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A schwannoma is a nerve sheath tumor that is formed by Schwann cells. Vestibular schwannomas are thought to account for the majority of intracranial schwannomas. Nonvestibular schwannomas account for about 10%, about half of which are trigeminal schwannomas. Multiple intracranial schwannomas originating from different cranial nerves are extremely rare. We describe the clinical case of a 42-year-old female patient with vestibular schwannoma and multiple trigeminal schwannomas. That case shows how multiple trigeminal schwannomas were identified intraoperatively during elective surgery for vestibular schwannoma removal, most of which were resected. No new neurological deficits were observed in the patient. The presence of multiple intracranial schwannomas is extremely rare in neurosurgical practice and can change the intraoperative strategy and the course of the surgery. [ABSTRACT FROM AUTHOR]

Radiation treatment, particularly at a young age, creates theoretical risk for long-term adverse radiation effects, including the development of malignancy. The literature is sparse on radiation-induced vestibular schwannomas (VSs). A retrospective review was performed for cases of suspected radiation-induced VS at 2 high-volume centers. Only cases where radiation included coverage of the posterior fossa were included with those diagnosed within 3 years of radiation treatment being excluded. Patient and tumor characteristics were collected. A systematic literature review was also performed for any previously published series on radiation-induced VS. Eight cases of radiation-induced VS were identified with a median follow-up 125 months (range 7–131). The median age at incident radiation was 15 years (range 2–46). The median age at VS diagnosis was 57 years (range 26–83) with median interval from radiation to diagnosis of 51-years (range 15–66). The median tumor size was 6 mm (range 3–21). Two patients underwent surgical resection. Lesions were described as soft and highly vascular, with medium to high adherence to the facial nerve. Five articles with a total of 52 patients were identified, median age at VS diagnosis was 42-years (range 23–73) with a median interval from radiation to diagnosis of 19 years (range 15–23). The development of VS following radiation exposure appears rare and our understanding of the condition remains incomplete. Further studies are required to determine the best management of these patients and determine whether there is a causative relationship between radiation exposure and the development of VS. [ABSTRACT FROM AUTHOR]

Schwannomas and meningiomas are the most common intradural extramedullary spinal tumors; however, differentiating between them using magnetic resonance imaging (MRI) is a frequent challenge. In this study, we aimed to investigate the use of the contrast ratio (CR) as a quantitative MRI method in the differentiation of schwannomas and meningiomas. We analyzed the data of patients with intradural extramedullary spinal tumors who underwent surgery and were diagnosed with either schwannomas or meningiomas by histopathological analysis. Regions of interest were set for the entire spinal tumor on T2-weighted sagittal MRI. To obtain the CR values of spinal tumors (CR tumor), we used the signal intensity (SI) values of the tumor (SI tumor) and spinal cord (SI cord) according to the following formula: [CR tumor = (SI tumor -SI cord)/(SI tumor +SI cord)]. The study included 50 patients (23 males and 27 females) with a mean age of 61.5 years old (11–85 years old). Histopathological analysis revealed that 33 and 17 patients were diagnosed with schwannomas and meningiomas, respectively. The mean CR values of the schwannomas and meningiomas were 0.3040 ± 0.1386 and 0.0173 ± 0.1929, respectively. The CR value of the schwannomas was statistically significantly higher than that of meningiomas (P < 0.01). The cutoff CR value obtained from the receiver operating characteristic curve was 0.143, with a specificity and sensitivity of 90.9% and 88.2%, respectively. Furthermore, the value for the area under the receiver operating characteristic curve was 0.925 (95% confidence interval: 0.852–0.998). The evaluation of CRs by using MRI to distinguish between schwannomas and meningiomas is a beneficial quantitative tool. [ABSTRACT FROM AUTHOR]

Vestibular schwannomas (VSs) are benign tumors often monitored over time, with measurement techniques for assessing growth rates subject to significant interobserver variability. Automatic segmentation of these tumors could provide a more reliable and efficient for tracking their progression, especially given the irregular shape and growth patterns of VS. Various studies and segmentation techniques employing different Convolutional Neural Network architectures and models, such as U-Net and convolutional-attention transformer segmentation, were analyzed. Models were evaluated based on their performance across diverse datasets, and challenges, including domain shift and data sharing, were scrutinized. Automatic segmentation methods offer a promising alternative to conventional measurement techniques, offering potential benefits in precision and efficiency. However, these methods are not without challenges, notably the "domain shift" that occurs when models trained on specific datasets underperform when applied to different datasets. Techniques such as domain adaptation, domain generalization, and data diversity were discussed as potential solutions. Accurate measurement of VS growth is a complex process, with volumetric analysis currently appearing more reliable than linear measurements. Automatic segmentation, despite its challenges, offers a promising avenue for future investigation. Robust well-generalized models could potentially improve the efficiency of tracking tumor growth, thereby augmenting clinical decision-making. Further work needs to be done to develop more robust models, address the domain shift, and enable secure data sharing for wider applicability. [ABSTRACT FROM AUTHOR]

Malignant soft tissue spinal canal tumors compromise 20% of all spinal neoplasms. They may be primary or metastatic lesions, originating from a diverse range of tissues within and surrounding the spinal canal. These masses can present as diverse emergencies such as secondary cauda equina syndrome, vascular compromise, or syringomyelia. Interpretation of malignant soft tissue spinal canal tumors imaging is an essential for non-radiologists in the setting of emergencies. This task is intricate due to a great radiologic pattern overlap among entities. We present a step-by-step strategy that can guide nonradiologists identify a likely malignant soft tissue lesion in the spinal canal based on imaging features, as well as a review of the radiologic features of malignant soft tissue spinal canal tumors. Diagnosis of soft tissue spinal canal malignancies starts with the identification of the lesion's spinal level and its relationship to the dura and medulla. The second step consists of characterizing it as likely-malignant based on radiological signs like a larger size, ill-defined margins, central necrosis, and/or increased vascularity. The third step is to identify additional imaging features such as intratumoral hemorrhage or cyst formation that can suggest specific malignancies. The physician can then formulate a differential diagnosis. The most encountered malignant soft tissue tumors of the spinal canal are anaplastic ependymomas, anaplastic astrocytomas, metastatic tumors, lymphoma, peripheral nerve sheath tumors, and central nervous system melanomas. A review of the imaging features of every type/subtype of lesion is presented in this work. Although magnetic resonance imaging remains the modality of choice for spinal tumor assessment, other techniques such as dynamic contrast agent-enhanced perfusion magnetic resonance imaging or diffusion-weighted imaging could guide diagnosis in specific situations. In this review, diagnostic strategies for several spinal cord tumors were presented, including anaplastic ependymoma, metastatic spinal cord tumors, anaplastic and malignant astrocytoma, lymphoma, malignant peripheral nerve sheath tumors , and primary central nervous system melanoma. Although the characterization of spinal cord tumors can be challenging, comprehensive knowledge of imaging features can help overcome these challenges and ensure optimal management of spinal canal lesions. [ABSTRACT FROM AUTHOR]

