Angle Schwannoma Research Articles

Intracochlear signal in FIESTA-C and hearings of patients with cerebellopontine angle schwannoma

Background Hearing loss in patients with cerebellopontine angle (CPA) schwannoma, is thought to be caused by the damage to the cochlea and the cochlear nerve. Aim This study aimed to examine the relationships between the intracochlear signal in magnetic resonance imaging (MRI) and hearing in patients with CPA schwannoma. Material and method In 79 patients with CPA schwannoma, we retrospectively examined the signal in the cochlea on the affected side was compared with that on the unaffected side to determine signal degradation in fast imaging reagents steady-state acquisition with cycle phases (FIESTA-C) MRI. For hearing evaluation, pure tone audiometry (PTA), speech audiometry, distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR) were used. For each parameter, we examined the differences between the groups with and without signal degradation. Results In the hearing test results, the I-wave latency of ABR was significantly longer in the group with signal degradation in FIESTA-C (1.84 ± 0.35 msec vs. 2.04 ± 0.37 msec, p = 0.048). There was no statistically significant difference in other tests. Conclusion The MRI signal changes in the cochlear were related to the I-wave latency of ABR and reflected cochlear function. Significance We suggested the cochlear signal changes in CPA schwannoma patients related the hearing.

Partial hypoglossal-facial neurorrhaphy: a surgical technique.

This is a video demonstration of hemihypoglossal-facial neurorrhaphy. Any irreversible facial palsy more than House-Brackmann grade II is aesthetically problematic. Also, the functional and psychological impact associated with a higher grade of facial palsy is even worse. In this video, the procedure is demonstrated in a female patient with irreversible grade VI facial palsy and corneal opacity due to exposure keratitis 1 year following surgical excision of cerebellopontine angle (CPA) schwannoma. Postoperative outcomes are shown in another patient who underwent a similar procedure for establishing outcomes. The nasolabial fold and eye closure symmetry can be achieved with minimal or no hypoglossal morbidity. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID2290.

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.

Matched Cohort Analysis of the Effect of the Facial Recess Approach on Cerebrospinal Fluid Leak After Translabyrinthine Surgery for Schwannoma.

The facial recess approach during translabyrinthine surgery has been used to expose the eustachian tube (ET) for packing. We sought to determine the effect of this technique on the development of postoperative nasopharyngeal cerebrospinal fluid (CSF) leaks. Cohorts of patients with cerebellopontine angle schwannomas who underwent a facial recess approach or no facial recess approach were matched based on tumor size. Translabyrinthine surgery for tumor resection. Postoperative CSF leaks were recorded and nasopharyngeal CSF leaks were utilized as the primary outcome measure. Using an exact matching protocol based on tumor size, 102 patients were included in each group (204 total, 111 female, 93 male). Overall, 9 patients (4.4%) demonstrated a postoperative nasopharyngeal CSF leak. Postoperative CSF rhinorrhea was noted in 3.9% of the group who underwent a facial recess approach for packing of the ET and 4.9% of the group who did not undergo a facial recess approach. This rate was not significantly different between groups (p = 0.99, Odds ratio: 0.79, 95% CI: 0.15-3.8). Secondary variables including age, tumor size, a diagnosis of NF2, and the packing material used were not significant predictors of nasopharyngeal CSF leaks. CSF rhinorrhea is infrequent after translabyrinthine surgery. The incidence of this complication is not affected by whether or not a facial recess approach is performed during surgery to pack the ET. Based on these data, use of this technique should be based on surgeon comfort and preference.

Intratemporal facial nerve schwannomas: multicenter experience of 80 cases.

