Cerebellopontine Angle Meningioma Research Articles

Characterizing Hearing Outcomes Following Treatment of Cerebellopontine Angle Meningiomas

Abstract Objectives To characterize treatment and hearing outcomes for cerebellopontine angle (CPA) meningiomas with inherent risks of hearing loss and identify predictors of hearing loss for surgically treated lesions. Design Retrospective chart review. Setting Tertiary care medical center. Participants Adult patients with CPA meningiomas impinging upon cranial nerve VIII and/or pretreatment hearing loss managed with microsurgery or stereotactic radiosurgery (SRS) with Gamma Knife at our center between 2012 and 2023. Main Outcome Measures Hearing preservation rate was determined from analysis of patients with pretreatment serviceable hearing for whom hearing-preserving treatment was attempted. Surgical patients were further analyzed using multivariable Cox proportional hazards regression models to identify factors predictive of postoperative hearing loss. Results We identified 80 patients with CPA meningiomas meeting inclusion criteria who were managed with either microsurgery (43, 54%) or radiosurgery (37, 46%). Following SRS, hearing was preserved in 88% of cases. Following microsurgery, hearing was preserved in 71% of patients—all patients who lost hearing had tumors involving the internal auditory canal (IAC). Among surgical patients only, multivariable analysis accounting for preoperative hearing, recurrence status, lesion size, and patient age, the preoperative imaging finding that the CPA meningioma surrounded the vestibulocochlear nerve was significantly associated with hearing loss (hazard ratio: 10.3, 95% confidence interval: 1.3–81.4, p = 0.02). Conclusion Most patients with meningiomas of the CPA can experience preservation of hearing, even when there is risk of hearing loss based on pretreatment evaluation. IAC invasion and surrounding of eighth nerve by tumor may portend poorer hearing outcomes in surgically managed patients.

Cerebellopontine angle metastasis from pancreatic cancer: a case report

Introduction: Pancreatic cancer metastasis to the cerebellopontine angle (CPA) is extremely rare and often misdiagnosed preoperatively. The clinical characteristics and prognosis of this uncommon condition remain largely unknown. Case presentation: We report the case of a 68-year-old male who presented with recurrent headaches, dizziness, and gait disturbances. The patient had undergone pancreaticoduodenectomy for pancreatic head adenocarcinoma two years prior. Preoperative imaging suggested a right CPA meningioma. The patient underwent resection of the CPA tumor under general anesthesia. Postoperative pathology revealed a metastatic pancreatic adenocarcinoma. Despite treatment with adjuvant chemotherapy, the patient developed widespread metastatic disease and succumbed 2 months after the CPA tumor resection. Discussion: The rarity of pancreatic cancer metastasizing to the CPA presents diagnostic challenges, as evidenced by the initial misdiagnosis of meningioma in this case. The clinical presentation can mimic benign conditions, leading to delays in appropriate management. This case underscores the importance of considering metastatic disease in patients with a history of cancer, even when presenting with symptoms typical of more common CPA lesions. Conclusion: Vigilant monitoring is crucial in pancreatic cancer patients, as neurological symptoms may herald metastatic spread to uncommon sites like the CPA. Despite surgical intervention, widespread metastasis can lead to poor outcomes. Early diagnosis and a high index of suspicion are essential for optimal management of these rare cases.

Application of 5T glutamate chemical exchange saturation transfer imaging in brain tumors: preliminary results.

