were much more likely to grow than TS and LCNS. TS prevalence also correlated with increasing GSS.

Simplifying the Surgical Classification and Approach to the Posterolateral Skull Base and Jugular Foramen Using Anatomical Triangles.

IntroductionLesions of the jugular foramen (JF) and postero-lateral skull base are difficult to expose and exhibit complex neurovascular relationships. Given their rarity and the increasing use of radiosurgery, neurosurgeons are becoming less experienced with their surgical management. Anatomical factors are crucial in designing the approach to achieve a maximal safe resection.Methods and methodsSix cadaveric heads (12 sides) were dissected via combined post-auricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. Contiguous surgical triangles were measured, and contents were analyzed. Thirty-one patients (32 lesions) were treated surgically between 2000 and 2016 through different variations of the retro-auricular distal cervical transtemporal approaches.ResultsWe anatomically reviewed the carotid, stylodigastric, jugular, condylar, suboccipital, deep condylar, mastoid, suprajugular, suprahypoglossal (infrajugular), and infrahypoglossal triangles. Tumors included glomus jugulare, lower cranial nerve schwannomas or neurofibromas, meningiomas, chondrosarcoma, adenocystic carcinoma, plasmacytoma of the occipitocervical joint, and a sarcoid lesion. We classified tumors into extracranial, intradural, intraosseous, and dumbbell-shaped, and analyzed the approach selection for each.ConclusionJugular foramen and posterolateral skull base lesions can be safely resected through a retro-auricular distal cervical lateral skull base approach, which is customizable to anatomical location and tumor extension by tailoring the involved osteo-muscular triangles.

SURGERY OF JUGULAR FORAMEN LESIONS - AN INSTITUTIONAL EXPERIENCE

Jugular foramen tumors are rare skull base tumors having complex neurovascular anatomy. Most common being paragangliomas, lower cranial nerve schwannomas and meningiomas. Being the conduit for important neuro-vascular structures, potential complications following surgery are a frequent source of morbidity. Retrospective study done from March 2008 to September 2014. All patients underwent highresolution computer tomography (HRCT) of temporal bones and magnetic resonance imaging (MRI) with angiography in pre-operative period. Surgical approach and pre-operative endovascular intervention depended on the site and extent of the lesion. Extent of tumor removal was determined at the time of surgery. Patients with incomplete excisions in postoperative imaging were subjected to radiotherapy depending on histo-pathological diagnosis. Total of 22 patients of jugular foramen lesion were operated. Histopathological diagnosis included paraganglioma(n=18), schwannomas(n=2), p l a s m a c y t o m a ( n = 1 ) , s q u a m o u s c e l l carcinoma(n=1). Eighth cranial nerve was the most common involved nerve preoperatively (100%). Infratemporal Fossa approach, along with its modication, and conservative jugulopetrosectomy approach were used for surgical excision as per the extent of tumor. Complete excision was done in 73% (n=16), and postoperative radiotherapy was given to rest of the patients. The most common postoperative complication was lower cranial nerve decit in immediate post op period(n=15, 68%) (new onset n= 3, 13% and n=12, 55% had preoperative paresis), on follow up lower cranial nerve palsy improved in 50% in follow up (n=7). Most common tumor of the jugular foramen was paraganglioma followed by lower cranial nerve schwannoma. Surgical management depends on the extent of tumor. Multidisciplinary approach provides better patient outcome. Histopathological diagnosis aids to give targeted radiotherapy to the local site, and hence surgical excision of JFT(Jugular foramen tumor) is recommended.

Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas.

Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically similar locations. Methods We performed a retrospective review of all patients who received GK-SRS for glomus jugulare tumors and lower cranial nerve schwannomas at our institution between 2006 and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression techniques were employed using SPSS. Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13-18 Gy) and 12.5 Gy (range 12-14 Gy), respectively. All except one patient had tumor control at last follow-up visit. No worsening of pre-existing neurological deficits was observed. There were seven patients who developed any new neurological deficit after GK-SRS, four from the glomus group, and three from the schwannoma group (20 and 50% of each group, respectively). Only two of seven patients had permanent new neurological deficits. Both of them were in the schwannoma group. Univariate analysis showed that only a diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication after GK-SRS compared with diagnosis of glomus jugulare ( p = 0.046). Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma group compared with the glomus group.

