Magnetic resonance imaging of the cerebellopontine angle: comparison between constructive interference steady-state and small field-of-view technique turbo spin echo sequences.

BACKGROUND: The aim of this work was to optimize a three-dimensional (3D) turbo-spin-echo (TSE) sequence using a small field-of-view (FOV) technique for the study of the cerebellopontine angle and to compare it with a constructive interference steady-state (CISS) sequence. METHODS: A total of 30 consecutive patients underwent magnetic resonance imaging with a 3Tesla (T) scanner, including 3D CISS and the optimized 3D small FOV technique turbo spin echo (3D SFT-TSE) T2-weighted sequences for the study of the cerebellopontine angle. The 3D SFT-TSE sequence was optimized after three different steps, and a quantitative evaluation of the signal-to-noise ratio (SNR) was obtained according to the National Electrical Manufacturers Association (NEMA) method. Three neuroradiologists made a blind comparative qualitative evaluation of the images between the 3D CISS and the 3D SFT-TSE obtained after the third optimization step, based on spatial resolution, contrast resolution, and presence of artifacts and noise. RESULTS: The calculation of SNR using the NEMA method confirmed the superiority of the third optimization step over the others. For both spatial and contrast resolution, the optimized SFT-TSE was considered better (p < 0.001) than the CISS, while image artifacts and noise were considered worse in the CISS sequence (p < 0.001). Intraobserver analysis showed that all neuroradiologists preferred the 3D SFT-TSE sequence in terms of both spatial resolution and contrast resolution and found more noise and artifact disruption in the CISS sequence. CONCLUSIONS: The use of the 2D radiofrequency pulse technique with a 3D SFT-TSE T2 sequence was significantly more efficient than the 3D CISS sequence for the study of the cerebellopontine angle and inner ear structures.

Fully Endoscopic Retrosigmoid Approach for Cerebellopontine Angle Tumors.

BACKGROUND: Fully endoscopic or endoscope-controlled approaches are essentially keyhole approaches in which rigid endoscopes are the sole visualization tools used during the whole procedure. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Fully endoscopic retrosigmoid approach for cerebellopontine angle tumors is a minimally invasive approach that is not routinely practiced by neurosurgeons, with few series published so far. Unfamiliarity with the technique, steep learning curve, and concerns about inadequate exposure, neurovascular injury, and decreased visibility may explain this fact. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic retrosigmoid approach and present an overview of the published series. METHODS: From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic retrosigmoid approach for cerebellopontine angle tumors were retrieved and analyzed. The pertinent literature was also reviewed. RESULTS: The surgical technique of the fully endoscopic retrosigmoid approach was formulated. CONCLUSION: The endoscopic technique has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Surgical Outcomes and Predictive Factor Analysis for Facial Nerve Preservation in Patients With Cerebellopontine Angle (CPA) Tumors: A Ten-Year Single Institutional Study.

Objective To analyze the surgical outcome and predictive factors for facial nerve preservation in patients with surgically operated cerebellopontine angle (CPA) tumors. Methodology Methodology Data were retrospectively retrieved from inpatient medical records of patients admitted with CPA tumors from January 1, 2011, to December 31, 2020, at our institute. Epidemiological, clinical and radiological findings, histopathological types, surgical outcomes, and facial nerve function of these patients were recorded using a data-gathering tool. Results Out of 230 patients, 188 (81.7%) were diagnosed histopathologically with vestibular schwannoma (VS), 20 (8.7%) with meningioma, 15 (6.5%) with epidermoid, and 7 (3.1%) with other conditions. The most common clinical features were hearing loss in VS and headaches in meningioma and epidermoid. Preoperatively, 103 (44.8%) had grade 2, 68 (29.6%) had grades 3 or 4, and 8 (3.5%) had grade 5 facial nerve palsy, while post-operatively, 93 (40.9%) patients had grade 2, 83 (36.6%) had grades 3 or 4, and 6 (2.6%) had grade 5 facial palsy. Greater facial nerve preservation was observed in patients with tumor sizes <4 cm (p=0.0041) and in those who underwent near-total (NTR) or subtotal resection (STR) (p=0.0442). Excellent facial nerve outcomes (HB grades 1 or 2) were noted in patients who underwent intraoperative facial nerve monitoring (p<0.0001). CSF leak and meningitis were present in 3.5% and 2.2% of patients, respectively. The mortality rate was 6.1%, with a recurrence rate of 4.8%. Conclusion Intraoperative facial nerve monitoring, tumor size less than 4 cm, and extent of resection (NTR/STR) are predictive factors that significantly affect facial nerve outcomes.