To provide more data on the clinical presentation and natural evolution of facial nerve schwannomas and to provide guidance for therapeutic decision making. A retrospective case review of eighty patients diagnosed with a facial nerve schwannoma between 1990 and 2018 in ten tertiary referral centers in Europe was performed. Patients' demographics, symptomatology, audiometry, anatomical site (segments involved), size and whenever possible volume measurement were registered. At presentation, transient or persistent facial palsy was the most common symptom, followed by hearing loss. The schwannoma involved more than one segment in the majority of the patients with the geniculate ganglion being most commonly involved. Initial treatment consisted of a wait and scan approach in 67.5%, surgery in 30% and radiation therapy in 2.5% of the patients. Tympanic segment schwannomas caused mainly conductive hearing loss and were more prone to develop facial palsy at follow-up. Internal auditory canal or cerebellopontine angle schwannomas presented with significantly more sensorineural hearing loss. Although modern imaging has improved diagnosis of this tumor, choosing the best treatment modality remains a real challenge. Based on the literature review and current findings, more insights into the clinical course and the management of facial nerve schwannomas are provided.

Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review.

Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.

Brain Stem and Audio-Vestibular Regulation.

The central pathologies present with perverted auditory perception and compromised postural control. Considering the existing controversy this study involves assessments of 100 cases of post fossa tumefactions in which a detailed clinical and neuro-otological (pure tone audiometry, electronystagmography, brainstem evoked response audiometry) profile is compared with their imaging patterns. The CP angle schwannomas (N = 26) presented with abnormal speech tests (N = 18), abnormal auditory adaptation (N = 7) and ABR with pathologically increased latency of wave V (N = 32), poor formation of wave I (N = 31) along with abnormal inter-wave interval (N = 32). In lesions (N = 32) compressing deeper nuclei, vermis and axial parts of brain stem, a gross truncal ataxia, incoordination, nystagmus, speech defects, subtotal deafness and bilateral ABR abnormalities were observed. The abnormal optomotor activities were seen as saccadic (N = 44) and deformed slow pursuit eye movements (N = 20). Inability to sustain holding function resulted in gaze nystagmus (N = 71), and poor timing manifested as fixation overshoots (N = 42). The midline cerebellar and upper brain stem lesions revealed bilateral OKN abnormalities whereas paramedian pathology showed only ipsilateral distortion. Caloric tests revealed culmination frequency as the most sensitive parameter for assessment of the hypo-reflexia in diffuse cerebellopathies while slow phase velocity in cases of posterior fossa lesion. The caloric hypo-activity appears to be of a better localizing value than the directional preponderance. The slow pursuit tracking revealed Type III curve perhaps due to defective regulation of slow movements in partially intact cerebellum (N = 15), while gross cerebellar dysfunctioning resulted into Type IV curve (N = 5).

An Unusual Variant of Cerebellopontine Angle Schwannoma in a Young Nepalese Girl

An unusual variant of cerebellopontine angle schwannomas is extremely rare. Histologically, the tumor has atypical changes misleading the diagnosis. We report 20-year-old Nepalese girl from far-eastern community presented with features of raised intracranial pressure and difficulty in walking. MR imaging revealed intensely contrast enhanced well defined huge solid tumor in right cerebellopontine angle region with foci of multiple cystic components. The tumor was displacing the brain stem structures with dilatation of lateral and third ventricles. The altered radiological finding made discrepancy diagnosis. Conventional angiography demonstrated major feeders from the auricular branch of the right external carotid artery. The tumor was embolized with polyvinyl alcohol particles followed by gross total lateral suboccipital excision. Histopathology unit detailed it as ancient schwannoma with pleomorphic changes.

Susceptibility weighted imaging - a problem-solving tool in differentiation of cerebellopontine angle schwannomas and meningiomas.

