Induced phase separation of mutant NF2 imprisons the cGAS-STING machinery to abrogate antitumor immunity.

Missense mutations of the tumor suppressor Neurofibromin 2 (NF2/Merlin/schwannomin) result in sporadic to frequent occurrences of tumorigenesis in multiple organs. However, the underlying pathogenicity of NF2-related tumorigenesis remains mostly unknown. Here we found that NF2 facilitated innate immunity by regulating YAP/TAZ-mediated TBK1 inhibition. Unexpectedly, patient-derived individual mutations in the FERM domain of NF2 (NF2m) converted NF2 into a potent suppressor of cGAS-STING signaling. Mechanistically, NF2m gained extreme associations with IRF3 and TBK1 and, upon innate nucleic acid sensing, was directly induced by the activated IRF3 to form cellular condensates, which contained the PP2A complex, to eliminate TBK1 activation. Accordingly, NF2m robustly suppressed STING-initiated antitumor immunity in cancer cell-autonomous and -nonautonomous murine models, and NF2m-IRF3 condensates were evident in human vestibular schwannomas. Our study reports phase separation-mediated quiescence of cGAS-STING signaling by a mutant tumor suppressor and reveals gain-of-function pathogenesis for NF2-related tumors by regulating antitumor immunity.

Comparative analysis of upfront stereotactic radiosurgery and watchful waiting in the management of newly diagnosed vestibular schwannomas: a systematic review and meta-analysis.

Vestibular schwannomas (VS) are benign intracranial tumors posing significant management challenges. This study aims to compare the outcomes of stereotactic radiosurgery (SRS) and watchful waiting (WW) in the management of newly diagnosed VS, integrating findings from both retrospective and the pioneering V-REX prospective trial. Adhering to PRISMA guidelines, a systematic review was conducted using MEDLINE, Embase, and Cochrane databases. Studies directly comparing SRS with WW for newly diagnosed VS were included. Primary outcomes focused on hearing preservation assessed through the AAO-HNS or Gardner-Robertson hearing classification scales and tumor progression, with secondary outcomes focusing on neurological symptoms, and the need for further treatment. Thirteen studies encompassing 1,635 patients (WW: 891; SRS: 744) were included.While no significant difference was found in serviceable hearing loss at last follow-up (RR = 1.51, [95%CI: 0.98, 2.32], p = 0.06), significant differences favoring WW were observed in pure tone audiometry (PTA) (MD = -13.51 [95%CI: -22.66, -4.37], p = 0.004) and word recognition score (WRS) (MD = 20.48 [95%CI: 9.72, 31.25], p = 0.0002). Analysis of tumor progression indicated no overall significant difference in risk between SRS and WW (RR = 0.40, [95%CI 0.07, 2.40], p = 0.32), but subgroup analysis suggested a lower risk with SRS in certain contexts. The need for further treatments favored SRS (RR = 0.24, [95%CI: 0.07, 0.74], p = 0.007). No significant differences were found in tinnitus and imbalance between the two groups. This comprehensive analysis suggests no marked difference in functional hearing preservation between SRS and WW in managing VS. However, untreated tumors commonly necessitate additional interventions. These findings highlight the need for individualized treatment decisions and underscore the importance of continued monitoring. The study advocates for further prospective trials to refine management strategies for VS.

Conservative or surgical management of orbital schwannomas: a population-based case series.