Schwannomas are benign peripheral nerve sheath tumors arising from myelinating Schwann cells. Although macrocystic changes are regularly encountered in schwannoma variants such as vestibular nerve tumors, they are exceedingly rare among spinal neoplasms. Case report and systematic review of 4 databases (Ovid Medline, PubMed, Science Direct, and SCOPUS) from inception to present. All peer-reviewed publications reporting intradural cystic thoracic schwannoma were included. We identified 8 publications documenting 9 cases of cystic thoracic schwannoma. Four were female, 5 male; median age was 41 years (range, 27–80). Presentations ranged from incidental to pain, sensory changes, lower extremity paresis, or bowel/bladder dysfunction. Characteristic radiographic findings included T1 hypointensity, T2 hyperintensity, and cord effacement or compression. The present case followed a similar pattern: a 52-year-old male presented with worsening bilateral lower extremity weakness, low back pain, and gait dysfunction, worsening over 3 days. Examination also revealed decreased left lower extremity sensation. Imaging identified a well-delineated intradural, extramedullary macrocystic extending over T7-T10. The patient underwent a laminectomy resulting in complete tumor resection and restoration of intact neurologic function. Final pathology confirmed benign cystic schwannoma. Macrocystic thoracic schwannomas are exceedingly rare and lack a comprehensive scheme for clinical classification of their natural history and pathogenesis. We report the 10th case of such a schwannoma, and the first associated systematic review. Although macrocystic thoracic schwannomas are not frequently encountered, accurate diagnosis and appropriate neurosurgical treatment is critical in these vulnerable patients, given the opportunity for excellent functional outcomes following neurosurgical treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Intramedullary schwannoma is a relatively rare tumor with only a few literature reports. This study was aimed to report the clinical characteristics of intramedullary schwannoma and discuss imaging findings and treatment strategies. The inclusion criterion was consecutive patients with intramedullary schwannomas who were surgically treated in our institution between 2017 and 2022. Data included clinical characteristics, radiologic features, surgical management, and prognosis. Clinical and follow-up details of all cases were collected and reviewed. This study included 3 male and 8 female patients. The mean age was 45 years (range 26–77 years). Cervical spine (4 cases, 36.4%), thoracic spine (4 cases, 36.4%), and lumbosacral spine (3 cases, 27.3%) involvement was found. Weakness, numbness and pain of limbs were the main symptoms at administration. Preoperative magnetic resonance imaging demonstrated lesion with spinal cord medullary invasion and well demarcated margins. The postoperative histologic examination showed benign lesions and confirmed the schwannoma. This article presented a series of 11 cases of intramedullary schwannoma with sharp margins and well-enhanced features. Prognosis and functional recovery were good after gross total resection. [ABSTRACT FROM AUTHOR]

This study aims to determine the prevalence of vestibular schwannoma (VS) among patients presenting with sudden hearing loss (SHL) and to characterize the clinical features of individuals diagnosed with both VS and SHL. We conducted an observational retrospective review at a tertiary referral center, spanning a 30-year period, focusing on patients diagnosed with SHL where VS was confirmed as the underlying cause. We included patients meeting these criteria while excluding those lacking imaging or with a pre-existing diagnosis of VS. We evaluated the audiological characteristics at the time of diagnosis and assessed clinical outcomes following treatment. Among the 403 patients presenting with SHL during the study period, 9 (2.2%) were diagnosed with VS, aged between 25 and 72 years. Although audiometric profiles varied, high-frequency hearing loss predominated, mostly categorized as mild to moderate. Six patients (66%) had Koos grade I-II schwannomas. Only 2 patients achieved complete hearing recovery post-treatment, while 4 showed no improvement. VS is a rare etiology of SHL, accounting for slightly over 2% of cases. Its symptomatology, severity, and audiometric patterns do not significantly differ from SHL caused by other factors. Tumor size does not correlate with hearing characteristics. Treatment modalities resemble those for other SHL cases, and hearing improvement does not obviate the necessity for follow-up magnetic resonance imaging (MRI) scans. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) and recently, hypofractionated radiosurgery (hSRS) are increasingly utilized as treatment for vestibular schwannomas (VS). We performed a meta-analysis of literature comparing these modalities. The PubMed database of articles was searched for studies that compared SRS and hSRS in patients with VS. Variables analyzed include tumor control, hearing preservation, facial nerve preservation, trigeminal nerve preservation, and total complications. Heterogeneity across the studies was gauged using Higgins's inconsistency index. Funnel plots and Egger's regression intercept test were used to address the publication bias. Thirteen studies that satisfied the search criteria were selected for meta-analysis. The studies identified in our study included 353 SRS and 511 hSRS-treated patients. Analysis of heterogeneity showed that hSRS is employed for relatively larger tumor sizes in comparison to SRS. Pooled meta-analysis estimates showed no significant differences between SRS and hSRS in terms of tumor control (odds ratio [OR], 0.620; 95% confidence interval [CI], 0.21–1.86, P = 0.39), hearing preservation (OR, 1.07; 95% CI, 0.59–1.93, P = 0.83), facial nerve preservation (OR, 0.53; 5% CI, 0.23–1.21, P = 0.13), or trigeminal nerve preservation (OR, 0.67; 95% CI, 0.24–1.89, P = 0.49) at a mean follow-up of 39 months. Statistically significant heterogeneity was found across the studies only for tumor diameter (Higgins's inconsistency index = 65.69%, P = 0.003) but not for other variables. Meta-analysis of thirteen studies comparing SRS and hSRS as treatment for VS showed comparable tumor control, hearing preservation, facial nerve preservation, and trigeminal nerve preservation. [ABSTRACT FROM AUTHOR]

The coexistence of perisellar tumors and intracranial aneurysms was previously considered a rare phenomenon. In this study, we introduce our experience with surgical strategies for the treatment of such coexisting pathologies. This retrospective study reviews the medical records and intraoperative videos of patients with coexisting pathologies of perisellar tumors and aneurysms from Nov 2017 to Oct 2022. Our study involved 20 patients, including 9 males and 11 females. Three patients selected the single-stage endoscopic endonasal approach (EEA), including one with a type of MP trigeminal schwannoma with an anterior communicating aneurysm, 1 with a pleomorphic xanthoastrocytoma with a left internal carotid artery paraclinoid aneurysm, and 1 with a recurrent pituitary adenoma with a right internal carotid artery paraclinoid aneurysm. Thirteen patients chose tumor resection first through the EEA with embolization or aneurysm conservation. There were also 2 patients with irregularly shaped aneurysms who chose embolization before tumor resection. All tumors were completely removed, with only a few patients experiencing recurrence and postoperative complications, and the follow-up of the aneurysms was also stable. There were also 2 patients who chose conservative management for both tumors and aneurysms, but unfortunately, one of them suffered from aneurysm rupture and eventually died. No cerebrospinal fluid rhinorrhea, severe intracranial infection, or surgical-related hemorrhage was found in any patients. Staged surgery or conservative treatment for aneurysms can be considered a safe and effective strategy for the treatment of coexisting pathologies. However, in very selected cases, the single-stage EEA can be used as part of a comprehensive treatment for such coexisting pathologies. [ABSTRACT FROM AUTHOR]

Sacral masses can be removed using anterior, posterior, or combined approaches. Achieving total sacrectomy through a posterior-only approach results in a shorter procedure time, minimal tissue damage, and a reduced risk of complications. In this study, we aimed to share our experience with performing total sacrectomy using a posterior-only approach in 26 patients and to assess their clinical outcomes at our center. This retrospective study examines the clinical progression, surgical response, and outcomes of 26 patients with various sacral mass pathologies. We accessed patient information from our hospital records. The study included 14 men (54%) and 12 women (46%), with an average age of 49.8 years. Most cases had a normal body mass index, while 6 were overweight. Sacrectomy was performed at a high level in 12 patients and at a middle level in 14 patients. In addition to pain, motor deficits were observed in 9 patients, and sphincter dysfunction was found in 5. Preoperative embolization was conducted for 11 patients. The most prevalent lesions were chordoma (8 patients), malignant peripheral nerve sheath tumor (4 patients), giant cell tumor (3 patients), and solitary plasmacytoma (3 patients). Only 1 patient experienced a temporary partial motor deficit after surgery. There were no instances of cerebrospinal fluid leakage. Five patients experienced local recurrence, and 1 had distant metastasis. Performing sacrectomy for large or giant sacral tumors through a posterior approach is both feasible and safe, resulting in reduced morbidity and no significant change in overall survival. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration. Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990–2020 and had pre- and post-treatment audiograms. Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12–60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS. Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing. [ABSTRACT FROM AUTHOR]