Background and purpose Vestibular schwannomas and meningiomas of the cerebellopontine angle can be differentiated by the presence of foci of blooming on susceptibility weighted imaging. Materials and methods In this retrospective study, magnetic resonance imaging with susceptibility weighted imaging sequence in addition to other routine sequences was done in 73 patients. All the cases were studied for the presence of foci of blooming within the tumor on susceptibility weighted imaging. Histopathological examination confirmed the diagnosis in all cases. Results There were 59 patients in the vestibular schwannoma group and 14 in the meningioma group. Susceptibility weighted imaging showed presence of blooming (due to microhemorrhages) in all the cases of cerebellopontine angle schwannomas. In the meningioma group, 13 cases showed no blooming within the lesion; one case showed blooming which was confirmed to be due to calcification on computed tomography study. For the detection of foci of blooming and predicting histopathologic diagnosis of schwannoma pre-operatively, susceptibility weighted imaging showed a sensitivity of 100%, specificity of 92%, positive predictive value of 98.3%, and negative predictive value of 100%. The Fisher exact test showed a statistically significant difference in the differentiation of vestibular schwannoma from meningioma on the basis of detection of blooming on susceptibility weighted imaging ( p < 0.0001). Conclusion Susceptibility weighted imaging is a problem-solving tool in making accurate pre-operative differentiation of vestibular schwannoma from meningioma.

Postoperative Complications and Readmission Rates Following Surgery for Cerebellopontine Angle Schwannomas.

To investigate the 30-day postoperative complication, readmission, and reoperation rates following surgery for cerebellopontine angle (CPA) schwannomas. Cross-sectional analysis. National surgical quality improvement program dataset (NSQIP) 2009 through 2013. All surgical cases with an International Classification of Diseases, 9th edition, Clinical Modification (ICD-9-CM) diagnosis code of 225.1, benign neoplasms of cranial nerves, and one of the following current procedural terminology (CPT) codes, were included: 61616, 61526, 61530, and 61520. Surgical resection as indicated by the CPT codes above. Demographics, comorbidities, 30-day postoperative complications, readmission rate, and reoperation rate. Overall, 404 cases were identified, of which 42.6% were men. The average age was 51 years. Comorbidities were present in 45.3%. NSQIP-tracked complications occurred in 9.7% of patients. Most common complications were wound infections including surgical-site infection and wound dehiscence (11 patients, 2.7%), sepsis (10 patients, 2.5%), blood loss (nine patients, 2.2%), and deep vein thrombosis (DVT; seven patients, 1.7%). Mortality occurred in four patients (1.0%). The complication rate was statistically higher in patients with comorbidities versus those without (10.2% versus 4.1%, p = 0.04). Patients with complications were more likely to undergo reoperation (2.5% with versus 4.1% without, p = 0.001). Unplanned readmissions occurred in 41 cases (10.1%) and reoperations occurred in 23 patients (5.7%). Most common NSQIP-tracked complications in excision of CPA neoplasms are infections, sepsis, blood loss, and deep vein thrombosis (DVT). Further, investigation of patients with unplanned readmission and reoperation are warranted. Neurotologists need to take an active role in the data to be gathered in the NSQIP database as it relates to vestibular schwannomas.

Morphometric analysis of posterior fossa in Indian CP angle acoustic schwannoma patients.