INTRODUCTION: Orbital schwannomas (OS) are rare occurrences with no more than 500 cases reported in the literature. The tumor's potential to compromise the delicate neuro-ophthalmic structures within the orbit prompts surgical removal. Tumor removal is performed by ophthalmologists, often requiring a multidisciplinary surgical approach. The literature contains a very limited number of cases managed non-surgically. However, the inherent risks of orbital surgery warrant a comparison of the outcomes of conservative and surgical management strategies. AIMS: To review the national Swedish experience with the management of orbital schwannomas. METHODS: The study center is the primary Swedish referral center for the multidisciplinary management of orbital tumors, including schwannomas. During the period of 2005 to 2021, 16 patients with an OS diagnosis were managed at the center. RESULTS: Four patients initially underwent surgery where gross total resection (GTR) was achieved in three (75%) and subtotal resection (STR) in one (25%) case. The remaining 12 patients, who had a low risk of neuro-ophthalmic impairment, were managed conservatively with radiological and clinical examinations at regular intervals. After an average follow-up of 17 months, surgery was performed in three of these cases (25%). No recurrences or tumor growths were detected on radiological follow-ups (mean 50 months), and all patients experienced postoperative improvement at clinical follow-up (mean 65 months). The remainder of the conservatively treated patients (n=9) experienced no clinical progression (mean 30 months). A slight radiological tumor progression was detected in one patient after 17 months. CONCLUSION: There were no differences in long-term outcome between patients who had been managed with early surgery and those operated later after an initially conservative management. Conservatively treated patients had minimal to no symptoms and remained clinically stable throughout the follow-up period. Based on these findings, conservative management may successfully be adopted in cases with mild symptoms, no signs of compressive optic neuropathy and low risk of neuro-ophthalmic impairment. Conversion to surgical management is indicated upon clinical deterioration or tumor growth. Based on the findings of this study a decision tree for the management of orbital schwannomas is suggested.

Risk factors of postoperative trigeminal neuropathy in surgical treatment of trigeminal schwannomas.

OBJECTIVE: Trigeminal schwannomas are rare benign tumors originating from the Schwann cells of the trigeminal nerve. Despite the common occurrence of trigeminal neuropathy in trigeminal schwannomas, a detailed analysis has not yet been performed because of the rarity of this disease. This study aimed to analyze trigeminal neuropathy in trigeminal schwannoma resection and identify the risk factors for postoperative worsening of trigeminal neuropathy. METHODS: A retrospective analysis of 86 surgical cases was performed at our institution between 1975 and 2018. Obtained parameters included age, sex, diagnosis, reoperation, tumor size, tumor location, presence or absence of cysts, surgical approach, degree of tumor removal, and pre/postoperative trigeminal neuropathy. Uni- and multivariate analyses were performed to identify the risk factors for worsening postoperative sensory disturbances. RESULTS: Of 83 patients, 58.1% had preoperative trigeminal neuropathy. Postoperative sensory disturbance occurred in 27.9%, with worsening in two cases and de novo symptoms in 22 cases. Regarding risk factors for worsening postoperative sensory disturbances, older age, smaller tumor size, middle and posterior (MP) type, gross total removal (GTR), and anterior transpetrosal approach were identified in the univariate analysis, while MP type and GTR were identified in the multivariate analysis. CONCLUSIONS: This study analyzed trigeminal neuropathy in trigeminal schwannomas in detail and identified tumor location and removal rate as risk factors for worsening postoperative sensory disturbances. Treatment strategies to reduce the risk of trigeminal neuropathy should be considered.

Comprehensive analysis of radiological and surgical predictors in cervical sympathetic schwannomas: a novel staging approach and its implications.

BACKGROUND: Vagal schwannomas are well-documented, but cervical sympathetic chain schwannomas (CSCS) are rare, with most knowledge from case reports. This study aims to identify radiological predictors of misdiagnosis and factors guiding surgical approaches based on tumor size and extent. METHODS: An ambispective analysis was conducted on 21 cases of CSCS, examining preoperative data, intraoperative findings and the questionnaire to identify the potential predictors. Tumors were classified into three types based on their relationship with the carotid sheath, and this classification was correlated with vessel ligation and postoperative neural outcomes. RESULTS: An excellent agreement was found between radiologist on new classification system(Kappa:0.89). Tumor classification revealed a diverse distribution, with 6 cases identified as Type 1, 6 as Type 2, 5 as Type 3, and 4 as Type 3S. The necessity of external carotid artery (ECA) ligation correlated with the tumor type. Type 3 tumors required ECA ligation in 50% of cases, while Type 1 and Type 2 tumors predominantly involved vascular preservation. Postoperative complications included vagal palsy in 28.5% of cases and first bite syndrome in 71.4%. CONCLUSION: Accurate preoperative planning and a novel staging system can enhance surgical outcomes and reduce postoperative complications as validated by our study.

[Our approach to the treatment of vestibular schwannomas with arachnoid dissection of the facial nerve]. / Nash podkhod k lecheniyu vestibulyarnykh shvannom s primeneniem metodiki arakhnoidal'noi dissektsii litsevogo nerva.