Creeping through the cranium: A rare and interesting presentation of a meningioma.

A meningioma is a rare primary CNS tumor that tends to present more so in females in a slowly progressive fashion. The cavernous sinus and cerebellopontine angle are uncommon locations for meningiomas. We present a case of a meningioma in a 60-year-old female presenting to the emergency department for a sudden onset headache, vertigo, facial paresthesias, and chest pain. Inpatient workup revealed orthostatic hypotension, a meningioma spanning from the left cavernous sinus to the left cerebellopontine angle encasing the left cavernous internal carotid artery on MRI and CTA, and an incidental 12 mm calcified fibroadenoma on CT. Hospital course consisted of supportive treatment, physical rehabilitation, and review of previous imaging to determine need for intervention per consultants' recommendations. The patient was discharged with an antiplatelet, an antihistamine, appropriate additional medications, a vestibular therapy script, and outpatient referrals for a decision regarding surveillance and intervention. Overall, this case describes some key points. It demonstrates that cavernous sinus and cerebellopontine angle meningiomas can occur simultaneously, especially as a continuous mass, which very few cases have done so far. It also highlights an acute clinical presentation of a meningioma, contrary to the gradually progressive one observed in most instances. Last, but not least, it shows how nonspecific symptoms can lead to unique findings at times.

Prevalence of Anterior Inferior Cerebellar Artery Vascular Loop in Cerebellopontine Angle With Three-Dimensional Constructive Interference in Steady State (CISS) Sequence MRI.

Background The cerebellopontine angle (CPA) cistern houses vital neurovascular structures such as cranial nerves V, VII, and VIII and the anterior inferior cerebellar artery (AICA), often leading to neurovascular compression syndromes due to its complex anatomy. Although vascular compression is a recognized cause of certain neuralgias, its association with otologic symptoms such as tinnitus, hearing loss, and dizziness remains uncertain. Hence, this study aims to determine the prevalence of the AICA vascular loop in the CPA cistern on MRI in patients with asymptomatic audiovestibular symptoms. Methodology Adult patients who underwent MRI, including the posterior fossa's high-resolution volumetric T2 sequence (three-dimensional constructive interference in steady state (3D-CISS)), were assessed. Patients with a history of audiovestibular symptoms (tinnitus/dizziness/vertigo/sensorineural hearing loss), intracranial tumor, vascular lesions, intracranial surgery, brain radiation therapy, traumatic brain injury, poor image quality, and MRI scans without 3D-CISS sequences were excluded. Two radiologists independently reviewed 114 (228 sides) MRI studies for the vascular loop of AICA in the CPA cistern and the extension of the AICA loop into the ipsilateral internal acoustic meatus which was graded by Chavda's classification. Results The prevalence of vascular loop of AICA in the CPA cistern was as high as 47.6% in asymptomatic patients. Grade I Chavda vascular loop was the most common type followed by type II, with type III being the least common type. Conclusions Knowledge regarding the high prevalence of the AICA loop in the asymptomatic population and the lack of significant correlation between the presence of the AICA loop and otovestibular symptoms should be considered in preoperative planning for decompression procedures.

Clinicopathological characteristics of secondary trigeminal neuralgia due to cerebellopontine angle tumors. / æ¡¥å°è„‘è§’è‚¿ç˜¤ç»§å‘æ€§ä¸‰å‰ç¥žç»ç—›çš„ä¸´åºŠç— ç†ç‰¹å¾.