Aim:To study the morphometry of posterior fossa in Indian CP angle schwannoma patients in order to know its influence on the extent of excision of the CP angle acoustic schwannomas.Materials and Methods:One hundred cases of cerebellopontine angle schwannomas treated surgically by the senior author and 20 controls between January 2006 and June 2011 were consecutively investigated with computed tomography (CT) using the high-resolution CT bone windows before surgery. Evaluation of anatomic parameters of the petrous bone and posterior fossa cavity were done in all patients and controls. Data were entered in Excel software and were analyzed using NCSS software. All possible regression analysis was done to select the important variables to be included in the model to predict the excision of tumor with these variables. A prediction model was developed defining the binary outcome as total excision or subtotal excision as dependent variable and the morphometric data and grading of tumor as independent variables.Results:Interpetrous distance (IP) is the distance between the two petrous apices. Sigmoid distance (IS) distance is the distance between the two sigmoid points. Sigmoid point is the point at which the scalloped impression of the sigmoid sinus straightens to join the occipital bone posteriorly. SAG is the distance between the mid IP point and the mid-point on the inner wall of the occipital bone. The PM angle was 47.8±4.14 degrees (38-58), the PA angle was 42.68±4.47 degrees (34-53), the IP distance was 2.07±0.13 cm (1.5-2.8), the sagittal diameter of posterior fossa was 6.22±0.73 cm (5.1-9.8) and the intersigmoid distance was 9.45±0.73 cm (7.4-11). There was no significant gender difference in the posterior fossa morphometry between patients and controls. Inter-sigmoid distance and the petrous-apex angle were more in the Indians when compared to the European population mentioned in the Mathies and Samii study.Conclusions:The posterior fossa morphological parameters of the Indian and European population differ significantly. Inter-sigmoid distance and the petrous-apex angle were more in the Indians when compared to the Europeans. There is no significant gender difference in the morphometry of the Indians. There is no significant difference between the patients and the control groups. In our study the adhesions with surrounding structures along with the posterior fossa morphometry significantly affect the extent of excision.

Role of magnetic resonance imaging in evaluation of cerebellopontine angle schwannomas.

The aim of the present study was to evaluate the role of Magnetic Resonance Imaging (MRI) to localize and characterize the MR imaging features of cerebellopontine angle schwannomas and to compare with surgical/histopathological findings. It was a prospective study which included 19 patients, who presented with signs and symptoms s/o any lesion in the CP angle and were referred to the radiology department for MRI. All patients included in the study were subjected to detailed clinical history and physical examination following which MRI was carried out on Philips Gyroscan Achieva 1.5 Tesla unit and the standard protocol consisted of T1WI, T2WI, DWI and FLAIR images in axial, sagittal and coronal planes. Hearing abnormality was the most common presenting complaint in patients with CP angle schwannoma's followed by headache and tinnitus. Vestibulocochlear nerve was the most commonly involved nerve in patients with these lesions followed by involvement of trigeminal nerve. MRI was erroneous in giving provisional diagnosis of schwannoma in one case, which on subsequent surgery and histopathology was found to be a meningioma. The sensitivity of MRI for correctly diagnosing vestibular schwannoma was 100% and specificity was 92.86% with a positive predictive value of 94.12% and accuracy of 96.67%. MRI is considered as an excellent noninvasive investigation for CP angle schwannoma's. It can identify the site and extension of the lesions as well as the characteristic signal. Apart from diagnosing, MR imaging plays an important role in stratifying patients into appropriate treatment options.

Stitchless Fibrin Glue-Aided Facial Nerve Grafting after Cerebellopontine Angle Schwannoma Removal: Technique and Results in 15 Cases

Stitchless Fibrin Glue-Aided Facial Nerve Grafting after Cerebellopontine Angle Schwannoma Removal: Technique and Results in 15 Cases

Cerebellopontine angle schwannoma masquerading as malignant tumour in cytology fluid of cyst

CytopathologyVolume 26, Issue 1 p. 56-57 Correspondence Cerebellopontine angle schwannoma masquerading as malignant tumour in cytology fluid of cyst D. Gochhait, D. Gochhait Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorD. Chatterjee, D. Chatterjee Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorA. Bal, A. Bal Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorP. Dey, Corresponding Author P. Dey Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, India Correspondence: Dr P. Dey, Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India Tel.: +91-172-2755120; Fax: +91-172-2744401; E-mail: [email protected]Search for more papers by this author D. Gochhait, D. Gochhait Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorD. Chatterjee, D. Chatterjee Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorA. Bal, A. Bal Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, IndiaSearch for more papers by this authorP. Dey, Corresponding Author P. Dey Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh, India Correspondence: Dr P. Dey, Department of Cytology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India Tel.: +91-172-2755120; Fax: +91-172-2744401; E-mail: [email protected]Search for more papers by this author First published: 04 December 2013 https://doi.org/10.1111/cyt.12123Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume26, Issue1February 2015Pages 56-57 RelatedInformation