Preserving the function of the facial nerve is extremely important in surgery for vestibular schwannomas. Two methods of arachnoid dissection are described for resection of vestibular schwannoma via retrosigmoid approach (from the brain stem and internal auditory canal). OBJECTIVE: To evaluate the results of arachnoid dissection of the facial nerve from internal auditory canal when resecting the vestibular schwannoma. MATERIAL AND METHODS: We analyzed 61 patients with vestibular schwannomas. Patients were divided into 2 groups depending on surgical technique. We estimated facial nerve function before and after surgery, preoperative dimension of vestibular schwannoma and extent of resection. The influence of various factors on extent of resection and postoperative facial nerve function was studied. RESULTS: Vestibular schwannoma resection from the brain stem was performed in 30 patients, arachnoid dissection - in 31 patients. There was no significant between-group difference. Gross total resection was performed in 78.7% of cases. Both techniques demonstrated similar results regarding extent of resection. Arachnoid dissection showed the advantage regarding facial nerve function immediately after surgery (p=0.012) and 6 months later (p<0.001). Normal facial nerve function in 6 months after arachnoid dissection was observed in 80.7% of patients. Preoperative dimension of tumor influenced facial nerve function in addition to technique of resection (p=0.001). CONCLUSION: We identified the factors influencing facial nerve function after resection of vestibular schwannoma. Surgical technique was the most significant factor. These data expand and popularize arachnoid dissection in surgery of vestibular schwannomas.

[Minimally invasive removal of dumbbell shaped schwannomas with transforaminal lumbar fusion: a retrospective study with a minimum 3-year follow-up]. / Minimal'no invazivnoe udalenie ganteleobraznykh shvannom s transforaminal'nym poyasnichnym spondilodezom: retrospektivnoe issledovanie s minimal'nym 3-letnim katamnezom.

Currently, there are no standards in surgical treatment of dumbbell-shaped tumors of lumbo-foraminal region. OBJECTIVE: To evaluate the effectiveness and long-term results of minimally invasive resection of dumbbell-shaped lumbar schwannomas Eden type 2 and 3 combined with transforaminal lumbar interbody fusion and transpedicular stabilization. MATERIAL AND METHODS: A retrospective study included 13 patients (8 men and 5 women) with lumbar dumbbell tumors Eden type 2 and 3 who underwent minimally invasive facetectomy through posterolateral anatomical corridor, microsurgical tumor resection and MI TLIF. We analyzed intraoperative parameters, neurological functions (ASIA scale), clinical characteristics (ODI, SF-36), and complications. Resection quality and area of the multifidus muscle were assessed according to MRI data. All patients were followed-up throughout at least 3-year. RESULTS: Surgery time was 147 min, blood loss - 118 ml, hospital-stay - 7 days. Clinical parameters significantly improved in the follow-up period: ODI score decreased from 72 to 12 (p=0.004), SF-36 PCS increased from 26.24 to 48.51 (p=0.006) and MCS score increased from 29.13 to 53.68 (p=0.002). According to MRI data, no tumor recurrences and severe muscle atrophy (>30%) were observed after 3 years in all cases. Superficial wound infection occurred in 1 (7.7%) case. There were normal neurological functions (ASIA type E) in all patients. CONCLUSION: Minimally invasive facetectomy through posterolateral approach with MI TLIF technology can be used for safe and effective resection of dumbbell-shaped schwannomas Eden type 2 and 3.

[Neurofibromatosis type 2 in the otorhinolaryngological practice]. / Neirofibromatoz 2-go tipa v praktike vracha-otorinolaringologa.

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disease (frequency 1 in 25-90 000) characterized by the formation of tumors of the central nervous system due to a mutation in the NF2 gene on chromosome 22q12. Bilateral vestibular schwannomas are recognized as absolute diagnostic criteria of NF2 and occur in 95% of patients, are accompanied by hearing impairment, manifest at the age of 18-24 years. Skin manifestations can precede vestibular schwannomas for several years and predict the course of the disease: neurofibromas, cafe-au-lait macules, hypopigmented spots, recently described mesh capillary malformations. Despite the benign nature of schwannomas, they can lead to hearing loss, vestibular dysfunction, facial nerve paralysis, gait disorders, pain and convulsions, there is a risk of early death from compression of the brain stem. The probability of progressive hearing loss is partly determined by the type of mutation. We described a clinical case of NF2 in a 21-year-old patient with bilateral vestibular schwannomas without hearing loss, whose skin examination by ENT specialist revealed this disease. The importance of the presented observation is that the doctor should assume neurofibromatosis type 2 in a young patient with bilateral vestibular schwannomas. It is necessary to undertake a further examination of this patient, including: skin examination for the identification of characteristic neurofibromas and cafe-au-lait macules, consultation with an ophthalmologist, neurologist, MRI of the brain and spinal cord with contrast, genetic analysis - for timely initiation of therapy that prevents hearing loss and vestibular disorders.