Glutamate chemical exchange saturation transfer (GluCEST) is a non-invasive CEST imaging technique for detecting glutamate levels in tissues. We aimed to investigate the reproducibility of the 5T GluCEST technique in healthy volunteers and preliminarily explore its potential clinical application in patients with brain tumors. Ten volunteers (4 males, mean age 29years) underwent three 5T GluCEST imaging scans. The reproducibility of the three imaging GluCEST measurements was assessed using one-way repeated measures analysis of variance (ANOVA), generalized estimating equations, and linear mixed models. Twenty-eight patients with brain tumors (10 males, mean age 54years) underwent a single GluCEST scan preoperatively, and t-tests were used to compare the differences in GluCEST values between different brain tumors. In addition, the diagnostic accuracy of GluCEST values in differentiating brain tumors was assessed using the receiver work characteristics (ROC) curve. The coefficients of variation of GluCEST values in healthy volunteers were less than 5% for intra-day, inter-day, and within-subjects and less than 10% for between-subjects. High-grade gliomas (HGG) had higher GluCEST values compared to low-grade gliomas (LGG) (P < 0.001). In addition, cerebellopontine angle (CPA) meningiomas had higher GluCEST values than acoustic neuromas (P < 0.001). The area under the curve (AUC) of the GluCEST value for differentiating CPA meningioma from acoustic neuroma was 0.93. 5T GluCEST images are highly reproducible in healthy brains. In addition, the 5T GluCEST technique has potential clinical applications in differentiating LGG from HGG and CPA meningiomas from acoustic neuromas.

Surgical Approaches for Cerebellopontine Angle/Petroclival Meningiomas

Considering that most meningiomas are pathologically benign, tumors located in the cerebellopontine angle and petroclival area should be reduced as much as possible, and radiation therapy should be administered if necessary. Consequently, relatively good preservation of cranial nerve function and local lesion control can be expected. However, because the lesions are generally located deep, and are surrounded by various important structures, performing surgical procedures is difficult, and careful management of the surgical strategy is important to avoid complications. Surgical outcomes have dramatically improved with the development of skull base and microsurgical techniques. The main surgical approaches for cerebellopontine angle meningiomas and petroclival meningiomas currently include the anterior and posterior combined transpetrosal, anterior transpetrosal, and lateral suboccipital approaches. Furthermore, with the recent developments in endoscopic surgery, minimally invasive surgery for skull base meningiomas has gradually been introduced. In this article, we explain the preoperative checkpoints, selection of the surgical approach, and surgical techniques for the resection of cerebellopontine angle meningiomas and petroclival meningiomas.

Case Report: Marfan’s Syndrome with Neurofibromatosis Type-2

Background Marfan’s syndrome (MFS) and neurofibromatosis type-2 (NF-2) are rare autosomal dominant diseases caused due to mutations in chromosome number 15 and 22, respectively. The chance of both the diseases occurring in the same patient is extremely rare. Case presentation In this report a rare case of a 16-year-old boy having a coexistence of both MFS and NF-2 is reported. The clinical findings consisted of musculoskeletal abnormalities consisting of laxity of joints, positive Steinberg thumb sign test, positive Walker-Murdoch wrist test, dolichostenomelia, and arachnodactyly. Anthropometric abnormalities reported an increase in lower segment height than the upper segment. Diagnostic assessment revealed pectus carinatum, multiple meningioma, and heterogeneous lesions in bilateral cerebellopontine angle that were ruled out as bilateral schwannoma confirming the diagnosis of MFS and NF-2. However, both must be regarded as novel mutations, and as the position of the two genes is unrelated, it is most probable that two different mutations have occurred. β-blocker was recommended as a prophylactic measure to minimize aortic root stiffness and control aortic root dilatation. Furthermore, surgery and radiation therapy were planned for the management of NF-2; however, the patient expressed skepticism regarding the course of treatment and follow-ups; as a result, this data was reported at the time of discharge with non-specified duration of follow-ups. Conclusions This case report demonstrates a rare case of MFS which is caused due to mutation in chromosome number 15 along with NF-2 which is caused due to mutation in chromosome number 22. Since the positions of the two genes are unrelated, it is concluded that two distinct mutations have occurred. As a result, this report highlights a rare coexistence of both mutations, which will benefit the medical profession in enhancing future studies.