OBJECTIVES: Cerebellopontine angle (CPA) tumors are a common cause of secondary trigeminal neuralgia (TN), characterized by their concealed location, slow progression, and difficulty in early detection. This study aims to explore the clinicopathological characteristics of patients with secondary TN due to CPA tumors to enhance understanding and management of secondary TN. METHODS: A retrospective analysis was conducted on clinical data and pathological results of 116 patients with CPA tumor-related TN treated at Xiangya Hospital of Central South University from January 1, 2017 to December 31, 2022. The study analyzed the relationship of tumor pathological types with clinical manifestations, tumor location, surgical methods, and treatment outcomes. RESULTS: Among the cases, 95.7% (111/116) were benign tumors, 3.4% (4/116) were malignant tumors, and 0.9% (1/116) were borderline tumors. Benign tumors were predominantly acoustic neuromas, meningiomas, and schwannomas. Among the patients, 46.6% (54/116) presented with isolated TN, while 53.4% (62/116) exhibited other associated symptoms depending on factors such as tumor growth location and rate. The complete resection rate in this group was over 90%, with 41.4% (48/116) of patients undergoing concurrent microvascular decompression after tumor resection, predominantly for schwannomas. The overall effective rate of surgical treatment reached 93.9%, with schwannomas showing higher efficacy rates compared with acoustic neuromas and meningiomas (P<0.05). The recurrence rate of acoustic neuromas was significantly higher than that of meningiomas and schwannomas (P<0.05). CONCLUSIONS: CPA tumors are a major cause of secondary TN, predominantly benign, with occasional underdiagnosed malignant tumors. Early diagnosis and treatment significantly impact prognosis. Different tumor types vary in clinical symptoms, surgical approaches, and treatment efficacy. Surgical strategies should balance tumor resection extent and neural function preservation, with microvascular decompression as necessary.

Facial nerve electrical motor evoked potential in cerebellopontine angle tumors for its anatomical and functional preservation.

Background: Among the technical measures to preserve facial nerve (FN) function, intraoperative neuromonitoring has become mandatory and is constantly being scrutinized. Hence, to determine the efficacy of FN motor evoked potentials (FNMEPs) in predicting long-term motor FN function following cerebellopontine angle (CPA) tumor surgery, an analysis of cases was done. Methods: In 37 patients who underwent CPA surgery, FNMEPs through corkscrew electrodes positioned at C5-C6 and C6-C5 (C is the central line of the brain as per 10-20 EEG electrode placement) were used to deliver short train stimuli and recorded from the orbicularis oculi, oris, and mentalis muscles. Results: In 58 patients, triggered electromyography (EMG) was able to identify the FN during resection of tumor, but 8 out of these (4.64%) patients developed new facial weakness, whereas 3 out of 38 (1.11%) patients who had intact FN function MEP (decrement of FN target muscles - CMAPs amplitude peak to peak >50-60%), developed new facial weakness (House and Brackmann grade II to III). Conclusion: The FNMEP has significant superiority over triggered EMG when tumor is giant and envelops the FN.

Role of Neuroradiological Imaging in Progressive Sensorineural Hearing Loss: A Retrospective Study.

Aim: Our aim was to determine prevalence and type of neuro-radiological lesions detected on screening Magnetic Resonance Imaging (MRI) of brain in patients presenting with progressive sensorineural hearing loss in otorhinolaryngology clinic. Materials and Methods: This retrospective study included 96 screening magnetic resonance imaging MRI brain scans of patients who presented with progressive sensorineural hearing loss in department of otorhinolaryngology. The clinical and radiological data was collected and analysed. Results: Out of 96 screening MRI brain, 19 (19.8%) had positive findings. The commonest imaging finding was presence of vascular loop around facial and vestibulocochlear nerve root complex in 9 cases (9.4%) followed by presence of a cerebellopontine angle lesions in 5 cases (5.2%). The mean age of all patients was 48.5 years and those with positive screening MRI was 40.6 years. A gender gap was noticed with female being 22 (22.9%) in number against 74 (77.1%) males. Conclusion: This is the first retrospective study to determine prevalence and type of neuro-radiological lesions detected on screening magnetic resonance imaging in patients with progressive sensorineural hearing loss. We recommend screening MRI brain in patients with progressive SNHL aged below 60 years and all the described neuroradiological finding provide differential diagnosis. Definition and classification of progressive sensorineural hearing loss should be formulated to standardize the management. Further multi-institutional studies are required to identify social, occupational, genetic, or other factors that can cause gender disparity in patients with progressive SNHL.