Characterization of vestibular schwannoma tissues using liquid chromatography-tandem mass spectrometry analysis of specific peptide fragments separated by in-sample tryptic protein digestion followed by mathematical analysis.

Vestibular schwannoma is the most common benign neoplasm of the cerebellopontine angle. Its first symptoms include hearing loss, tinnitus, and vestibular symptoms, followed by cerebellar and brainstem symptoms, along with palsy of the adjacent cranial nerves. However, the clinical picture has unpredictable dynamics and currently, there are no reliable predictors of tumor behavior. Hence, it is desirable to have a fast routine method for analysis of vestibular schwannoma tissues at the molecular level. The major objective of this study was to verify whether a technique using in-sample specific protein digestion with trypsin would have the potential to provide a proteomic characterization of these pathological tissues. The achieved results showed that the use of this approach with subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of released peptides allowed a fast identification of a considerable number of proteins in two differential parts of vestibular schwannoma tissue as well as in tissues of control healthy samples. Furthermore, mathematical analysis of MS data was able to discriminate between pathological vestibular schwannoma tissues and healthy tissues. Thus, in-sample protein digestion combined with LC-MS/MS separation and identification of released specific peptides followed by mathematical analysis appears to have the potential for routine characterization of vestibular schwannomas at the molecular level. Data are available via ProteomeXchange with identifier PXD045261.

Fully neuroendoscopic resection of cerebellopontine angle tumors through a retrosigmoid approach: a retrospective single-center study.

The objective of this study is to preliminarily investigate the surgical safety, efficacy, techniques, and clinical value of fully neuroendoscopic surgery for the resection of cerebellopontine angle (CPA) tumors via a retrosigmoid approach. The clinical data of 47 cerebellopontine angle area (CPA) tumors that were treated by full neuroendoscopic surgery from June 2014 to June 2023 were retrospectively analyzed. The efficacy and advantages of the surgical techniques were evaluated based on indicators such as duration of the surgery, neuroendoscopic techniques, intraoperative integrity of nerves and blood vessels, extent of tumor resection, outcomes or postoperative symptoms, and incidence of complications. The 47 cases of cerebellopontine angle tumors include 34 cases of epidermoid cysts, 7 cases of vestibular schwannomas, and 6 cases of meningiomas. All patients underwent fully neuroendoscopic surgery. Twenty tumors were removed using the one-surgeon two-hands technique, and 27 tumors were removed using the two-surgeons four-hands technique. The anatomical integrity of the affected cranial nerves was preserved in all 47 cases. None of the patients suffered a postoperative hemorrhage, cerebrospinal fluid leak, and aseptic or septic meningitis, or died. The rate of total tumor resection was 72.3% (34/47), and the symptom improvement rate was 89.4% (42/47). All patients were followed up for 2 to 12 months, and none died nor showed any signs of tumor recurrence. By analyzing 47 fully neuroendoscopic resections of CPA tumors using the posterior sigmoid sinus approach in our center, we believe that such method allows complete, safe, and effective resection of CPA tumors and is thereby worthy of clinical promotion.

Schwannomas of Brain and Spinal Cord.