Lower Cranial Nerve Schwannomas: Microsurgical Outcomes in a Modern Cohort

Lower Cranial Nerve Schwannomas: Microsurgical Outcomes in a Modern Cohort

Accessory Nerve Schwannoma Extending to the Foramen Magnum and Mimicking Glossopharyngeal Nerve Tumor—A Case and Review of Surgical Techniques

Background: Intracranial schwannomas of the accessory nerve are very rare lesions. They are categorised according to their locations into either intrajugular or intracistemal schwannomas although most of them are intrajugular. The intrajugular type constitutes about 2% to 4% of all intracranial schwannomas described in literature. Aim: It’s very unusual for an accessory nerve to mimic glossopharyngeal nerve looking at the anatomical location of the accessory nerve. Although many authors have written on accessory nerve, none have described this unusual presentation. We present a case, management as well as review on the classification and appropriate surgical techniques we could have use to access the tumor in our patient since the choice of a particular surgical approach is based on the nature of tumor, location as well as it extension into other adjacent structures. Case Presentation: We present a case of 52-year-old woman with very unusual accessory nerve schwannoma which mimics the clinical presentation of glossopharyngeal nerve tumor. The main symptom in our case is six (6) months history of deviation of the tongue to right side with dizziness and change of voice. Conclusion: The unusual presentation in our case could be due to massive compression of glossopharyngeal nerve by the growing accessory nerve schwannoma since most lower cranial nerve schwannomas at this location will almost always course compressive symptoms.

Meningioma in the Middle Ear: An Unusual Case of Hearing Loss

Meningioma in the Middle Ear: An Unusual Case of Hearing Loss

Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas

Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas

Management of multiple tumors in neurofibromatosis type 2 patients

IntroductionNeurofibromatosis type 2 is characterized by the presence of bilateral vestibular schwannomas. However, other nervous system tumors may also occur. Therefore, the management of NF2 patients is complex and requires a multidisciplinary discussion in a specialized center. Materials and methodsAll recent articles concerning tumors other than vestibular schwannoma in NF2 disease were reviewed, using PubMed databases. ResultsIntracranial meningiomas occur in 50% of NF2 patients, and are often multiple. Surgery remains the main treatment and should be performed in cases of growing tumors. The role of antiangiogenic therapy is currently under evaluation and the role of radiosurgery still remains to be defined in NF2 disease. Spinal tumors occur in about half of NF2 patients. Surgery should be discussed when radiological tumor progression is demonstrated, even if spinal tumors are asymptomatic, in order to preserve neurological function and good quality of life. As regards lower cranial nerve schwannomas, radiosurgery appears to be a more appropriate treatment for growing tumor with a small volume in order to avoid post-operative complications, especially swallowing disorders. Facial nerve schwannomas may appear, on MRI, like vestibular schwannomas. The diagnosis should be suspected when the facial palsy is an early symptom during cerebello-pontine tumor progression. Trigeminal schwannomas are frequent in NF2 disease and fortunately they are often asymptomatic. Among major neurofibromatosis types, peripheral nerve sheath schwannomas are only present in patients with NF2 disease and schwannomatosis. Surgical resection is required when the cutaneous schwannomas is painful or when tumor progression is observed and causes symptoms. ConclusionTumors other than vestibular schwannoma are also associated with a poor prognosis in NF2 patients. Surgery remains the main treatment in most cases. Each treatment decision in NF2 disease requires a complete evaluation of all cranial and spinal locations of the disease in order to establish surgical priorities and strategies.

下位脳神経鞘腫のガンマナイフ治療

下位脳神経鞘腫のガンマナイフ治療の長期成績を報告した. 症例は男性11, 女性22例の計33例であり, 平均年齢は47.3歳であった. 多くの症例は下位の脳神経の神経症状として, 嚥下障害, 嗄声, 舌の萎縮などを示した. 前治療として17例には手術的摘出が施行されていたが, 16例については神経症状と画像所見により診断した. ガンマナイフ時の腫瘍サイズは平均して25mmであり, 平均の辺縁線量13.3Gyで治療されている. 治療後, 腫瘍は良好な反応を示し, 83カ月の平均経過観察期間においてCR 1, PR 23, NC 9となった. 2例において経過観察中, 嚢腫の増大が認められたが, 嚢腫の処理によって再度安定しNCとなった. その他, どの症例にも明らかな副作用は認められていない. 機能的には嚥下障害, 嗄声の症状は多数例において改善したが, 舌の萎縮, 聴力障害, 失調などは不変であった. 治療全体を総合的に判断できるよう神経鞘腫のスコアリングを提示した. 腫瘍コントロールに4点, 機能コントロールに4点, 副作用回避に2点, 合計10点満点でみると, ガンマナイフ治療において, 下位脳神経鞘腫は他の神経鞘腫に比べ点数が最も高く, 質の高い治療が達成されたと判断した. 大きな腫瘍, 頭蓋内, 錐体部, 頚部に進展するdumbbell-typeの腫瘍では外科的摘出が必要であるが, 頚静脈孔内, あるいはその近傍の腫瘍, あるいは残存, 再発腫瘍に対してはガンマナイフ治療がきわめて有効である.