A case of cerebellopontine angle meningioma presenting as neurovascular compression syndrome of the 8th cranial nerve

A 54-year-old female patient presented with paroxysmal tinnitus and vertigo for 2 years, which have repeatedly occurred while rotating her neck, and lasted about 10 seconds. An anticonvulsant medication was prescribed with a diagnosis of microvascular compression syndrome on the 8th cranial nerve and audiovestibular evaluation and magnetic resonance imaging (MRI) scan were appointed a week later. In her next visit, she reported the disappearance of paroxysmal audiovestibular symptoms after medication. In the left ear, canal paresis and abnormal auditory brainstem response were observed. In MRI, a large meningioma in the cerebellopontine angle in the vicinity of the internal auditory canal orifice was detected, that was surgically resected by a neurosurgeon. After surgical removal of the tumor, she reported continuous dizziness due to vestibular nerve injury, but the paroxysmal attack of tinnitus and vertigo disappeared without anticonvulsant medication. This case suggests that an imaging study is mandatory when diagnosing microvascular compression syndrome on the 8th cranial nerve.

POLR2A Mutation is a Poor Prognostic Marker of Cerebellopontine Angle Meningioma.

Recent molecular analyses have shown that the driver genetic mutations of meningiomas were associated with the anatomic location. Among these, POLR2A mutation is common among lesions in the skull base, mainly in the cerebellopontine angle (CPA). The objective of this study was to investigate the efficacy of POLR2A mutation as a prognostic marker for CPA meningiomas. We retrospectively analyzed the clinical data of 70 patients who had World Health Organization grade I CPA meningiomas. Somatic DNA was analyzed by Sanger sequencing and microsatellite array to examine for NF2 , AKT1 , KLF4 , SMO , and POLR2A mutations and 22q loss. Genetic and clinical parameters were analyzed to identify the factors related with tumor recurrence. We detected clearly the clinical features of the CPA cases with POLR2A mutation. Compared with cases without POLR2A mutation, cases with POLR2A mutation had more meningothelial type ( P = 6.9 × 10 -4 ), and higher rate of recurrence ( P = .04). We found that the poor prognostic factors associated with the recurrence of CPA meningiomas were POLR2A mutation ( P = .03, hazard ratio [HR] 9.38, 95% CI 1.26-70.0) and subtotal resection (STR) ( P = 5.1 × 10 -4 , HR 63.1, 95% CI 6.09-655.0). In addition, in the group that underwent STR, POLR2A mutation was a poor prognostic factor associated with tumor recurrence ( P = .03, HR 11.1, 95% CI 1.19-103.7). POLR2A mutation and STR were the poor prognostic markers associated with the recurrence of CPA meningioma. For CPA meningioma cases that underwent STR, only POLR2A mutation was a poor prognostic factor. Detecting POLR2A mutation may be a cost-effective, easy, and useful marker for prognostication.

Comparative assessment of methods of the operative treatment of facial nerve damage caused during cerebellopontine angle neurinoma and meningioma removals

The aim of this research paper is to point out the preconditions for facial nerve damage during CPA tumour removals and, in such cases, the appropriate choice of reconstructive surgery. Materials and methods. In Uzhhorod National University, during the period of 2008 to 2019, surgical treatment of 212 patients with neurinomas and meningiomas of the CPA has been carried out. We have analyzed the cases of 35 (16.5%) patients with intraoperative damage of the facial nerve. The mentioned 35 patients underwent appropriate clinical examinations during the post-operative period, which confirmed the facial nerve damage to one degree or another according to the House-Brackmann scale. The clinical signs manifested as full eyelid contact with slight effort and slight facial asymmetry during maximal effortful laughter. Slight synkinesias were noticeable, and there were no contractures until the expression of clinical signs corresponding to grade 6 - total nerve paralysis in 5 patients. Results. The research demonstrated that patients with neurinomas larger than 3 cm in size are 5 times more likely to undergo intraoperative damage to the facial nerve than patients with the same tumour but 3 cm or less in size and 5 times more likely than patients with meningiomas as a whole. In the group of patients aged 20-40, there were twice as many men; in the group aged 40-50, women predominated; among patients older than 50, there were equal numbers of men and women. Remote catamnesis was traced in 19 patients, and contact with the rest of the patients was lost due to the war. Among the interviewed patients, 58% of the anastomosis was performed in the first 3 months after the initial surgery, 21% - in 4-6 months, and 21% - in more than 12 months. The optimal timing of reinnervation after the initial surgery is the first 6 months after tumour removal. Сonclusions. Nerve damage is more common during the removal of neurinomas 4cm or bigger in size. Reinnervation is accomplished by anastomosing the central end of the hypoglossal or accessory nerves to the peripheral end of the facial nerve, and both procedures are equally effective. Reinnervation should be performed 2 to 3 months after confirming nerve injury, but no later than 6 months.