Meckel cave tumors are relatively rare, especially trigeminal nerve (TN) schwannomas. These tumors frequently project through the trigeminal pore, occupying the middle and posterior fossae. The most used routes to this region are the suboccipital retrosigmoid intradural approach (SORSA) and the transzygomatic middle fossa approach (TZMFA). Both approaches allow further exposure by adding intraoperative techniques, such as removing the suprameatal tubercle (retrosigmoid intradural suprameatal approach [RISA]) and the petrous apex (TZMFA-PA), respectively. This study aims to understand how TN exposure differs between both surgical approaches and how it increases by adding specific surgical maneuvers to these techniques. Five formalin-fixed adult cadaver heads were submitted to high-resolution computed tomography and their images were loaded into the neuronavigation device. Anatomic key points were defined along the outline of the TN, and their three-dimensional spatial locations were collected following each surgical approach. This process allowed the calculation of the TN exposed area obtained through each technique. The mean areas of exposure of the TN were 125.9 mm2 with SORSA and 208.9 mm2 with RISA, which represents an additional mean gain of 61.92% (P = 0.047). Using TZMFA, a mean exposure of 419.24 mm2 was obtained. When TZMFA-PA was used, the mean exposed area was 486.03 mm2, representing a mean gain in the exposure area of 16.81% (P = 0.072). Our study suggests that TZMFA allows better exposure of TN ganglionic and postganglionic segments, and the removal of the PA adds the preganglionic segment visualization, although with less TN exposed area compared with RISA. With SORSA, the additional suprameatal tubercle removal shows the trigeminal pore and the medial margin of the central portion of the TN ganglionic segment, making it possible to expose the mouth of the Meckel cave and part of its contents. [ABSTRACT FROM AUTHOR]

To compare the impact of different management strategies on diagnosis of new-onset mental health disorders (MHDs) in patients with vestibular schwannoma (VS) and health care utilization at 1-year follow-up. MarketScan databases were queried using the International Classification of Diseases, Ninth Revision and Tenth Revision and Current Procedural Terminology, Fourth Edition, 2000–2020. We included patients ≥18 years old with a diagnosis of VS who underwent clinical observation, surgery, or stereotactic radiosurgery (SRS) with at least 1 year of follow-up. We looked at health care outcomes and MHDs at 3-month, 6-month, and 1-year follow-up. The database search identified 23,376 patients. Of these, 94.2% (n = 22,041) were managed conservatively with clinical observation at the initial diagnosis, and 2% (n = 466) underwent surgery. The surgery cohort had the highest incidence of new-onset MHDs followed by SRS and clinical observation cohorts at 3 months (surgery: 17%; SRS: 12%; clinical observation: 7%), 6 months (surgery: 20%; SRS: 16%; clinical observation: 10%), and 12 months (surgery: 27%; SRS: 23%; clinical observation: 16%) (P < 0.0001). The median difference in combined payments between patients with and without MHDs was highest in the surgery cohort followed by SRS and clinical observation cohorts at all time points (12 months: surgery: $14,469; SRS: $10,557; clinical observation: $6439; P = 0.0002). Compared with clinical observation only, patients who underwent surgery for VS were 2 times more likely and patients who underwent SRS were 1.5 times more likely to develop MHDs with corresponding increase in health care utilization at 1-year follow-up. [ABSTRACT FROM AUTHOR]

Management of large vestibular schwannoma (VS) is controversial. Surgery has historically been the treatment of choice, but emerging literature suggests that definitive stereotactic radiosurgery is feasible. We report our institutional experience of control and morbidity outcomes treating Koos grade 3–4 VS with Gamma Knife radiosurgery (GKRS). An institutional review board–approved database compiled outcomes of Koos grade 3–4 VS treated by GKRS from March 2014 to January 2021 with >6 months' follow-up. Baseline symptoms per Common Terminology Criteria for Adverse Events definitions were recorded. Control rates, toxicities, and post-treatment volumetric changes were analyzed. Aggregate impairment scores (AIs) were defined by the sum of relevant Common Terminology Criteria for Adverse Events grades to categorize symptomatic burdens. Baseline and post-treatment AIs were tested for association with definitive versus adjuvant strategies. In total, 34 patients with Koos grade 3–4 VS were identified, 19 treated with definitive GKRS (GKRS-D) and 15 with adjuvant GKRS (GKRS-A). Median follow-up was 34.2 months for GKRS-D and 48.8 months for GKRS-A. Patients who received GKRS-A had greater AIs at presentation (3.73 vs. 2.11, P = 0.017). Irrespective of treatment approach, tumor control rates were 100% without instances of brainstem necrosis or shunt placement. Six of 19 patients who received GKRS-D had improved post-treatment AI, and 63% of patients who received GKRS-D and 66% of patients who received GKRS-A had tumor shrinkage >20%. In well-selected patients with Koos grade 3–4 VS, definitive stereotactic radiosurgery may be an appropriate strategy with excellent control and minimal toxicity. Our data suggest that the need for surgical decompression should be considered based on pretreatment symptom burden rather than tumor size. [ABSTRACT FROM AUTHOR]

The far lateral approach provides wide surgical access to the lower third of the clivus, pontomedullary junction, and anterolateral foramen magnum and rarely requires craniovertebral fusion. The most common indications for this approach are posterior inferior cerebellar artery and vertebral arteryaneurysms, brainstem cavernous malformations, and tumors anterior to the lower pons and medulla, including meningiomas of the anterior foramen magnum, schwannomas of the lower cranial nerves, and intramedullary tumors at the craniocervical junction. We provide a stepwise description of how we perform the far lateral approach, as well as how to combine the far lateral approach with other skull base approaches, including the subtemporal transtentorial approach, for lesions involving the upper clivus; the posterior transpetrosal approach, for lesions involving the cerebellopontine angle and/or petroclival region; and/or lateral cervical approaches, for lesions involving the jugular foramen or carotid sheath regions. [ABSTRACT FROM AUTHOR]

This study was conducted with the aim to estimate long-term tumor control and hearing preservation rates in patients with neurofibromatosis 2 (NF2)-related vestibular schwannoma (VS), document retreatment success rate, and assess the associated predictive factors. This was a retrospective analysis of patients with NF2-associated VS who underwent Gamma Knife radiosurgery (GKRS) between 2009 and 2020 and had a minimum follow-up of 1 year. Loss of tumor control was defined as greater than 10% increase in volume in more than one follow-up imaging or the need for retreatment in the form of repeat GKRS or surgery. The Kaplan–Meier method was used to evaluate actuarial tumor control and hearing preservation rates. In total, 85 patients with 133 VSs were included in the study. The mean age was 29.8 years. In total, 57 tumors showed tumor regression, 35 showed stable disease, and 23 progressed in size at last follow up. Actuarial tumor control rates after 1, 3, 5, and 9 years were 95%, 79%, 75%, and 55%, respectively, with overall tumor control rate being 85%. Hearing worsened in 39 patients, and facial nerve dysfunction occurred in 4 patients. Five tumors underwent retreatment with GKRS at a median duration of 27.6 months (19–36 months) following the first GKRS. This is the largest radiosurgical series of NF2-associated VS reported to date. GKRS provides a high rate of long-term local tumor control with a low risk of neurologic deprivation for patients with these tumors. The need for retreatment with GKRS, although low, is associated with good tumor control and lesser complications. [ABSTRACT FROM AUTHOR]

Trigeminal schwannoma is an uncommon tumor in pediatric patients. Several surgical approaches have been described in the literature. The case of an 11-year-old boy with a giant dumbbell-shaped trigeminal schwannoma removed through a 2-stage approach was presented with an intraoperative video. Using PubMed and Scopus, the literature on trigeminal schwannoma in pediatric patients was searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The search strategy yielded 312 titles, of which 13 were included in the review. Cases of trigeminal schwannoma were described, with a highly variable clinical presentation and anatomical arrangement in cranial fossae. Two-stage approaches were reported, although most studies described single-stage approaches. Common postoperative outcomes were a range of disturbances of cranial nerve V. The surgical approach varies based on the tumor conformation. However, a 2-stage pterional subtemporal and semisitting retrosigmoid approach is a safe, practical, and effective strategy for the removal of dumbbell-shaped trigeminal schwannoma in a pediatric patient. [ABSTRACT FROM AUTHOR]