Arteriovenous malformations in the cerebellopontine angle: assessment of the "backdoor resection" technique and microsurgical results in 38 patients.

OBJECTIVE: Posterior fossa arteriovenous malformations (AVMs) represent 7% to 15% of all intracranial AVMs and are associated with an increased risk of hemorrhage, morbidity, and mortality compared with supratentorial AVMs, thus prompting urgent and definitive treatment. Cerebellopontine angle (CPA) AVMs are a unique group of posterior fossa AVMs incorporating characteristics of brainstem and cerebellar lesions, which are particularly amenable to microsurgical resection. This study reports the clinical, radiological, operative, and outcome features of patients with CPA AVMs in a large cohort. METHODS: The authors conducted a single-surgeon, 2-institution retrospective cohort study of all consecutive patients with CPA AVMs treated with microsurgical resection during a 25-year period. RESULTS: CPA AVMs represented 22% (38 of 176) of all infratentorial AVMs resected by the senior author. Overall, 38 patients (22 [58%] male and 16 [42%] female) met the study inclusion criteria and were analyzed. Most patients presented with hemorrhage (n = 29, 76%). The median age at surgery was 56 (range 6-82) years. Subtypes included 22 (58%) petrosal cerebellar AVMs, 11 (29%) lateral pontine AVMs, and 5 (13%) AVMs involving both the brainstem and cerebellum. Most AVM niduses were small (< 3 cm; n = 35, 92%) and compact (n = 31, 82%). Fourteen (37%) patients harbored flow-related aneurysms. Twenty (53%) patients underwent preoperative embolization. Complete angiographic obliteration was achieved with microsurgery in 35 (92%) patients. Five (13%) patients with poor neurological conditions at presentation died before hospital discharge. Of the 7 (18%) patients with new postoperative neurological deficits, 5 had transient deficits. The median (interquartile range) follow-up was 1.7 (0.5-3.2) years; 32 (84%) patients were alive at last follow-up, and 30 (79%) had achieved a favorable neurological outcome (modified Rankin Scale [mRS] score 0-2). The only independent predictor of unfavorable postoperative outcome (mRS score 3-6) was the preoperative mRS score (p = 0.002). CONCLUSIONS: CPA AVMs are unique posterior fossa lesions, including petrosal cerebellar and lateral pontine AVMs. The "backdoor resection" technique provides a safe and efficient strategy with high obliteration rates and a low risk of treatment-related morbidity. Microsurgical resection should be considered the frontline treatment for most CPA AVMs, except for those with a significant diffuse brainstem component.

A Case Report of Malignant Cerebellopontine Angle Lesion Highlighting the Interdisciplinary Diagnostic Challenge in the Case of Unilateral Progressive Hearing Loss.

The authors present the case of a young boy who experienced progressive unilateral hearing loss initially believed to be unrelated to any other medical condition. Methods: The patient received a thorough evaluation, which included a comprehensive battery of audiological tests, a CT scan, and a gadolinium-enhanced MRI. Results: A repeated imaging investigation revealed the presence of a mass that mimicked a vestibular schwannoma (VS), but despite this, the boy was ultimately diagnosed with cerebral manifestations of B-cell acute lymphoblastic leukemia (B-ALL). Conclusions: Cerebral lesions originating from the internal auditory canal are rare in cases of B-ALL. In this case, the initial signs and symptoms of the disease were solely related to the audiovestibular system, making the diagnostic process particularly complicated. Unilateral hearing loss cases may indicate the presence of potentially life-threatening conditions, even if the hearing loss appears to be clinically non-syndromic. For these reasons, unilateral hearing losses necessitate a comprehensive interdisciplinary diagnostic approach from the very start of auditory manifestation and, in particular, if the hearing impairment demonstrates threshold progression.