A SURPRISE DIAGNOSIS FROM A UNILATERAL HEARING LOSS AND VERTIGO CASE FROM CEREBELLOPONTINE ANGLE TUMOR

Meningiomas are generally benign intracranial tumors that arise from the dural coverings of the brain. They represent approximately one-third of all primary intracranial tumors and about 10-15% of cerebellopontine angle (CPA) tumors. Meningiomas develop from arachnoid cells and have been previously observed to be slow-growing. Despite their benign classification, these tumors can impact cranial nerves leading to a myriad of symptoms including hearing loss, imbalance or vertigo, tinnitus, and diminished facial sensation. Technology such as computerized tomography (CT) and magnetic resonance imaging (MRI) are vital tools in the definitive diagnosis of CPA meningiomas.

Neurological outcomes after gamma knife radiosurgery for symptomatic skull base meningiomas based on their locations: Single institution experience

Background and objectiveGross total resection of skull base meningioma is so challenging due to its relevant high morbidity. Gamma knife radiosurgery is concerned by providing a favorable therapeutic option in the management of SBM. This study aims to evaluate the neurological outcome after GKRS as an adjuvant or primary treatment for SBM according to their locations. MethodsThis retrospective cross-sectional study consisted of 108 patients with SBM who underwent GKRS as an adjuvant or primary treatment. We found 40 patients with cavernous sinus meningioma (CSM), 36 patients with petroclival meningioma (PCM), and 22 patients with cerebellopontine angle meningioma (CPM). 81.1% of whom were female (n = 90) with a median age of 52.68 years. The mean tumor volume was 4.5 cm3 and the mean marginal dose was 13 Gy. ResultsTumor control was achieved in 96.4 % of patients at a median follow-up of 38.4 months. Over all 17 of 108 patients (15.6%) report improvement in their neurological symptoms. Patients with CPM demonstrated lower rates of neurological symptoms improvement compared to patients with PCM and CSM. Deterioration of neurological symptoms after GKRS developed in 11 patients (10.1%) which was more reported by patients with CSM than the others. The most improvement in cranial nerve deficit was in CN Ⅵ, Ⅴ, VIII among patients with CSM, PCM, and CPM respectively. ConclusionGKRS is acceptable as a primary or adjuvant treatment for SBM by providing an appreciable rate of improvement in neurological symptoms.

Cerebellopontine angle meningioma in a patient presented as acute cerebrovascular accident.

Here, the authors present a 66-year-old male patient with diabetes, hypertension, and hyperlipidemia who presented to the emergency department of our hospital with sudden onset walking difficulty (ataxia). On examination, the patient was fully conscious. There was no associated cranial nerve deficit, hearing loss, or focal/lateralizing weakness. All sensory modalities were intact. However, the patient had a gait impairment. Romberg and tandem gait tests were positive with the tendency to sway to the left. The patient was admitted with suspicion of acute cerebrovascular disease. The initial noncontrast brain computed tomography and subsequent diffusion MRI were inconclusive. A later brain MRI with contrast revealed a homogeneously contrast enhancing meningioma in the left CPA. The differential diagnosis of sudden onset ataxia is broad and should include the assessment of a possible CPA lesion. Sudden onset ataxia by a CPA meningioma is very rare as meningiomas grow very slowly. A brain MRI with contrast is essential for its diagnosis. Although stroke is the main cause of sudden onset ataxia in a patient with cerebrovascular risk factors, yet other less common causes may be found as in this case of CPA meningioma.