Carotid sympathetic plexus (CSP) schwannomas are rare brain tumors located in a complex site around the cavernous sinus and carotid canal in the petrous bone. This study describes 3 cases of CSP schwannomas that underwent surgical removal of the tumor through an endoscopic endonasal transpterygoid approach. Between 2016 and 2021, 3 cases of CSP schwannomas were treated using an endoscopic endonasal transpterygoid approach. Preoperative tumor size, preoperative and postoperative symptoms, internal carotid artery (ICA) displacement, extent of tumor resection, intraoperative findings showing tumor origin, and surgical complications were evaluated in all patients. Two tumors were in the petrous region, and the other one was in both the petrous and cavernous regions. The median tumor diameter was 41.3 mm. In the 3 cases, the ICA was displaced to the superolateral side, the anterolateral side, and the posterior side, respectively. Near-total resection was achieved in all 3 cases via an endoscopic endonasal transpterygoid approach. There were no endonasal postoperative complications, and the cranial nerve disability improved in all 3 patients at 1-year follow-up. The surgical technique for CPS schwannoma using an endoscopic endonasal transpterygoid approach may be a viable option because endoscopy has been proven to offer better intraoperative visualization and reduce postoperative discomfort for patients. Tumors located medial and inferior to the ICA pars cavernous sinus or anterior, inferior, and medial to the paraclival ICA are ideal candidates for surgery using this endoscopic approach. [ABSTRACT FROM AUTHOR]

Dumbbell-shaped schwannomas are slow-growing tumors that are typically benign lesions. They account for 6%–14% of spinal neoplasms, with 30% having intradural and extradural components. 1 A schwannoma is considered "giant" if it extends beyond the spine by >2.5 cm and involves more than 2 vertebral levels. 2 The Eden classification categorizes these tumors into 4 types on the basis of the primary component. 3 Surgery is recommended for individuals experiencing prolonged nerve damage and persistent neurogenic pain that cannot be managed. 2 There are 3 surgical options for managing thoracic dumbbell schwannomas 4 : the single-stage posterior-only approach, 5 the single-stage anterior-only approach, 6 and the single-stage combined posteroanterior neurosurgical and video-assisted thoracoscopic approach. The latter option allows for the most comprehensive lesion control including vascular and nerve structures and optimal hemostasis control. It also avoids spinal instrumentation and provides certainty for complete tumor removal. 7 Video 1 shows a surgical procedure performed on a 58-year-old woman to remove a thoracic dumbbell neurinoma. The patient consented to the procedure and publication of her image. A simultaneous thoracoscopic and neurosurgical approach was performed. The surgical team successfully removed the schwannoma, and the patient's recovery was smooth, with no neurologic issues or pain. This case highlights the benefits of using a single-stage combined approach for treating Eden II and Eden III giant dumbbell thoracic schwannomas. [ABSTRACT FROM AUTHOR]

Facial nerve (FN) schwannomas are extremely rare. According to their origin and involved segment(s), they constitute distinct subtypes. Intact FN function presents a management challenge, particularly in the cerebellopontine angle cisternal subtype that masquerades as a vestibular schwannoma. Fascicular-sparing technique with subtotal resection can maintain a good FN function. This study focuses on management to maintain good FN function. A retrospective analysis of a cohort of 13 patients harboring FN schwannoma. Patient demographics, clinical findings, imaging, surgical intervention, and outcomes were analyzed. Five women and 8 men, with an average age of 55.3 years (39–75 years), harbored 6 cisternal, 2 ganglion, and 5 combined tumors. Average tumor size was 28.3 mm (16–50 mm). Eleven patients underwent surgery. Seven patients had fascicle-sparing technique, 5 of whom maintained their preoperative FN function, whereas 2 patients with near-total removal had a deterioration in FN function. Two patients with preoperative complete facial paralysis had gross total removal with interposition nerve graft. FN schwannomas management is individualized according to the subtype and the FN function at presentation. When FN function is normal, observation can be applied for prolonged period of time. At the early sign of deterioration, sub- or near-total resection with fascicle sparing technique can be performed. The cisternal subtype masquerade as vestibular schwannoma and should be recognized at the initial exposure by the appearance of finely splayed nerve fascicles at the perimetry of the tumor which elicits a motor response at low threshold stimulation. [ABSTRACT FROM AUTHOR]

Spinal schwannomas (SSs) are usually benign tumors with a good prognosis when treated by surgical excision. However, complete resection can be complicated by factors such as the tumor location and configuration. In the present study, we sought to identify the factors associated with incomplete surgical resection (residual) and the factors associated with tumor recurrence. We performed a retrospective review of 113 cases of SSs treated surgically from 2008 to 2021. Of the 113 SSs, 102 were benign and 2 were malignant nerve sheath tumors. Of the 102 benign SSs, gross total resection (GTR) was performed for 87, with 8 displaying residual and 7, recurrent tumor. We found a significantly higher ratio of cervical and sacral tumors (P = 0.008 and P = 0.004, respectively), dumbbell and foraminal configurations (P < 0.0001 and P = 0.0006, respectively), and larger tumor volumes (P = 0.003) in the residual and recurrent cohorts compared with the GTR cohort. A second operation was performed for 2 patients in the residual and 4 patients in the recurrent cohorts. The total complication rate was 6%. We found that most benign SSs will be amenable to GTR (85% of cases), with an excellent prognosis. The patients with residual or recurrent tumor were more likely to have had a cervical or sacral location, a dumbbell or foraminal configuration, and a larger tumor volume. Except for 1 new SS and 1 recurrent tumor that had necessitated a lateral approach, the remainder had been treated using a posterior approach. At surgery, ultrasonography of the canal is advisable to ensure that the intra- and extraspinal components of dumbbell lesions have both been entirely removed. [ABSTRACT FROM AUTHOR]

The effectiveness of gamma knife radiosurgery (GKRS) for the management of trigeminal schwannomas (TS) has been established. Although GKRS has been shown to inhibit tumor growth, the effect of GKRS on the symptoms caused by TS has not been sufficiently studied. In this study, symptomatic changes following GKRS for the management of symptomatic TS were investigated using long-term follow-up results. A retrospective analysis was performed on 32 patients with TS who underwent GKRS between May 1994 and December 2016. Clinical charts, radiographic results, and surgical records were reviewed. To evaluate whether symptoms improved after GKRS, patient demographics, GKRS profile, radiological tumor size change, and tumor location were analyzed. Tumor control after GKRS for symptomatic TS was 87%. The improvement rates for facial pain at 6, 12, and 24 months after GKRS were 46%, 72%, and 86%, respectively. For the same time intervals, facial hypesthesia improved by 12%, 46%, and 52%, respectively. Of the patients with diplopia, 17% had improved symptoms 12 months after GKRS, and 50% of the patients improved after 24 months. GKRS can be an effective treatment modality for TS tumor control and shows favorable results in improving TS-related symptom, especially facial pain. [ABSTRACT FROM AUTHOR]

Primary tumors involving the spine are relatively rare but represent surgically challenging procedures with high patient morbidity. En bloc resection of these tumors necessitates large exposures, wide tumor margins, and poses risks to functionally relevant anatomical structures. Augmented reality neuronavigation (ARNV) represents a paradigm shift in neuronavigation, allowing on-demand visualization of 3D navigation data in real-time directly in line with the operative field. Here, we describe the first application of ARNV to perform distal sacrococcygectomies for the en bloc removal of sacral and retrorectal lesions involving the coccyx in 2 patients, as well as a thoracic 9–11 laminectomy with costotransversectomy for en bloc removal of a schwannoma in a third patient. In our experience, ARNV allowed our teams to minimize the length of the incision, reduce the extent of bony resection, and enhanced visualization of critical adjacent anatomy. All tumors were resected en bloc, and the patients recovered well postoperatively, with no known complications. Pathologic analysis confirmed the en bloc removal of these lesions with negative margins. We conclude that ARNV is an effective strategy for the precise, en bloc removal of spinal lesions including both sacrococcygeal tumors involving the retrorectal space and thoracic schwannomas. [ABSTRACT FROM AUTHOR]