Jugular Foramen Tumors

To describe the diagnosis, management, and treatment outcome of jugular foramen (JF) tumors. Retrospective chart review. Charts of the 83 patients diagnosed with JF tumors between January 1997 and May 2008 were reviewed. Presenting symptoms, otologic and neurotologic examination, audiologic thresholds, treatment procedure, surgical technique, tumor size and classification, and postoperative complications were recorded. Facial nerve function was graded using the House-Brackmann scale. Extent of tumor removal was determined at time of surgery, followed by routine radiographic follow-up. The mean age of patients with JF tumors was 48.5 years (standard deviation, 16.3 yr), and women (79.5%) outnumbered men (20.5%). Most had glomus jugulare (GJ) tumors (n = 67, 80.7%); 9 patients had lower cranial nerve schwannomas (10.8%), and 7 patients had meningiomas (8.4%). The most frequent initial symptoms included pulsatile tinnitus (84.3%), conductive hearing loss (75.9%), and hoarseness (34.9%). Sixty-one patients (73.5%) underwent surgery, 18.1% had radiotherapy, and 8.4% were observed. Total tumor removal was achieved in 81% of surgery cases. New lower cranial nerve (CN) deficits occurred after surgery in 18.9% of GJ, 22.2% of schwannoma, and 50% of the 4 meningiomas. At last follow-up, 88.1% of surgical patients had normal or near-normal (House-Brackmann I or II) facial function. Total resection of GJ tumors, meningiomas, and lower CN schwannomas can be a curative treatment. However, subtotal removal may be required to preserve CN function, vital vascular structures, and the brainstem. Postoperative radiotherapy is used to control residual tumor. When postoperative complications develop in patients, early rehabilitation is important to decrease mortality and morbidity. Therefore, patients should be closely followed.

Fatal delayed post-operative cerebral venous thrombosis after excision of hypoglossal nerve schwanomma

Lower cranial nerve schwannomas are rare tumours. We present a 35 year old female patient who had a lower cranial nerve schwannoma with both intracranial and extracranial components. The internal jugular vein was injured during the dissection of the extracranial portion of the tumour. Ligation of the internal jugular vein is not associated with significant post-operative complications. Our patient however, developed retrograde cortical venous thrombosis on the 14(th) post-operative day resulting in multiple areas of haemorrhagic venous infarction with raised intracranial pressure. Such a delayed contiguous cortical venous thrombosis has not been reported. We present this report to highlight this event and to outline the probable causes for the same.

Distribution of Nonvestibular Cranial Nerve Schwannomas in Neurofibromatosis 2

To describe the prevalence and location of cranial nerve schwannomas, other than bilateral vestibular schwannoma, in patients with neurofibromatosis 2 (NF2). The NF2 Natural History Consortium prospectively gathered cranial magnetic resonance imaging for 83 patients across 3 annual evaluations. The time between the first and last evaluation was approximately 3 years. Forty-two patients (51%) had nonvestibular cranial nerve schwannomas (NVSs). Of these, 25 (60%) also had cranial meningiomas. Twenty-one of those without NVS (25% of 83) had at least 1 meningioma. The average size of the NVS was 0.4 cubic centimeters. Overall, there was no significant change in NVS size from Year 1 to Year 3 or from Year 1 to Year 2. The most common locations of the NVS were occulomotor and trigeminal. A family history of NF2 did not predict NVS location or growth. Nonvestibular cranial nerve schwannoma usually affect cranial nerves III and V, as was the case in our NF2 sample. Fortunately, neuropathies associated with these tumors are rare. In contrast, lower cranial nerve schwannomas, although also rare, are associated with swallowing difficulty, aspiration, and other sequelae.