Schwannoma Research Articles

Prominent auditory and balance disturbances in a patient with trigeminal nerve schwannoma

Trigeminal nerve schwannoma, a rare type of schwannoma, can be challenging to be diagnosed. Its initial clinical presentations may be subtle in nature but could deteriorate rapidly once the mass is large enough to compress the surrounding nerves. In this article, we report a case of a 55-year-old Malay female who complained of only numbness (without other symptoms) during her visit in the year 2014. As such, the otological findings were unremarkable. In the year 2017, her condition was worsening to the extent that she was not able to walk or stand independently and her hearing had dropped to a profound level in the right side. Low gain on the anterior and lateral right semicircular canals was found in video head impulse test, suggesting the hypofunction of the right semicircular system. The magnetic resonance imaging was carried out, and the presence of mass at the trigeminal nerve was confirmed. It is important to highlight that the auditory and balance can be prominently affected in trigeminal nerve schwannoma. Audiological and vestibular assessments are important to complement the diagnosis and prognosis of the patient.

Schwannoma with secondary erosion of mandible: A rare case

Schwannoma (also known as neurilemmoma, neurolemmoma, neurinoma, perineural fibroblastoma, peripheral glioma, and peripheral nerve sheath tumor) is a slow-growing, benign neoplasm derived from Schwann cells, which are sheath cells that cover myelinated nerve fibers The presented case was of schwannoma in a 20-year-old male patient, who presented with painless swelling at the left side angle of the mandible. Clinically, no symptoms other than facial deformity were noted. Panoramic radiograph showed radiolucency presenting as secondary erosion at left angle of mandible region. Fine needle aspiration cytology suggested cytomorphology of benign spindle cell lesion, which was then confirmed histologically as nerve sheath tumor. It was difficult to diagnose the condition clinically due to the rare clinical presentation of the peripheral nerve sheath tumor. The lesion was completely excised. Postoperative follow-up of one year was taken without any recurrence. We attempt to present the versatility of presentation of such tumor and its effect on adjacent bone. Also, we found out that fine needle aspiration cytology can play a significant role in diagnosing clinically perplexing presentations of rare tumors.

Diagnosis and management of intralabyrinthine schwannoma: case series and review of the literature.

Intralabyrinthine schwannoma (ILS) is a rare benign tumor affecting cochlear and vestibular nerves, whose symptoms are generally unspecific and frequently responsible for a late diagnosis. Radiological examinations, with particular reference to magnetic resonance imaging (MRI), represent the only diagnostic technique to identify ILS. On computed tomography ILS can only be indirectly suspected by the presence of surrounding bone remodeling, whereas MRI provides direct visualization of the neoplasm as a filling defect within the labyrinth with vivid contrast enhancement. At the same time, MRI is also helpful in defining ILS anatomical extension into adjacent structures and in planning therapeutic management. Here we report three representative cases of ILS with new pictorial imaging features to improve ILS early detection and optimize subsequent therapeutic management. (www.actabiomedica.it)

Revisiting the surgical corridors for cervical Type IIb-c dumbbell neurofibroma: A series of two unconventional approaches and review of literature.

Background:Cervical sub-axial dumbbell neurofibromas (NFs) account for nearly 20% of all NFs, with prognosis depending on the extent of excision. When majority of tumor is extra-foraminal (Tomaya's Type IIb and c), certain unconventional anterolateral or posterolateral neck approaches are used for maximum safe excision. In our article, we provide a brief review of the literature regarding various surgical approaches, emphasizing the utility of posterolateral or combined anterior and posterior neck approaches for such giant NF.Methods:We performed a retrospective analysis of prospectively maintained surgical databases, from our hospital discharge codes, for all cervical Type IIb-c dumbbell NF patients, who underwent surgery at our institution between 2015 and 2019. Clinical variables included age at admission, clinical presentation, and surgical difficulties, and the outcome was analyzed.Results:Four patients of age ranging from 22 to 45 years (M:F 3:1) were operated by posterolateral (n = 3) and combined anteroposterior (n = 1) approach. Three patients underwent near-total excision and one patient had total excision. One patient with tumor capsule attached to roots of upper brachial plexus had motor deficit, who was re-admitted for neurotization. There was no intraoperative complication.Conclusion:Posterolateral approach for cervical dumbbell giant NFs is safe, effective, and promises maximum safe excision. The major blood vessels including carotid artery or jugular veins in neck and vertebral artery at foraminal portion are directly under vision and control of surgeon. Despite near-total excision, wherein small part of adhered capsule is left, recurrence rate is low.