Radical resection of complex lesions occupying multiple compartments at the central skull base remains a significant challenge, since surgical outcomes may be compromised by insufficient exposure and inappropriate techniques. However, the efficiency of the maxillary swing approach for these lesions has not been sufficiently evaluated. Careful assessment of lesion characteristics must be performed when selecting the appropriate procedure. Between May 2006 and February 2017, 17 patients underwent resection of extensive lesions in the central skull base using the maxillary swing approach. As shown in the representative cases, data regarding clinical findings and technical considerations were reviewed. Complete resection was achieved in all patients. The pathological findings were diverse, and the majority were schwannomas (9 cases, 52.94%), followed by meningiomas (World Health Organization II) (3 cases, 17.65%). Complications were managed as described in the case illustrations, and symptoms improved with time. The follow-up duration ranged from 62 to 192 months (median, 114 months), while 2 patients were lost to the follow-up. No mortality was observed. Two patients who experienced malignancy relapse were still under observation due to their asymptomatic status. Our preliminary results suggest that the maxillary swing approach can be an alternative option for managing extreme cases, such as large, extensive, hypervascularized masses with fibrous or calcified consistency, or for recurrent lesions in the central skull base. En bloc resection can be successfully obtained, resulting in long-term local control. [ABSTRACT FROM AUTHOR]

This study aimed to identify the risk factors for acute obstructive hydrocephalus (AOHCP) after extra-axial cerebellopontine angle (CPA) tumor surgery using the retrosigmoid (RS) approach. This retrospective study assessed 154 patients (100 vestibular schwannomas, 34 CPA meningiomas [MNGs], 9 trigeminal schwannomas, and 11 petroclival MNGs) who underwent surgical resection using the RS approach by a single surgeon between August 2010 and September 2019. AOHCP was defined as postoperative ventricular enlargement due to cerebrospinal fluid flow obstruction caused by surgery-related cerebellar injury within 1 week. The radiological characteristics of the tumors were classified, and the surgical outcomes were reviewed. We analyzed the impact of different factors on the development of AOHCP after surgery. AOHCP developed in 17 (11%) patients, all of whom were treated with external ventricular drain insertion. Multivariate analysis showed that CPA MNGs (odds ratio [OR], 37.98), grade of tumor extension beyond the petroclival junction (grade 1: OR, 16.42; grade 2: OR, 17.47), major fourth ventricle compression (OR, 17.77), and surgery-related hemorrhage (OR, 7.64) were associated with AOHCP. Surgery-related hemorrhage was observed in 17 (11%) patients. 9 (6%) patients underwent ventriculoperitoneal shunt surgery because of persistent HCP. An increased risk of AOHCP after the RS approach was observed in patients with extra-axial CPA tumors with clival extension and major fourth ventricle compression. Compulsive and meticulous hemostasis must be achieved because postoperative hemorrhage is associated with AOHCP. [ABSTRACT FROM AUTHOR]

The incidence of dural venous sinus thrombosis (DVST) following vestibular schwannoma (VS) surgery remains understudied. The diverse clinical presentation complicates forming anticoagulation treatment guidelines. This meta-analysis aimed to investigate the incidence of DVST post-VS surgery and to evaluate the role of anticoagulation. A systematic review, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, was conducted. Studies reporting DVST incidence after VS surgery were included. DVST incidence stratified by detection method was the primary outcome. Adverse events per treatment strategy (anticoagulation or no anticoagulation) were the secondary outcome. Pooled incidence with respective 95% confidence intervals were calculated using the random-effects model via the DerSimonian and Laird method. The overall DVST incidence post-VS resection was 15.5% (95% confidence interval: 10.3%, 22.5%; 10 studies). Stratification by detection method revealed 29.4% (19.2%, 42.3%) for magnetic resonance imaging, 8.2% (3.2%, 19.5%) for computed tomography, and 0.7% (0.2%, 2.8%) upon clinical suspicion. The pooled incidence of adverse events was 16.1% (6.4%, 35.0%) for the anticoagulation treatment and 4.4% (1.4%, 12.9%) for no anticoagulation treatment, with one mortality case being among the adverse events in this latter group. DVST after VS surgery is more common than initially perceived, predominantly presenting asymptomatically. Variability in anticoagulation protocols hinders the establishment of definitive therapeutic stances; nevertheless, there is no supporting evidence to promote anticoagulation administration for DVST. This begs the need for further institutional comparative studies with a proper adjustment for confounding and well-defined anticoagulation regimens. [ABSTRACT FROM AUTHOR]

Vestibular schwannomas are benign, slow-growing tumors that often reduce patient quality of life by compressing nearby nerves. Neurological function preservation is one of the indicators of treatment success, with hearing preservation being the most difficult to obtain. This paper provides a bibliometric analysis of hearing preservation in treating acoustic neuromas and a greater understanding of the most highly cited articles, which have enhanced our understanding of this topic. Key terms of "acoustic neuroma," "vestibular schwannoma," and "hearing preservation" were queried through Web of Science. Articles were sorted by citation frequency, and the top 100 articles were recorded for title, name of first author, journal title, year of publication, total number of citations (and associated rank), average number of citations per year, country of the first author's associated institution, and type of study. The top 100 cited articles were published from 1980 to 2014. The United States had the highest involvement as a country (55%), the University of Pittsburgh as an institution (13%), and The Journal of Neurosurgery as a publishing source (27%). Fourteen were reviews, and 86 were clinical papers. Of the 86, 73 were retrospective studies. Bibliometric analyses summarize and assess potential areas of strength and knowledge gaps within the literature. Studies on hearing preservation in vestibular schwannomas mostly consist of retrospective reviews that assess postoperative outcomes of microsurgery and radiosurgery. Prospective studies and novel treatment options for hearing preservation in vestibular schwannomas are needed to increase current literature diversity. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the risk of communicating hydrocephalus in cerebellopontine angle tumors, focusing on distinct tumor types and treatment modalities, i.e., tumor resection and stereotactic radiosurgery (SRS). This study was a retrospective single-center cohort study. The cumulative incidences of symptomatic communicating hydrocephalus in schwannoma and meningioma patients were evaluated. A multivariate Cox model was used to assess the hazard ratios for the risk factors and odds ratios of distinct treatment subgroups. A total of 405 cases, including 286 schwannomas and 119 meningiomas, were retrospectively reviewed. The risk of hydrocephalus was significantly higher in schwannomas than that in meningiomas (hazard ratio, 4.70 [95% confidence interval, 1.78–12.4, P = 0.002]). Patients with schwannomas who received SRS without tumor resection showed a significantly higher incidence than meningioma cases: 10.6% versus 1.4% (P = 0.037). We identified specific subgroups that were prone to increase the risk of hydrocephalus when treated with SRS alone. The result showed that patients with vestibular schwannoma of Koos grade III had a greater benefit from tumor resection than from SRS in preventing hydrocephalus (odds ratio, 0.089 [95% confidence interval, 0.011–0.743, P = 0.025]). Symptomatic communicating hydrocephalus is more frequent in schwannoma than that in meningiomas. Primary treatment with tumor resection lowers the risk of hydrocephalus in specific subgroups of vestibular schwannoma. [ABSTRACT FROM AUTHOR]

Data on the outcomes of CyberKnife-based hypofractionated stereotactic radiosurgery (hSRS) for intracranial and extracranial nonvestibular schwannomas (nVSs) are not sufficient. Patients who underwent hSRS for nVSs between 2010 and 2019 were retrospectively reviewed. A total of 39 patients with 39 nVSs were identified. The mean age was 53 (±18) years, and 20 patients (51%) were women. Twenty-five patients (64%) had previous surgeries. Seventeen patients (44%) had nVSs extending outside the cranium. The mean prescribed dose covering 95% of the planning target volume was 22 Gy (±3.7 Gy), the mean fractionation was 4 (±2), and the mean target volume was 13 cm3 (±16 cm3). The radiological tumor control rate was 100% during the mean follow-up period of 67 months (±37 months). Thirty-seven patients (95%) were clinically stable during the mean follow-up period of 72 months (±35 months). Nine patients (23%) suffered from transient adverse radiation effects (AREs), including transient tumor expansion, and 2 (5%) suffered from permanent AREs. We summarized the treatment outcomes of hSRS for nVSs. Although all patients achieved radiological tumor control, the risk of either transient or permanent ARE was high. Therefore, it is necessary to monitor patients for clinical deterioration due to AREs. [ABSTRACT FROM AUTHOR]