Usefulness of PRESTO Magnetic Resonance Imaging for the Differentiation of Schwannoma and Meningioma in the Cerebellopontine Angle

The principles of echo-shifting with a train of observations (PRESTO) magnetic resonance (MR) imaging technique employs an MR sequence that sensitively detects susceptibility changes in the brain. The effectiveness of PRESTO MR imaging was examined for distinguishing between cerebellopontine angle (CPA) schwannomas and meningiomas in 24 patients with CPA tumors, 12 with vestibular schwannomas, and 12 with meningiomas. Histopathological study of surgical specimens showed that 11 of the 12 schwannomas contained hemosiderin deposits and all had microhemorrhages. One meningioma contained hemosiderin deposits and two involved microhemorrhages. Abnormal vessel proliferation, and dilated and thrombosed vessels were observed in all schwannomas and in 4 meningiomas. In addition to MR imaging with all basic sequences, PRESTO MR imaging and computed tomography were performed. PRESTO imaging showed significantly more schwannomas (n = 12) than meningiomas (n = 2) exhibited intratumoral spotty signal voids which were isointense to air in the mastoid air cells (p < 0.001). These spotty signal voids were significantly associated with histopathologically demonstrated hemosiderin deposits (p < 0.001), microhemorrhages (p < 0.01), and abnormal vessels (p < 0.04). The visualization of spotty signal voids on PRESTO images is useful to distinguish schwannomas from meningiomas.

Magnetic Resonance Brain Imaging in Regularly Transfused Beta Thalassemia Major and Intermedia Subjects and Prevalence of Thrombophilia Mutations

Abstract 5175 Introduction/Background:Recent reports of magnetic resonance (MRI) brain imaging have emerged detecting covert cerebral infarcts in thalassemia subjects. The thalassemia phenotype, and splenectomy and hypercoagulation are suggested mechanisms. Methods:We conducted a retrospective review of all brain MRIs performed in thalassemia subjects at the Weill Cornell/New York Presbyterian Hospital Thalassemia Center over the past 15 years (yrs). Blood counts, platelet counts and ferritin levels at the time of MRI as well as genotype and phenotype diagnoses, splenectomy status and thrombophilia mutational analysis historically performed were reviewed. Results:16 thalassemia subjects: 7M:9F, mean age = 29. 9 yrs (range: 11 to 45 yrs) were identified who underwent brain MRI studies from 1998 to 2012. Brain MRIs were performed for evaluation of various symptoms including: headaches (6), dizziness (2), growth hormone efficiency (2), unilateral hearing loss (1), optic neuritis (1), cerebral hypoxia (1), acquired human immunodeficiency syndrome (1), s/p craniopharyngioma excision (1), and paresis (1).MRI findings included 3 chronic infarcts, 2 cerebral white matter disease images consistent with chronic ischemia, 1 acute infarct, 2 opacified maxillary sinuses, 1 sphenoid sinusitis, 1 acute hemorrhage, 1 recurrent hemorrhage, 1 cerebellopontine angle schwannoma and 4 unremarkable studies.Clinical diagnosis included: 12 Thalassemia Major (TM) subjects who were on regular red blood cell (RBC) hypertransfusion regimens since infancy to maintain pre-transfusion hemoglobin (Hgb) levels greater than 10 gm/dl and 4 Thalassemia Intermedia (TI) subjects (3M/1F) were periodically transfused until adolescence or early adulthood when they were placed on regular RBC hypertransfusion support owing to complications including extramedullary hematopoiesis causing spinal cord compression, progressive anemia with fatigue and thrombosis. All but 2 subjects were splenectomized; all but 6 subjects had platelet counts greater than 500 (mean platelet count = 567; range 175 to 1101). All were on iron chelation therapy including 2 Deferoxamine (DFO), 1 on DFO and Deferiprone (DFP) and 13 on Deferasirox (DFX). Prothrombotic genetic mutations were identified in 10 subjects including: (2) homozygous PAI-1, (5) heterozygous PAI-1, (2) homozygous MTHFR and (4) heterozygous for MTHFR; those 3 TM subjects with lacunar infarcts were heterozygous PAI-1 or negative for other thrombophilia mutations however 1 TM also had a patent foramen ovale. In addition, the 2 TI subjects with cerebral white matter disease had compound heterozygous MTHFR or PAI-1 in association with homozygous PAI-1 or homozygous MTHFR respectively. Conclusion:Chronic brain infarcts and cerebral white matter disease consistent with ischemia were detected on MRI in 5/16 adolescent and adult thalassemia subjects (31%): TM = 3/16 (19%) and TI = 2/16 (10%) thalassemia subjects. Headache, pain and dizziness were the predominant symptoms in those subjects with brain MRI findings of chronic infarcts and white matter disease. Thrombocytosis was common in all splenectomized subjects Homozygous and compound heterozygous co-inheritance of thrombophilia mutations PAI-1 and MTHFR were relatively more common in subjects with chronic infarcts and white matter disease. Further brain MRI studies need to be performed to address the prevalence, pathogenesis, risk factors, neurological and cognitive outcomes of brain infarcts in at risk adolescent and adult thalassemia subjects for the prevention and development of therapeutic strategies. Disclosures:No relevant conflicts of interest to declare.