Surgical outcomes of premeatal and retromeatal cerebellopontine angle meningioma in Vietnam: a single-center prospective cross-sectional study.

A prospective study on 33 patients treated with microsurgery from August 2020 to May 2022 at the Neurosurgery Center, Viet Duc University Hospital. The mean age of 27 females (85%) and 6 (15%) males was 54±12 years. Based on their location to the IAC, there were 16 premeatal cases (49%) (anterior to the IAC) and 17 retromeatal cases (15%) (posterior to the IAC). The time of diagnosis of the retromeatal group was later (16.5 vs. 9.7 months), the average tumor size of the 2 groups was not different, but when there was brainstem compression, the average tumor size of retromeatal group was larger (49 vs. 44mm). The clinical presentations of the retromeatal group were related to the cerebellar symptoms, while trigeminal neuropathy symptoms all came from the premeatal group. Gross total resection of the premeatal group was 31% and of the retrometal group was 71%. The results of preserving the facial nerve function of the premeatal group were lower (44 vs. 82%). Postoperative Karnofsky score of the retromeatal group improved, while the premeatal group did not change. Classification of CPA meningiomas according to their location to the IAC plays an important role in diagnosis and treatment, affecting clinical symptoms, surgical strategy as well as surgical outcomes.

Differences in Hearing, Balance, and Quality-of-Life Outcomes in Petroclival Versus Nonpetroclival Posterior Fossa Meningiomas.

To compare hearing, tinnitus, balance, and quality-of-life treatment outcomes of petroclival meningioma and nonpetroclival cerebellopontine angle meningioma cohorts. A retrospective cohort study of 60 patients with posterior fossa meningiomas, 25 petroclival and 35 nonpetroclival, who were treated at a single tertiary care center between 2000 and 2020. A survey battery that included the Hearing Effort of the Tumor Ear, Speech and Spatial Qualities of Hearing, Tinnitus Functional Index, Dizziness Handicap Inventory (DHI), and Short Form Health Survey. Petroclival and nonpetroclival cohorts were matched for tumor size and demographic features. Differences between groups in hearing, balance outcomes, and quality of life and patient factors that influence posttreatment quality of life. Petroclival meningioma patients reported poorer audiovestibular outcomes with a higher rate of deafness in the tumor ear (36.0% versus 8.6%, p = 0.032) and lower functional hearing by the Hearing Effort of the Tumor Ear, Speech and Spatial Qualities of Hearing (76.6 [6.1] versus 82.0 [4.4], p < 0.001). Current dizziness rate was higher (48.0% versus 23.5%, p = 0.05), with more severe dizziness by DHI (18.4 [4.8] versus 5.7 [2.2], p < 0.001). Both cohorts had similar high quality of life and low tinnitus severity indices. Quality-of-life Short Form Health Survey predictors were tumor size (p = 0.012) and DHI (p = 0.005) in multivariable analysis. Hearing and dizziness treatment outcomes of petroclival meningioma are poorer relative to other posterior fossa meningiomas. Despite audiovestibular outcome distinctions, the overall posttreatment quality of life was high for both petroclival and nonpetroclival meningioma.