Schwannomas are benign tumors originating from the Schwann cells of cranial or spinal nerves. The most common cranial schwannomas originate from the eight cranial nervevestibular schwannomas (VS). VS account for 6-8% of all intracranial tumors, 25-33% of the tumors localized in the posterior cranial fossa, and 80-94% of the tumors in the cerebellopontine angle (CPA). Schwannomas of other cranial nerves/trigeminal, facial, and schwannomas of the lower cranial nerves/are much less frequent. According to the World Health Organization (WHO), intracranial and intraspinal schwannomas are classified as Grade I. Some VS are found incidentally, but most present with hearing loss (95%), tinnitus (63%), disequilibrium (61%), or headache (32%). The neurological symptoms of VSs are mainly due to compression on the surrounding structures, such as the cranial nerves and vessels, or the brainstem. The gold standard for the imaging diagnosis of VS is MRI scan. The optimal management of VSs remains controversial. There are three main management options-conservative treatment or "watch-and-wait" policy, surgical treatment, and radiotherapy in all its variations. Currently, surgery of VS is not merely a life-saving procedure. The functional outcome of surgery and the quality of life become issues of major importance. The most appropriate surgical approach for each patient should be considered according to some criteria including indications, risk-benefit ratio, and prognosis of each patient. The approaches to the CPA and VS removal are generally divided in posterior and lateral. The retrosigmoid suboccipital approach is a safe and simple approach, and it is favored for VS surgery in most neurosurgical centers. Radiosurgery is becoming more and more available nowadays and is established as one of the main treatment modalities in VS management. Radiosurgery (SRS) is performed with either Gamma knife, Cyber knife, or linear accelerator. Larger tumors are being increasingly frequently managed with combined surgery and radiosurgery. The main goal of VS management is preservation of neurological function - facial nerve function, hearing, etc. The reported recurrence rate after microsurgical tumor removal is 0.5-5%. Postoperative follow-up imaging is essential to diagnose any recurrence.

Operative management of trigeminal schwannomas: based on a modified classification in a study of 93 cases.

BACKGROUND: Advances in microscopic and endoscopic surgical techniques have outpaced traditional classification and transcranial surgical strategies, especially with reference to the treatment of trigeminal schwannomas (TSs). A modified TS classification is proposed and appropriate surgical strategies are discussed. METHODS: The cases of 93 patients who underwent surgical treatment in Beijing Tiantan Hospital in the previous 6 years were analyzed retrospectively, and a literature review was conducted. RESULTS: Classification is based on surgical direction. Tumors were classified as follows: type A, backward orientation, located in the orbit or orbit and middle cranial fossa (8 cases, 8.6%); type B, upward orientation, located in the pterygopalatine fossa, infratemporal fossa or pterygopalatine fossa, infratemporal fossa, and middle cranial fossa (23 cases, 24.7%); type C, forward and backward orientations, located in the middle cranial fossa, posterior cranial fossa or both (58 cases, 62.4%); and type D, located in multiple regions (4 cases, 4.3%). 91.40% of patients underwent gross total resection (GTR) with 29 cases receiving endoscopic resection of whom 93.10% (27/29) experienced GTR. CONCLUSION: The 93 cases were satisfactorily divided into four types, according to tumor location and surgical orientation, enabling safe and effective removal by appropriate surgery.

Partial excision of schwannomatosis with fascicular invasion occurring in the ulnar nerve above the elbow: A 1-year follow-up study.

Although not as common as solitary lesions, multiple schwannomas do occur, even in single nerve lesions. We report a rare case of a 47-year-old female patient who presented with multiple schwannomas with inter-fascicular invasion in the ulnar nerve above the cubital tunnel. Preoperative MRI revealed a 10-cm multilobulated tubular mass along the ulnar nerve above the elbow joint. During excision under 4.5° loupe magnification, we separated three ovoid yellow-colored neurogenic tumors of different sizes, but there were still remaining lesions as it was difficult to completely separate lesions from the ulnar nerve due to the risk of iatrogenic nerve ulnar nerve injury. The operative wound was closed. Postoperative biopsy confirmed the diagnosis of the three schwannomas. During the follow-up, the patient recovered without neurological symptom or limitations in range of motion, and there were no neurological abnormalities. At 1year after surgery, small lesions remained in the most proximal part. However, the patient had no clinical symptoms and was satisfied with the surgical results. Although a long-term follow-up is necessary for this patient, we were able to obtain good clinical and radiological results.

[New classification and approaches to the treatment of schwannomatosis]. / Novaya klassifikatsiya i podkhody k terapii shvannomatozov.