Cerebellopontine Angle Schwannomas: Surgery, Hypofractionated Stereotactic Radiotherapy, Combined Therapy. Strategy for Harmless Therapy

Cerebellopontine Angle Schwannomas: Surgery, Hypofractionated Stereotactic Radiotherapy, Combined Therapy. Strategy for Harmless Therapy

High Resolution Three-dimensional T2*-weighted Imaging at 3T: Findings of Cerebellopontine Angle Schwannomas and Meningiomas

High Resolution Three-dimensional T2*-weighted Imaging at 3T: Findings of Cerebellopontine Angle Schwannomas and Meningiomas

Comparison of vestibular function between large cerebellopontine angle meningioma and schwannoma

Conclusion. Abnormal caloric and vestibular evoked myogenic potential (VEMP) responses are frequently encountered with a large cerebellopontine angle (CPA) schwannoma, while normal caloric responses and abnormal VEMPs are noted with a large CPA meningioma. This difference may possibly exist because schwannoma causes vestibular deficits via parenchymal involvement, while vestibular deficits in the meningioma are mostly due to compression neuropathy. Objectives. This study aimed to compare the tumor characteristics in relation to vestibular function, i.e. caloric and VEMP responses, between large-sized (>2.5 cm) meningioma and schwannoma in the CPA. Patients and methods. Five patients with large CPA meningioma and nine patients with large CPA schwannoma were enrolled in this study. Each patient underwent a battery of tests including audiometry, caloric test, VEMP test, and MRI study. Results. The meningioma group showed 20% caloric abnormality and 75% VEMP abnormality, while the schwannoma group revealed 100% caloric and 100% VEMP abnormalities. A significant difference existed in relation to caloric abnormality between the two groups, but not in relation to VEMP abnormality.

Schwannoma of the intermediate nerve

The intermediate nerve is seldom identified as the site of tumor origin in cerebellopontine angle schwannomas. A 29-year-old man presented with a 6-month history of slowly progressive hearing loss and dizziness; facial nerve weakness was not observed clinically. Magnetic resonance imaging revealed a tumor in the left cerebellopontine angle region extending up to the geniculate ganglion and along the course of the superficial petrosal nerve. A CT scan showed enlargement of the facial nerve canal. Microsurgery was performed via an extended retrosigmoid approach. Intraoperative and electrophysiological findings identified the intermediate nerve as the site of tumor origin.