Cerebellopontine angle meningiomas: LINAC stereotactic radiosurgery treatment

ObjectivesTo evaluate the efficacy of treatment with linear accelerator-based stereotactic radiosurgery (LINAC) in cerebellopontine angle meningiomas. MethodsWe analyzed 80 patients diagnosed with cerebellopontine angle meningiomas between 2001 and 2014, treated with stereotactic radiosurgery (SRS), of whom 81.9% (n=68) were women, with an average age of 59.1 years (32–79). SRS was applied as primary treatment in 83.7% (n=67) and in 16.3% (n=13) as an adjuvant treatment to surgery. SRS treatment was provided using LINAC (Varian 600, 6MeV) with M3 micromultilamines (brainLab) and stereotactic frame. The average tumor volume was 3.12cm3 (0.34–10.36cm3) and the coverage dose was 14Gy (12–16Gy). We performed a retrospective descriptive analysis and survival analysis was performed with the Kaplan–Meier method and multivariate analysis to determine those factors predictive of tumor progression or clinical improvement. ResultsAfter an average follow-up period of 86.9 months (12–184), the tumor control rate was 92.8% (n=77). At the end of the study, there was an overall reduction in tumor volume of 32.8%, with an average final volume of 2.11cm3 (0–10.35cm3). The progression-free survival rate at 5, 10 and 12 years was 98%, 95% and 83.3% respectively. The higher tumor volume (p=0.047) was associated with progression. There was clinical improvement in 26.5% (n=21) of cases and clinical worsening in 16.2% (n=13). Worsening is related to the radiation dose received by the brainstem (p=0.02). Complications were 8.7% (7 cases) of hearing loss, 5% (4 cases) of brain radionecrosis, and 3.7% (3 cases) of cranial nerve V neuropathy. Hearing loss was related to initial tumor size (p=0.033) and maximum dose (p=0.037). The occurrence of radionecrosis with the maximum dose (p=0.037). ConclusionsTreatment of cerebellopontine angle meningiomas with single-dose SRS using LINAC is effective in the long term. Better tumor control rates were obtained in patients with small lesions.

Meningiomas de ángulo pontocerebeloso: tratamiento con radiocirugía mediante LINAC

ObjectivesTo evaluate the efficacy of treatment with linear accelerator-based stereotactic radiosurgery (LINAC) in cerebellopontine angle meningiomas. MethodsWe analyzed 80 patients diagnosed with cerebellopontine angle meningiomas between 2001 and 2014, treated with stereotactic radiosurgery (SRS), of whom 81.9% (n=68) were women, with an average age of 59.1years (32-79). SRS was applied as primary treatment in 83.7% (n=67) and in 16.3% (n=13) as an adjuvant treatment to surgery. SRS treatment was provided using LINAC (Varian600, 6MeV) with M3 micromultilamines (brainLab) and stereotactic frame. The average tumor volume was 3.12cm3 (0.34-10.36cm3) and the coverage dose was 14Gy (12-16Gy). We performed a retrospective descriptive analysis and survival analysis was performed with the Kaplan-Meier method and multivariate analysis to determine those factors predictive of tumor progression or clinical improvement. ResultsAfter an average follow-up period of 86.9months (12-184), the tumor control rate was 92.8% (n=77). At the end of the study, there was an overall reduction in tumor volume of 32.8%, with an average final volume of 2.11cm3 (0-10.35cm3). The progression-free survival rate at 5, 10 and 12years was 98%, 95% and 83.3% respectively. The higher tumor volume (P=.047) was associated with progression. There was clinical improvement in 26.5% (n=21) of cases and clinical worsening in 16.2% (n=13). Worsening is related to the radiation dose received by the brainstem (P=.02). Complications were 8.7% (7 cases) of hearing loss, 5% (4 cases) of brain radionecrosis, and 3.7% (3 cases) of cranial nerveV neuropathy. Hearing loss was related to initial tumor size (P=.033) and maximum dose (P=.037). The occurrence of radionecrosis with the maximum dose (P=.037). ConclusionsTreatment of cerebellopontine angle meningiomas with single-dose SRS using LINAC is effective in the long term. Better tumor control rates were obtained in patients with small lesions.

Features of postoperative hearing function changes in patients with cerebellopontine angle and intratemporal tumors other than vestibular schwannomas.