Exoscopic Retrosigmoid Approach for an Anteromedial Tentorial Meningioma: 2D Operative Video.

We present a 2-dimensional operative video (Video 1) of a suboccipital retrosigmoid approach for an anteromedial tentorial meningioma with a specific focus on the use of a surgical exoscope. The patient is a 50-year-old woman who presented to emergency room with a 6-month history of nausea, dizziness, and gait imbalance secondary to a 2.5-cm homogenously enhancing mass originating from the anteromedial tentorium on the right side with associated brainstem compression. Retrosigmoid craniotomy was selected due to the favorable surgical corridor for resection and lower risk of cerebrospinal fluid leak, hearing loss, and seizures compared with other approaches.1-5 The patient consented to the procedure. Video 1 emphasizes the advantages of the exoscope compared with the microscope in optimizing surgeon efficiency, ergonomics, and comfort.6 The unique operating room setup associated with exoscope use is highlighted. The patient underwent uncomplicated gross total resection with a mild trochlear nerve palsy noted postoperatively that was resolved at follow-up.7.

Expanding the spectrum on brain-heart interactions in cerebellopontine angle surgeries.

Lesions at the cerebellopontine angle (CP angle) are associated with various brain-heart interactions, which can include those from stimulation of the fifth cranial nerve along the scalp incision in a retrosigmoid suboccipital surgical approach. A 27-year-old male patient with recently diagnosed hypertension (on calcium channel blocker) underwent left CP angle lesion decompression. Transient episodes of bradycardia, hypotension, and bradypnea were observed from the skin incision onward, exacerbated during tumor manipulation. Most episodes subsided with cessation of the surgical stimulus while some required intervention. Postoperatively, blood pressure decreased below the pre-operative levels. Thus, trigeminocardiac reflex can occur as early as the skin incision even in a retrosigmoid approach due to stimulation of the mandibular division, when specific risk factors exist. Such episodes may serve as early warning signs for subsequent intraoperative occurrences. Brainstem compression can be a possible etiology of hypertension in young patients. It underscores the importance of considering brain-heart interactions in surgical interventions involving the CP angle.

Spontaneous Regression of a Large Vestibular Schwannoma: Is Nonoperative Management Reasonable?

Vestibular schwannomas (VSs) are the most common cerebellopontine tumors. The natural history of smaller-sized VSs (<30 mm) has been well-studied, leading to the recommendation of a "watch and wait" approach. However, large VSs (>30 mm) have not been extensively studied, mainly because of their rarity. As such, most patients are conventionally offered surgery which carries a significant risk of neurological morbidity. Here, we report a case of a giant VS (>40 mm) in a 30-year-old man who regressed spontaneously. He was lost to follow-up for 18 years and, upon re-presentation, the symptomatology drastically improved and repeat imaging demonstrated a marked reduction in tumor size. Referring to similar cases in other studies, we postulate that most large and giant VSs undergo a phase of growth and stasis, followed by regression due to shifts in the balance between tumorigenic and regressive factors. Taken together with emerging molecular data, further studies are required to better understand the history of large and giant VSs to shape more personalized treatment options. This potentially includes non-operative management as a tenable option.

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis.

PURPOSE: The most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT. METHODS: CT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann's area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored. RESULTS: The posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications. CONCLUSION: Preoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann's triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

Outcomes of Trigeminal Ganglion Sparing Surgical Resection of Nonacoustic Cerebellopontine Angle Tumors Causing Trigeminal Neuralgia.