Benign tumors that grow in the spinal canal are heterogeneous neoplasms with low incidence; from these, meningiomas and nerve sheath tumors (neurofibromas and schwannomas) account for 60%–70% of all primary spinal tumors. Benign spinal canal tumors provoke nonspecific clinical manifestations, mostly related to the affected level of the spinal cord. These tumors present a challenge for the patient and healthcare professionals, for they are often difficult to diagnose and the high frequency of posttreatment complications. In this review, we describe the epidemiology, risk factors, clinical features, diagnosis, histopathology, molecular biology, and treatment of extramedullary benign meningiomas, osteoid osteomas, osteoblastomas, aneurysmal bone cysts, osteochondromas, neurofibromas, giant cell tumors of the bone, eosinophilic granulomas, hemangiomas, lipomas, and schwannomas located in the spine, as well as possible future targets that could lead to an improvement in their management. [ABSTRACT FROM AUTHOR]

Patients with malignant peripheral nerve sheath tumors (MPNSTs) of major motor nerves typically present with muscle weakness and pain. We aimed to analyze and characterize patients with MPNSTs of major motor nerves but without muscle weakness at initial presentation. We performed a retrospective search of MPNSTs in a major nerve evaluated and/or treated at our institution from 1994 to 2019. Patients with no muscle weakness and available magnetic resonance imaging were analyzed. Clinical materials and magnetic resonance imaging and positron emission tomography scans were reviewed for features of malignancy. This group of patients was compared with patients who presented with MPNSTs and muscle weakness. Of 26 patients with MPNSTs who presented with no muscle weakness, 21 (81%) had a positive family history for malignancy. Only 16 (62%) magnetic resonance imaging scans were highly suspicious for malignancy. All 7 available positron emission tomography scans were highly suspicious for malignancy. Patients who presented with muscle weakness (n = 36) were more likely to have paresthesias and a history of neurofibromatosis 1 or radiation to the MPNST location (P < 0.05). MPNSTs of major motor nerves without muscle weakness represent an underappreciated subset of cases that have potential treatment and outcome implications. These patients presented with fewer symptoms and had fewer risk factors than patients with muscle weakness. Positron emission tomography should be considered as an additional method to try to anticipate the diagnosis of an MPNST. [ABSTRACT FROM AUTHOR]

Postoperative headache (POH) is a disturbing symptom following vestibular schwannoma (VS) resection. However, there are currently no treatment guidelines. The aim of this study was to evaluate the usefulness of symptom-based opioid-free treatments for persistent POH following VS resection. Of 137 patients in whom sporadic VS was resected via the retrosigmoid approach, 74 had persistent POH beyond 3 postoperative months. Their symptoms were classified as tension-type headache, migraine, neuralgia, or other and were treated. We retrospectively analyzed the treatment outcomes during 2 postoperative years. Patients with persistent POH were significantly younger (P = 0.003) and had significantly smaller tumors (P = 0.001) and greater extent of resection (P = 0.04) than patients without POH. The most common simple symptom was tension-type headache in 56 patients, followed by migraine in 6 patients and neuralgia in 5 patients. All 7 patients with complex symptoms had a mixture of tension-type headache and migraine. Complete disappearance of POH was achieved in 40 (54%) patients, and a medication-free condition was achieved in 51 (69%). No patients had residual severe POH that could not be controlled with medication. Achievement of a medication-free outcome that included complete disappearance of persistent POH was significantly more common in patients with preserved facial nerve function (P = 0.008) and patients with simple symptoms (P < 0.001). A symptom-based approach is appropriate for understanding and managing persistent POH after VS resection with excellent pain control. Preserved facial nerve function and simple symptoms are significant prognostic factors for a medication-free outcome. [Display omitted] [ABSTRACT FROM AUTHOR]

Cranial nerve schwannomas almost always arise from sensory or mixed nerves. Motor cranial nerves, such as the trochlear nerve, are rarely associated with schwannomas. No consensus has yet been made for surgical intervention because of the low number of reported cases of trochlear nerve schwannomas. This study comprises a systematic review of the literature and our experience for surgically treated trochlear nerve schwannomas. Three databases (Web of Science, PubMed, and Cochrane Library) were searched without date restrictions. Studies were included if they were published in the English literature and presented patients of any age who underwent surgical treatment for trochlear schwannoma. Data extracted from the included studies were combined with our experience. Forty-one studies, presenting 43 patients, met the inclusion criteria. The total number of patients was 45 after our experience was added. The most common symptoms were diplopia (62.2%), headache (46.7%), and motor weakness (37.8%). Mean age during the diagnosis was 45.1 years. Although the subtemporal transtentorial approach (n = 14) is the most preferred method, its application has decreased in recent years. In the last decade, the lateral suboccipital approach (n = 11) has gained popularity. Residual postoperative trochlear nerve deficit was detected in 81% of patients. The probability of neurologic deficit was not statistically associated with tumor volume (P = 0.914), location (P = 0.669), or resection rate (P = 0.554). Although trochlear schwannomas are rare and their treatment involves challenges, total resection with the proper approach provides the most desirable results. [ABSTRACT FROM AUTHOR]

Malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive soft tissue sarcomas of mesenchymal origin, characterized by a heterogeneous pathological spectrum, limited therapeutic options, and high metastatic potential. Here, the authors conducted a comprehensive bibliometric analysis of the 100 most-cited MPNST articles by utilizing Elsevier's Scopus to identify all relevant published and indexed articles referring to MPNST, thereby aiming to elucidate the pertinent research findings regarding the disease's pathophysiology and therapeutic advancements. Articles were classified as basic science or clinical and analyzed for various bibliometric parameters. The majority of articles (75%) focused on clinical aspects, reflecting the extensive clinicopathological characterization of MPNSTs. Notable studies investigated prognostic factors, histological and immunohistochemical features, and diagnostic modalities. The identification of loss of function mutations in the polycomb repressive complex 2 emerged as a pivotal role, as it opened avenues for potential targets for novel therapeutic interventions. Newer articles (published in or after 2006) demonstrated higher citation rates, suggesting evolving impact and collaboration. This bibliometric analysis showed how developments in the understanding of MPNST pathophysiology and the creation of novel therapeutic strategies occurred throughout time. Changes that have been noticed recently could portend future innovative therapeutic approaches. [ABSTRACT FROM AUTHOR]

The Hannover classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. We have previously reported the reliability of the Koos system, but to date, no study has assessed the reliability of the similar Hannover classification. We present an assessment of the intrarater and interrater reliability of the Hannover classification system. After institutional review board approval was obtained, a cross-sectional group of the magnetic resonance imaging of 40 patients with vestibular schwannomas varying in size comprised the study sample. Four raters were selected to assign a Hannover grade to 50 total scans. Interrater and intrarater reliability was calculated and reported using Fleiss's kappa, Kendall's W, and intraclass correlation coefficient (ICC). Interrater observer reliability was found to be moderate when measured using Fleiss' kappa (0.49), extremely strong using Kendall's W (0.93), and excellent as calculated by ICC (0.88). The results were all statistically significant (P < 0.05). Intrarater reliability for Hannover grade ranged from 0.77 to 1.00 (substantial to perfect). By Kendall's W and ICC, all raters had near perfect or excellent agreement. The results were all statistically significant (P < 0.05). The Hannover classification is a reliable system for grading the size of vestibular schwannomas. This supports its continued use and previously published results of the literature in studies relying on this classification. Further studies are needed to evaluate its validity and determine its role in preoperative counseling and determining microsurgery and radiosurgery outcomes. [ABSTRACT FROM AUTHOR]