Tumors around the cerebellopontine angle (CPA) and temporal bone can potentially affect hearing function. In patients with such tumors other than vestibular schwannomas (VSs), auditory tests were investigated before and after surgery to characterize the auditory effect of each tumor and to determine prognostic factors. A total of 378 patients were retrospectively evaluated for hearing functions before and after surgery. These 378 patients included 168 with CPA meningioma, 40 with trigeminal schwannoma (TS), 55 with facial nerve schwannoma (FNS), 64 with jugular foramen schwannoma (JFS), and 51 with CPA epidermoid cyst (EPD). Preoperative hearing loss was observed in 124 (33%) of the 378 patients. Of these 124 patients, 38 (31%) experienced postoperative hearing improvement. Postoperative hearing deterioration occurred in 67 (18%) of the 378 patients. The prognostic factors for postoperative hearing improvement were younger age and the retrocochlear type of preoperative hearing disturbance. Tumor extension into the internal auditory canal was correlated with preoperative hearing loss and postoperative hearing deterioration. Preoperative hearing loss was observed in patients with FNS (51%), JFS (42%), and MGM (37%), and postoperative hearing improvement was observed in patients with JFS (41%), MGM (31%), and FNS (21%). Postoperative hearing deterioration was observed in patients with FNS (27%), MGM (23%), and EPD (16%). According to the results of this study in patients with CPA and intratemporal tumors other than VS, preoperative retrocochlear hearing disturbance was found to be a prognostic factor for hearing improvement after surgery. Among the tumor types, JFS and MGM had a particularly favorable hearing prognosis. The translabyrinthine approach and cochlear nerve section should be avoided for these tumors, regardless of the patient's preoperative hearing level.

Aumento da frequência de pneumonia em cães com meningioma em rombencéfalo ventral

ABSTRACT: Intracranial tumors occurring in specific brain regions, such as the cerebellopontine angle, may be associated with cranial nerve dysfunction and dysphagia in humans and animals. Although dysphagia is a known risk factor for pneumonia, only postoperative pneumonia has been investigated in veterinary medicine. This study aimed to describe the clinical and pathological features of dogs with untreated intracranial meningiomas and concomitant pneumonia. Data from post-mortem examination registries from 2011 to 2021 were used (n=23). The frequency of pneumonia and other characteristics were compared between dogs with meningiomas in the ventral rhombencephalon region (VR group; n=13) and those with meningiomas in other intracranial sites (OIS group; n=10). The frequency of pneumonia was higher in the VR group than in the OIS group (n=5 vs. n=0; P=0.039). Plaque-like lesions were also more common in the VR group than in the OIS group (P=0.012). Dogs with concomitant pneumonia had cerebellopontine angle (n=3) and basilar meningiomas (n=2), mainly plaque-like lesions extending to or from other brain areas. In dogs with concomitant pneumonia, meningiomas had invasive (n=5) and compressive (n=3) growth behaviors and nerve roots involved in the swallowing process were frequently affected. Microscopically, these meningiomas were classified as atypical (n=4) and meningiomas (n=1). The reported clinical signs included anorexia (n=3), adipsia (n=1), and dysphagia (n=1). Our findings suggest untreated dogs with ventral rhombencephalon meningiomas may develop cranial nerve damage and aspiration pneumonia.

RADT-27. FRACTIONATED RADIOTHERAPY AS FIRST-LINE TREATMENT FOR INTRACRANIAL MENINGIOMAS

Abstract BACKGROUND Meningiomas are the most common primary brain tumour, and patients requiring intervention typically undergo surgical resection as first-line therapy. However, fractionated radiotherapy (fRT) as primary treatment remains an option for patients with larger tumours and surgical contraindications, although outcome prediction in this group remains uncertain. We aimed to assess the clinical factors that contribute to treatment failure in a cohort of meningiomas treated with fRT as first-line therapy. METHODS Patients treated with primary fRT for intracranial meningiomas at our institution from November 1, 1998 to December 30, 2017 were reviewed. Those who received upfront surgical resection, radiosurgery, or had less than 6 months of clinical follow up were excluded. We applied logistic regression and Cox regression analysis to ascertain key predictors of treatment failure, progression-free survival (PFS), and adverse events following radiotherapy. RESULTS Our cohort included 147 tumours, of which 25 progressed after fRT (median PFS of 3.45 years). Tumours that progressed following RT had a larger median gross tumour volume (GTV) than those that did not (32.3cm3 vs 20.2cm3,p = 0.03768). Pre-RT GTV greater than 11.27cm3 was independently predictive of treatment failure. Larger pre-RT GTV was also associated with significant (grade 3/4) adverse events following fRT. Finally, cerebellopontine angle meningiomas were more prevalent in the group that progressed (20% vs 3.3%, p = 0.0046), whereas cavernous sinus and optic nerve sheath meningiomas had longer PFS (p = 0.0067). CONCLUSION We present the largest known cohort of meningiomas treated with fRT as first line therapy and find pre-RT tumour GTV and location to be the critical predictors of outcome, adding to the discussion of treatment considerations in this heterogeneous disease.