OBJECTIVE: Tumors may be responsible for up to 5% of trigeminal neuralgia cases. Predictors of long-term pain relief after surgical resection of various cerebellopontine angle tumor types are not well understood. Previous studies found that size and extent of resection predict long-term pain status, although resection of tumor involving the trigeminal ganglion may be associated with high morbidity. This study evaluated predictors of TN pain freedom after resection of a nonacoustic CPA tumor, with avoidance of any portion involving the TG. METHODS: In a retrospective cohort study, we evaluated clinical outcomes and complications after surgical resection of nonacoustic CPA tumors with purposeful avoidance of the TG causing trigeminal neuralgia. The primary outcome was pain-freedom. We performed logistic regression analyses to examine the relationship between pain-freedom at last follow-up and age, side of symptoms, preoperative symptom duration, tumor diameter, tumor type, and concurrent neurovascular compression (NVC). RESULTS: Of 18 patients with nonacoustic CPA tumors causing TN treated with surgical resection, 83.3% were pain-free at last follow-up (mean 44.6 months). Age (P = 0.12), side (P = 0.41), preoperative symptom duration (P = 0.85), tumor diameter (P = 0.29), tumor type (P = 0.37), and NVC presence (P = 0.075) were not associated with long-term pain freedom. CONCLUSIONS: This study provides additional evidence that various tumor types causing TN may safely undergo surgical resection and decompression of the trigeminal nerve to treat TN. This study presents a cohort of patients that underwent resection of a nonacoustic CPA tumor, with purposeful avoidance of the TG to minimize complications, demonstrating high rates of long-term pain freedom.

Predictive value of Blink reflex and facial corticobulbar motor evoked potential in cerebellopontine angle tumor surgery.

OBJECTIVE: The current study examined the efficacy of the facial corticobulbar motor evoked potentials (FCoMEPs) and blink reflex (BR) on predicting postoperative facial nerve function during cerebellopontine angle (CPA) tumor surgery. METHODS: Data from 110 patients who underwent CPA tumor resection with intraoperative FCoMEPs and BR monitoring were retrospectively reviewed. The association between the amplitude reduction ratios of FCoMEPs and BR at the end of surgery and postoperative facial nerve function was determined. Subsequently, the optimal threshold of FCoMEPs and BR for predicting postoperative facial nerve dysfunction were determined by receiver operating characteristic curve analysis. RESULTS: Valid BR was record in 103 of 110 patients, whereas only 43 patients successfully recorded FCoMEP in orbicularis oculi muscle. A reduction over 50.3% in FCoMEP (O. oris) amplitude was identified as a predictor of postoperative facial nerve dysfunction (sensitivity, 77.1%; specificity, 83.6%). BR was another independent predictor of postoperative facial nerve deficit with excellent predictive performance, especially eyelid closure function. Its optimal cut-off value for predicting long-term postoperative eyelid closure dysfunction was was 51.0% (sensitivity, 94.4%; specificity, 94.4%). CONCLUSIONS: BR can compensate for the deficiencies of the FCoMEPs. The combination of BR and FCoMEPs can be used in CPA tumor surgery. SIGNIFICANCE: The study first proposed an optimal cut-off value of BR amplitude deterioration (50.0%) for predicting postoperative eyelid closure deficits in patients undergoing CPA tumor surgery.

Bevacizumab Treatment for Patients with NF2-Related Schwannomatosis: A Single Center Experience.

(1) Background: NF2-related schwannomatosis, characterized by the development of bilateral vestibular schwannomas, often necessitates varied treatment approaches. Bevacizumab, though widely utilized, demonstrates variable effectiveness on hearing and tumor growth. At the same time, (serious) adverse events have been frequently reported. (2) Methods: A single center retrospective study was conducted, on NF2-related schwannomatosis patients treated with bevacizumab from 2013 to 2023, with the aim to assess treatment-related and clinical outcomes. Outcomes of interest comprised hearing, radiologic response, symptoms, and adverse events. (3) Results: Seventeen patients received 7.5 mg/kg bevacizumab for 7.1 months. Following treatment, 40% of the patients experienced hearing improvement, 53%, stable hearing, and 7%, hearing loss. Vestibular schwannoma regression occurred in 31%, and 69% remained stable. Further symptomatic improvement was reported by 41%, stable symptoms by 47%, and worsened symptoms by 12%. Treatment discontinuation due to adverse events was observed in 29% of cases. Hypertension (82%) and fatigue (29%) were most frequently reported, with no occurrences of grade 4/5 toxicities. (4) Conclusion: Supporting previous studies, bevacizumab demonstrated positive effects on hearing, tumor control, and symptoms in NF2-related schwannomatosis, albeit with common adverse events. Therefore, careful consideration of an appropriate management strategy is warranted.