Schwannomatoses is a new classification unit for all the hereditary diseases caused by chromosome 22 damage followed by multiple benign neoplasms of the peripheral and central nervous system. Schwannomatosis occurs as a result of damage to different genes: NF2, SMARCB1, LZRT1, loss of heterozygosity of the long arm of chromosome 22. Nevertheless, clinical manifestations are similar. Molecular diagnostics not only confirms the diagnosis, but also predicts the course of disease. Thus, the most severe clinical manifestations are observed in patients with violation of semantic sequences and reading frame shift in exons 2-13 of the NF2 gene. A more favorable course with less number of tumors is observed in patients with somatic mosaicism. Stereotactic irradiation and surgery are the main treatment options for schwannomatosis. However, there is evidence of effective targeted therapy with bevacizumab (inhibitor of vascular endothelial growth factor). Bevacizumab is used in patients with bilateral vestibular schwannomas and high risk of hearing loss, as well as for intramedullary tumor growth control.

[Expression of estrogen and progesterone receptors in vestibular schwannomas]. / Analiz ekspressii retseptorov estrogena i progesterona v vestibulyarnykh shvannomakh.

INTRODUCTION: Stereotactic radiosurgery is one of the main treatments for vestibular schwannomas (VS). Their feature is frequent post-radiation pseudoprogression. This may be due to hormonal status of patients. OBJECTIVE: To analyze expression of progesterone and estrogen receptors in women and men with VS. MATERIAL AND METHODS: Immunohistochemical analysis of expression of progesterone (PR) and estrogen receptors (ER) after biopsy was performed in 240 patients with VS between 2018 and 2021. ER/PR expression was assessed in men (n=120) and women (n=120) in 3 age subgroups: young age (18-44 years), middle age (45-59 years) and old age (60-79 years). Each subgroup included 40 patients. Statistical analysis was performed using the Mann-Whitney test and MedCalc software. RESULTS: ER expression is not typical for VS (men - 1 (0.01%), women - 3 (2.5%)). At the same time, PR expression was found in 29 (24.2%) men and 21 (17.5%) women. We found no significant difference in expression of ER and PR between men and women. However, variability in PR expression was revealed, i.e. predominance of this indicator in young women (p=0.0463) and middle-aged men (p=0.0110). Expression of PR was similar in elderly patients (p=0.2382). CONCLUSION: The established incidence of PR expression may be one of the probable causes affecting development and duration of VS pseudoprogression after radiosurgery without clear relationship between sex and age. Further prospective research is needed to predict the risks of pseudoprogression.

Stereotactic radiosurgery ensures an effective and safe long-term control of Koos grade IV vestibular schwannomas: a single-center, retrospective, cohort study.

PURPOSE: Stereotactic radiosurgery (SRS) is a standard treatment modality for vestibular schwannomas (VSs). However, there is a paucity of data on tumor control and neurological preservation for larger VSs. We aimed to investigate the long-term effectiveness of SRS for Koos grade IV compared with I-III VSs. METHODS: We included 452 patients with VSs (50 Koos grade IV and 402 Koos grade I‒III) who were treated with SRS at our institution from 1990 to 2021. Tumor control and functional preservation were calculated using the Kaplan-Meier method and compared between groups with the log-rank test. RESULTS: The median post-SRS follow-up period was 68 months. Progression-free survival rates were 91% at 5 and 10 years for Koos grade IV VSs, and 95% and 92%, respectively, for Koos grade I‒III VSs (p = 0.278). In Koos grade IV VSs, functional preservation rates of the facial and trigeminal nerves were both 96% at 5 years (both 98% for Koos grade I‒III VSs; facial, p = 0.410; trigeminal, p = 0.107). Hearing preservation rates were 61% at 5 years for Koos grade IV VSs and 78% for Koos grade I-III VSs (p = 0.645). Symptomatic transient tumor expansion was more common with Koos grade IV VSs (8.0% vs. 2.5%, p = 0.034), although all related symptoms diminished in accordance with tumor shrinkage. CONCLUSION: SRS may contribute to long-term tumor control and adequate neurological preservation in the treatment of Koos grade IV VSs, comparable to those in the treatment of Koos grade I‒III VSs.

Quantitative Chemical Exchange Saturation Transfer Imaging of Amide Proton Transfer Differentiates between Cerebellopontine Angle Schwannoma and Meningioma: Preliminary Results.