Total Resection of Cerebellopontine Angle Meningioma via Presigmoid Transmastoid Approach: An Otologist's Perspective.

Cerebellopontine angle meningiomas (CPAMs) are benign tumors that arise from the dura mater of the petrosal surface of the temporal bone, lateral to the trigeminal nerve. This study aimed to describe 1 case of CPAMs violating the mastoid and highlight the unique superiority of the presigmoid transmastoid approach for this type of CPAMs from an otologist's perspective. One case of specific CPAMs treated by total resection via presigmoid transmastoid approach in otomicrosurgery was described. A patient was referred for the left intracranial space-occupying lesion found in physical examination. Surgical resection via presigmoid transmastoid approach was performed and there was no sign of recurrence of tumor 2 years after the operation. Presigmoid transmastoid approach in otomicrosurgery is suitable for CPAMs invading the mastoid. It is suggested that neurosurgeons and ear surgeons should comprehensively analyze the type and extent of the tumor and flexibly adopt surgical methods to ensure it is the best for patients.

Surgical management of large cerebellopontine angle meningiomas: long-term results of a less aggressive resection strategy.

Cerebellopontine angle (CPA) meningiomas present many surgical challenges depending on their volume, site of dural attachment, and connection to surrounding neurovascular structures. Assuming that systematic radical resection of large CPA meningiomas carries a high risk of permanent morbidity, the authors adopted an alternative strategy of optimal resection followed by radiosurgery or careful observation of the residual tumor and assessed the efficiency and safety of this approach to meningioma treatment management. This single-center retrospective cohort study included 50 consecutive patients who underwent surgery for meningioma between January 2003 and February 2020. The most common main dural attachments of the meningiomas were posterior (42%) and superior (26%) to the internal auditory meatus. The suboccipital retrosigmoid route was the most routinely used (92%). At the last follow-up examination, 93% of the patients with normal preoperative facial nerve (FN) function retained good House-Brackmann (HB) grades of I and II, whereas 3 patients (7%) displayed intermediate HB grade III FN function. Hearing preservation was achieved in 86% of the patients who presented with preoperative serviceable hearing, and recovery after surgery was achieved in 19% of the patients experiencing preoperative hearing loss. In order to preserve all cranial nerve function, gross-total resection was obtained in 26% of patients. Of the 35 patients who had undergone subtotal resection, 20 (57%) had been allocated into a wait-and-rescan treatment approach and 15 (43%) underwent upfront Gamma Knife surgery (GKS). The mean postoperative tumor volume was 1.20 cm3 in the upfront GKS group and 0.73 cm3 in the wait-and-rescan group (p = 0.08). Tumor control was achieved in 87% and 55% of cases (p < 0.001), with a mean follow-up of 85 and 69 months in the GKS and wait-and-rescan groups, respectively. The 1-, 5-, and 7-year tumor progression-free survival rates were 100%, 100%, and 89% in the GKS group and 95%, 59%, and 47% in the wait-and-rescan group, respectively (p < 0.001). Optimal nonradical resection of large CPA meningiomas provides favorable long-term tumor control and functional preservation. Adjuvant GKS does not carry additional morbidity and appears to be an efficient adjuvant treatment.