Multicompartmental cystic trigeminal schwannoma as an uncommon differential diagnosis of cerebellopontine angle tumors.

Trigeminal schwannoma is the second most common intracranial schwannoma yet accounts for less than 0.5% intracranial tumors [1]. Cystic degeneration is uncommon. We would like to report a pathologically proven multicompartmental cystic trigeminal schwannoma in a young adult presenting with chronic headache. A literature review on the imaging features of trigeminal schwannoma is performed to assist radiologists in accurate disease localization and prioritizing differential diagnosis in challenging cases. Confident preoperative radiological diagnosis would directly affect management strategies.

Intracranial malignant peripheral nerve sheath tumor: A case report and comprehensive literature review.

Background: Malignant peripheral nerve sheath tumors (MPNSTs) are rare malignant soft-tissue sarcomas arising from peripheral nerves. Little data exist regarding MPNST originating intracranially. Here, we present a 7th/8th nerve complex MPNST, discuss the treatment strategy and patient outcome, and provide a comprehensive review of existing literature. Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed and crossed references were queried, yielding 37 publications from 1952 to the present. Fifty-three cases of primary intracranial and extra-axial MPNST were identified. Results: We additionally report a 40-year-old female presented with acute onset dizziness and subsequent hearing loss with associated right-sided facial numbness. Magnetic resonance imaging revealed a 0.5 cm × 1.7 cm enhancing lesion within the right internal auditory canal extending into the cerebellopontine angle. The patient was initially treated with retro sigmoid craniotomy for tumor resection followed by a trans labyrinth approach for residual tumor resection. She completed adjuvant fractionated radiation therapy and underwent facial nerve transfer to restore complete hemifacial paralysis. The most common cranial nerves involved were V and VIII (43.4% each), with 66% of patients male and 34% female. The average age was 43.4 ± 17.4 years. The mean survival time for reported non-survivors after tissue diagnosis was 15 ± 4 months. Two-year survival for patients receiving gross total resection was 33.3% versus 22.8% with subtotal resection. Conclusion: MPNSTs comprise a group of highly aggressive neoplasms that rarely arise intracranially. Gross total surgical resection should be pursued when feasible.

Red flags alerting a posterior cranial fossa tumor from audiovestibular perspectives - a review.

BACKGROUND: There is no comprehensive and up-to-date overview of audiovestibular approach to the posterior fossa tumors in the literature. OBJECTIVE: This paper reviewed the literature relating to tumors at the posterior cranial fossa to find red flags alerting a posterior fossa lesion from audiovestibular perspectives. METHODS: This review was developed from articles published in those journals listed on the journal citation reports. Through the PubMed database, Embase, Google Scholar, and Cochrane library, 60 articles were finally obtained based on the PRISMA guidelines for reporting reviews. RESULTS: The presence of one red flag indicates a positive predictive value of 33% for detecting a posterior fossa lesion. Clinical features, namely, 1) mid-frequency sudden sensorineural hearing loss (SNHL), 2) bilateral sudden SNHL, and 3) rebound nystagmus may indicate a posterior fossa lesion, representing one, two, and three red flags, respectively. CONCLUSION: Those with 1) mid-frequency sudden SNHL, 2) bilateral sudden SNHL, and 3) rebound nystagmus trigger one, two, and three red flags, respectively, alerting clinicians the possibility of a posterior fossa lesion, which warrant MR imaging to exclude life-threatening or treatable conditions. SIGNIFICANCE: Patients with posterior fossa tumors may have potential life-threatening outcome.