Vestibular schwannomas are the most common tumor at the common cerebellopontine angle, followed by meningiomas. Differentiation of these tumors is critical because of the different surgical approaches required for treatment. Recent studies have demonstrated the utility of amide proton transfer (APT)-chemical exchange saturation transfer (CEST) imaging in evaluating malignant brain tumors. However, APT imaging has not been applied in benign tumors. Here, we explored the potential of APT in differentiating between schwannomas and meningiomas at the cerebellopontine angle. We retrospectively evaluated nine patients with schwannoma and nine patients with meningioma who underwent APT-CEST MRI from November 2020 to April 2022 pre-operation. All 18 tumors were histologically diagnosed. There was a significant difference in magnetization transfer ratio asymmetry (MTRasym) values (0.033 ± 0.012 vs. 0.021 ± 0.004; p = 0.007) between the schwannoma and meningioma groups. Receiver operative curve analysis showed that MTRasym values clearly differentiated between the schwannoma and meningioma groups. At an MTRasym value threshold of 0.024, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive values for MTRasym were 88.9%, 77.8%, 80.0%, and 87.5%, respectively. Our results demonstrated the ability of MTRasym values on APT-CEST imaging to discriminate patients with schwannomas from patients with meningiomas.

[Prospects of Drug Therapy of Vestibular Schwannoma].

Vestibular schwannoma (VS) is one of the most common types of benign tumors of the central nervous system. At present, the prevailing treatment methods of VS include surgery, stereotactic radiotherapy, and follow-up observation, etc. However, there is still no drug therapy available for treating VS. Although the surgical technique is relatively mature, the complications cannot be completely avoided. Furthermore, both the growth rate of different cases and patients' sensitivity to radiotherapy vary greatly. With the constant progress made in molecular biology research, most of the studies on the growth mechanism of VS focus on the upstream and downstream of neurofibromin 2 ( NF2) gene and merlin protein, and a number of corresponding targets, including receptor protein tyrosine kinase (RTK), vascular endothelial growth factor receptor (VEGFR), mammalian target of rapamycin complex 1 (mTORC1) and platelet derived growth factor receptor (PDGFR). It has been reported in some studies that quite a few drugs could inhibit the proliferation of VS cells. Most of the studies are still in the stage of in vitro cell experiment and/or animal experiment. A small number of studies have entered phase Ⅰ and phase Ⅱ clinical trials, but have not led to any clinical treatment yet. This paper provides a comprehensive understanding of the current status and the prospects of drug therapies of VS, which is conducive to the development of subsequent research.

Guidelines in the management of CNS tumors.

INTRODUCTION: Evidence-based, clinical practice guidelines in the management of central nervous system tumors (CNS) continue to be developed and updated through the work of the Joint Section on Tumors of the Congress of Neurological Surgeons (CNS) and the American Association of Neurological Surgeons (AANS). METHODS: The guidelines are created using the most current and clinically relevant evidence using systematic methodologies, which classify available data and provide recommendations for clinical practice. CONCLUSION: This update summarizes the Tumor Section Guidelines developed over the last five years for non-functioning pituitary adenomas, low grade gliomas, vestibular schwannomas, and metastatic brain tumors.

Interdisciplinary Approaches to Survivorship with a Focus on the Low-grade and Benign Brain Tumor Populations.

PURPOSE OF REVIEW: "Brain tumor is a bump in the road." Sheryl Crow a famous singer was quoted talking about her meningioma, a benign brain tumor that caused her to forget her lyrics. In this review, we focus on low-grade gliomas in adults and benign brain tumors, such as meningiomas, vestibular schwannomas, and pituitary tumors, since these individuals survive a long time and morbidity is a major issue. RECENT FINDINGS: As per the NCI dictionary definition, cancer survivorship focuses on the health and well-being of a person with cancer from the time of diagnosis until the end of life. This includes the physical, mental, emotional, social, and financial effects of cancer that begin at diagnosis and continue through treatment and beyond. The survivorship experience also includes issues related to follow-up care (including regular health and wellness checkups), late effects of treatment, cancer recurrence, second cancers, and quality of life. Family members, friends, and caregivers are also considered part of the survivorship experience (NCI Dictionary: https://www.cancer.gov/publications/dictionaries/cancer-terms ).