This study evaluated the characteristics of vestibular schwannomas (VS) in young patients, including clinical features, treatment, prognosis, and histopathologic characteristics. We retrospectively reviewed medical records and follow-up data for 36 pediatric patients <21 years of age who were surgically treated for VS in the Chinese PLA General Hospital between 2008 and 2019. Mean patient age was 17.4 years. Mean tumor size was 2.8 cm. Hearing loss (n = 32, 88.9%) and tinnitus (n = 20, 55.6%) were the most common symptoms. Ten patients (27.8%) had impaired facial nerve function after surgery. Gross total resection (GTR) was achieved in 26 cases (72.2%). The median tumor Ki-67 level was 5%. Tumor size was related to incomplete tumor resection (odds ratio, 0.2; 95% confidence interval, 0.1–0.9) and postoperative facial nerve dysfunction (odds ratio, 24.9; 95% confidence interval, 1.2–539.1). Tumor size was nonlinearly associated with prognosis and 2.2 cm corresponded to the inflection point at which the probability of tumor remnant and postoperative facial nerve dysfunction significantly increased. The GTR and low Ki-67 groups achieved better 3-year tumor control rate. Histopathologic findings confirmed the presence of cellular schwannoma subtype in young patients. Tumor size is an important factor affecting the prognosis of VS in young patients. For large VS, surgical treatment should be the first choice, rather than wait-and-scan. VS in young patients shows high tumor proliferation and a tendency to relapse. The cellular schwannoma subtype requires special attention; an accurate histopathologic diagnosis is necessary for young patients with VS, and a closer follow-up strategy should be adopted for cellular VS. [ABSTRACT FROM AUTHOR]

In patients with neurofibromatosis type 1 (NF1), it is important to accurately determine when plexiform neurofibroma (pNF) transforms to a malignant peripheral nerve sheath tumor (MPNST). The purpose of this study is to investigate the usefulness of diffusion-weighted imaging (DWI) in differentiating pNF and MPNST in NF1 patients. Among the NF1 patients who were referred to our hospital between 1985 and 2015, 10 cases of MPNST and 19 cases of pNF were included. We evaluated features of standard magnetic resonance imaging according to the differentiation criteria of malignancy from benignancy as previously reported, apparent diffusion coefficient (ADC) value based on the DWI and the correlation between ADC value and benignancy/malignancy. ROC analysis was performed to determine the appropriate cutoff value of ADC. There were significant differences between MPNST and pNF in the size of the tumor (P = 0.009), peripheral enhancement pattern (P = 0.002), perilesional edema-like zone (P = 0.0008), and intratumoral cystic change (P = 0.02). The mean and minimum values of ADC were significantly lower in MPNST than those in pNF (P = 0.03 and P = 0.003, respectively). When we set a cutoff value of mean ADC as 1.85 × 10–3 mm2/s, the sensitivity and specificity were 80% and 74%, respectively. The area under the curve value improved by adding the Wasa score to the mean ADC evaluation. ADC values determined by DWI are useful in differentiating MPNST from pNF and adding ADC evaluation to standard MRI evaluation improved the diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Although partial cystic degeneration is commonly observed in schwannoma, cases of totally cystic forms have also been reported. A literature review of cases describing totally cystic schwannoma was performed to assess their imaging characteristics. PubMed was queried with the phrases "totally cystic schwannoma," "purely cystic schwannoma," and "completely cystic schwannoma." A total of 19 papers encompassing 22 cases of reported totally cystic schwannoma were included. Patient characteristics, clinical presentation, and reported imaging characteristics were recorded. Computed tomography and magnetic resonance images from the papers were collected and reviewed by a senior musculoskeletal radiologist. The most frequent presenting location of these lesions was in spinal nerve roots. The interpretations of imaging reported in the papers described a homogeneous lesion that was isointense to slightly hyperintense to cerebrospinal fluid (CSF) on T1-weighted images. On contrast administration, the studies described a thin rim of "ring-like" enhancement around the lesion. Our reinterpretation of the imaging revealed heterogeneous lesions that were hyperintense to CSF on T1-weighted images. Post-contrast images typically demonstrated an irregularly thickened enhancing rim. Most images showed evidence of solid components in the lesion, with many containing enhancing soft tissue elements. The observed imaging features were not consistent with simple cystic lesions. Review of the imaging studies of the reported cases of completely cystic schwannoma did not produce any convincing examples of purely cystic lesions. The description of these lesions as "totally cystic" appears to be a misnomer and has diagnostic and therapeutic implications. [ABSTRACT FROM AUTHOR]

Vestibular schwannoma is the third most common benign intracranial tumor that can occur sporadically or be associated with neurofibromatosis type 2 (neurofibromatosis type 2 vestibular schwannoma [NF2-VS]). The aim of this study is to provide a comprehensive bioinformatic analysis of methylated-differentially expressed genes (MDEGs) in NF2-VS. Transcriptional sequencing datasets (GSE141801 and GSE108524) and gene methylation microarrays (GSE56598) from the Gene Expression Omnibus database were used to identify and analyze MDEGs in NF2-VS. A protein–protein interaction (PPI) network was built, and the hub genes and modules were identified. Finally, potential pharmacotherapy targeting MDEGs were extracted for NF2-VS. A total of 57 hypermethylation–low expression genes and 88 hypomethylation–high expression genes were identified. Pathways associated with aberrantly MDEGs included P13K-AKT, MAPK, and Ras, which were also involved in NF2-VS. Six hub genes (EGFR, CCND1 , CD53, CSF1R, PLAU , and FGFR1) were identified from the PPI network. Modification of the aforementioned genes altered cell-to-cell communication, response to stimulus, cellular regulation, and membrane and protein bindings. Thirty drugs targeting these pathways were selected based on the hub genes. Analysis of MDEGs may enrich the understanding of the molecular mechanisms of NF2-VS pathogenesis and lay the groundwork for potential biomarkers and therapeutic targets for NF2-VS. [ABSTRACT FROM AUTHOR]

Primary intracranial malignant peripheral nerve sheath tumors (MPNSTs) not associated with cranial nerves are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. In addition, we present our own experience managed with resection, radiotherapy, and first use of targeted therapy in a tumor of this type for a BRAF mutation identified during next-generation sequencing. Two databases, PubMed and Embase, and crossed references were queried for intracranial MPNSTs not associated with a cranial nerve. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analysis was performed to identify factors with survival benefit. A total of 56 patients (including the present case) were included from 743 literature results. There was a male/female ratio of 1.5:1 and mean diagnosis age of 29.7 ± 21.8 years. Seventy-one percent of cases were sporadic and 23% neurofibromatosis type 1 related. Median survival was 29 ± 22.1 months with 1-year survival of 60%. Factors associated on univariate analysis with reduced survival were subtotal resection (P = 0.05), older age (P = 0.023), triton histology (P < 0.001), and early recurrence (≤6 months) (P = 0.018). On multivariate analysis, gross total resection reduced mortality risk (P = 0.011), whereas triton histology (P = 0.017) and infratentorial tumor location (P = 0.037) increased mortality. We present a systematic review of intracranial MPNSTs not associated with a cranial nerve. These tumors have poor prognosis and benefit from aggressive resection, multimodal treatment, and close follow-up. Next-generation sequencing can show molecular alterations for potential targeted therapy. [ABSTRACT FROM AUTHOR]

Carefully preserving facial nerve function is crucial when using the translabyrinthine approach for vestibular schwannoma surgery. Nerve preservation can only be accomplished by employing rigorous surgical methods and having a thorough understanding of the relevant anatomy, including any variations. Anatomical variations in the path of the facial nerve are infrequent but are most commonly encountered in association with congenital abnormalities of the temporal bone or ossicles. We present a rare case of vestibular schwannoma with a bifurcated facial nerve having 2 origins at the brainstem. The patient underwent a right-sided microsurgical excision using the right translabyrinthine approach. Postoperative recovery went smoothly, resulting in a House-Brackmann scale of Grade I. This case emphasizes the importance of identifying and preserving the facial nerve during vestibular schwannoma resection. To avoid injury, intraoperative neurostimulation should be used to positively identify the facial nerve and its anatomical variations along its entire course. [ABSTRACT FROM AUTHOR]

Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) are rare tumors of mesenchymal origin. Here, the authors present a rare case of anaplastic HPC in the jugular foramen (JF). The authors also conduct a systematic review of the literature to examine the current fund of knowledge on JF HPC/SFTs. A systematic MEDLINE search was conducted using key words "hemangiopericytoma" OR "solitary fibrous tumor" AND "jugular foramen" OR "extracranial" OR "skull base." Clinicopathologic characteristics and outcomes of the present case were reviewed and compared with those in the literature. A 41-year-old male, who had undergone stereotactic radiation therapy 6 years ago for a presumed glomus jugulare tumor, presented to our institution with worsening dysphagia, hoarseness, persistent tongue weakness, and radiographic evidence of tumor progression. The patient underwent uncomplicated gross total resection with sacrifice of the infiltrated hypoglossal nerve. Histopathologic evaluation revealed anaplastic HPC/SFT (World Health Organization grade III). Review of the literature yielded 9 additional cases of JF HPC/SFT in 5 males (56%) and 4 females (44%), with a mean age of 49.6 years old. Patients commonly presented with pain (37.5%) and lower cranial nerve deficits (100%). Preoperative diagnoses included glomus jugulare (n = 2) or JF schwannomas (n = 3). All patients underwent microsurgical resection of the lesion, except for 1 who refused all treatment after diagnostic biopsy. The authors present the only reported case of anaplastic HPC of the JF. The illustrative case and those found on systematic review of the literature highlight the importance of tissue diagnosis and appropriate management. [ABSTRACT FROM AUTHOR]

Surgical strategy in vestibular schwannomas may require subtotal resection to preserve neurologic function. Residual tumor growth pattern and contrast enhancement in the immediate postresection period remain uncertain. We sought to evaluate changes in the enhancement pattern and volume of vestibular schwannomas after subtotal resection in the immediate postoperative period. Volumetric analysis of tumor size and enhancement patterns of vestibular schwannomas were measured on magnetic resonance imaging (MRI) scans obtained within 3 days of surgery, 3 months after surgery, and 1 year after surgery. Nineteen patients were eligible for inclusion in the study (9 male and 10 female) with an average age of 47 years. Contrast enhancement was absent in 6 of 19 (32%) of cases on the immediate postresection MRI with return of expected enhancement on subsequent studies. Volumetric analysis identified that tumors decreased in size by an average of 35% in the first 3 months (P = 0.025) after resection and 46% in the first year after resection (P < 0.01). Vestibular schwannomas that undergo subtotal resection tend to decrease in size over the first 3 months after resection. Residual tumor volume may fail to enhance on the immediate postresection MRI. Both of these findings could lead surgeons to misinterpret degree of resection after surgery and have implications for clinical decision making and research reporting in the scientific literature for vestibular schwannomas after subtotal resection. [ABSTRACT FROM AUTHOR]

Most surgeons face litigation related to the care of their patients, with specialties including neurosurgery facing a particularly high risk. Diagnosis and management of vestibular schwannomas can be challenging, potentially giving rise to medicolegal proceedings. Accordingly, a full appreciation of the medicolegal implications of treating these challenging tumors is warranted. A systematic search of the Westlaw Edge legal database was conducted to identify all cases of medicolegal proceedings related to the management of vestibular schwannomas. All cases identified by the search were screened in full, and relevant cases included for analysis. Variables pertaining to the nature of the case and legal outcomes were extracted. A total of 38 cases were included in this analysis from 11 U.S. states. Failure to diagnose and negligent surgery were the most common allegations. Neurosurgeons were the most frequently implicated specialists followed by otolaryngologists and radiologists. A verdict was reached in 30 cases, with the jury finding in favor of the defendant(s) in most cases (n = 26, 87.0%), a proportion that increased across each decade of the study period. Damages were paid out in 11 cases, with a mean value of $1,534,446. Mean value of damages paid in verdicts in favor of the plaintiff were larger than those in settlements ($2,116,543 and $1,385,457, respectively). The data presented provide a comprehensive overview of medicolegal proceedings related to the management of vestibular schwannomas. This study provides clinicians with a greater appreciation of the medicolegal implications of treating vestibular schwannomas. [ABSTRACT FROM AUTHOR]

We describe our single-institutional experience with magnetic resonance−guided stereotactic laser ablation (SLA) for the treatment of newly diagnosed and recurrent pediatric brain tumors. Eighteen consecutive ablation procedures were performed in 17 patients from March 2016−April 2020. Patient demographics, indications, procedures, neuroimaging features, and outcomes were reviewed retrospectively. Seventeen patients (mean age of 11.4 years, 11 boys, 6 girls) underwent SLA with a mean follow-up of 24 months (range: 3–45 months). Tumor histologies included pilocytic astrocytoma (n = 5), ganglioglioma (n = 3), low-grade glioma not otherwise specified (n = 4), glioblastoma (n = 2), meningioma (n = 1), medulloblastoma (n = 1), and metastatic malignant peripheral nerve sheath tumor (n = 1). SLA was first-line therapy in 10 patients. Mean procedure duration including anesthesia time was 328 minutes (range: 244–529 minutes), and mean postoperative length of stay was 1.5 days (range 1–5 days). The complication rate was 29%, which included 3 patients who experienced postoperative motor changes, which resolved within several weeks of surgery, 1 patient with self-limited intraoperative bradycardia and hypotension, and 1 patient who died postoperatively due to intracranial hemorrhage from a distant lesion. Twelve of 17 patients had a neuroimaging response after SLA (4 complete responses, 8 partial responses, 1 stable disease). Percentage of tumor shrinkage from baseline ranged from 33%−100% (mean 75%). Patients with low-grade glioma exhibited the best responses to SLA (range 3%−100% decrease; mean 90%; 36% complete response rate). SLA is a minimally invasive modality for the treatment of newly diagnosed and recurrent low-grade pediatric brain tumors. Low-grade glioma exhibited the best responses. Identification of ideal candidates for SLA, mitigation of perioperative complications, and demonstration of long-term outcomes need to be better defined in a clinical trial setting. [ABSTRACT FROM AUTHOR]

Malignant perineurioma is a rare subset of malignant peripheral nerve sheath tumors (MPNSTs) with ultrastructural and immunohistochemical features of perineurial differentiation, distinguishing it from other MPNSTs, which typically demonstrate Schwannian features. The clinical course and prognosis of this rare tumor is not well defined. The electronic medical records were searched for patients with a diagnosis of MPNST. Patients with a pathologic diagnosis of malignant perineurioma or MPNST with perineurial features were identified and further evaluated. Five patients with malignant perineurioma, or MPNST with perineurial features, were identified. Four patients (2 male and 2 female) were included with tumors associated with a common digital nerve, small muscular branch to the deltoid, sciatic nerve, and accessory nerve. One patient with the pathology diagnosis meeting inclusion criteria was excluded, as no clinical information was available for this patient. Patients in our series presented at varied stages of disease. Clinical courses after diagnosis of malignant perineurioma, where follow-up was available, were largely uncomplicated with regard to recurrence and metastatic disease. Careful follow-up is indicated, and further work is needed to characterize the clinical course of these rare tumors. [ABSTRACT FROM AUTHOR]

Surveillance imaging is a valid management option for selected vestibular schwannomas (VS). An ideal protocol for radiologic monitoring would highlight growth-related risk factors and tailor management accordingly. This study aims to identify variables associated with the growth of sporadic VS to enhance surveillance imaging, enable early intervention, and optimize outcomes. The review was conducted according to the PRISMA guidelines. A systematic review of 5 databases (PubMed, Ovid, Cochrane Library, Web of Science, and Google Scholar) was performed to identify negative and positive growth predictors of sporadic vestibular schwannomas. The search was limited to studies reported between January 2015 and January 2020. We conducted an individual patient data meta-analysis using a 1-stage multivariate mixed-effect logistic regression model. A total of 437 studies were identified, of which 25 met our criteria for full-text analysis. Articles that measured VS with comparable methods were determined eligible for meta-analysis inclusion. The selected articles were highly heterogeneous in their use of grading scales and assessment of tumor size. Our review showed that size at diagnosis (odds ratio, 1.15; 95% confidence interval, 1.11–1.18; P < 0.0001) and intracanalicular localization (odds ratio, 0.49; 95% confidence interval, 0.26–0.90; P = 0.023) were associated with VS growth. The factors most frequently reported as being associated with growth within the literature were size of VS at diagnosis and localization of an intracanalicular component. Greater attention should be placed on these criteria within the surveillance imaging algorithm for VS. [ABSTRACT FROM AUTHOR]