Schwannoma of the head-and-neck: Is it always about surgery?

Schwannoma of the head-and-neck: Is it always about surgery?

Radiomics-Based Prediction of Long-Term Treatment Response of Vestibular Schwannomas Following Stereotactic Radiosurgery.

Stereotactic radiosurgery (SRS) is one of the treatment modalities for vestibular schwannomas (VSs). However, tumor progression can still occur after treatment. Currently, it remains unknown how to predict long-term SRS treatment outcome. This study investigates possible magnetic resonance imaging (MRI)-based predictors of long-term tumor control following SRS. Retrospective cohort study. Tertiary referral center. Analysis was performed on a database containing 735 patients with unilateral VS, treated with SRS between June 2002 and December 2014. Using strict volumetric criteria for long-term tumor control and tumor progression, a total of 85 patients were included for tumor texture analysis. All patients underwent SRS and had at least 2 years of follow-up. Quantitative tumor texture features were extracted from conventional MRI scans. These features were supplied to a machine learning stage to train prediction models. Prediction accuracy, sensitivity, specificity, and area under the receiver operating curve (AUC) are evaluated. Gray-level co-occurrence matrices, which capture statistics from specific MRI tumor texture features, obtained the best prediction scores: 0.77 accuracy, 0.71 sensitivity, 0.83 specificity, and 0.93 AUC. These prediction scores further improved to 0.83, 0.83, 0.82, and 0.99, respectively, for tumors larger than 5 cm. Results of this study show the feasibility of predicting the long-term SRS treatment response of VS tumors on an individual basis, using MRI-based tumor texture features. These results can be exploited for further research into creating a clinical decision support system, facilitating physicians, and patients to select a personalized optimal treatment strategy.

The malignancy among gastric submucosal tumor

The origin and characteristics of most submucosal tumors (SMTs) cannot easily be confirmed by gastrointestinal endoscopy or other radiological examinations. Excluding GISTs, for those other gastric SMTs, most of which are deemed benign, the necessity and timing of intervention has been ignored. Thus, the malignancy of gastric SMTs still remains unknown. In order to summarize the malignancy of these gastric SMTs, we reviewed literatures and analyzed cases of gastric SMTs including heterotopic pancreas, leiomyoma, schwannoma, glomus tumor, hemangioendothelioma, granular cell tumor (GCT), lipoma, hemangiopericytoma, lymphangioma and neurofibroma. In these literatures, there are cases of malignancy among heterotopic pancreas, leiomyoma, schwannoma, glomus tumor, hemangioendothelioma and GCT. As a result, it suggests that although most of gastric SMTs are considered benign, there are still possibilities of malignancy, which requires our attention, even active intervention and long-term follow-up.

New insights into the neurofibroma tumor cells of origin.

Neurofibromatosis type I (NF1) is a debilitating inherited tumor syndrome affecting around 1 in 3000 people. Patients present with a variety of tumors caused by biallelic loss of the tumor suppressor neurofibromin (NF1), a negative regulator of Ras signaling. While the mechanism of tumor formation is similar in the majority of NF1 cases, the clinical spectrum of tumors can vary depending on spatiotemporal loss of heterozygosity of NF1 in cells derived from the neural crest during development. The hallmark lesions that give NF1 its namesake are neurofibromas, which are benign Schwann cell tumors composed of nervous and fibrous tissue. Neurofibromas can be found in the skin (cutaneous neurofibroma) or deeper in body near nerve plexuses (plexiform neurofibroma). While neurofibromas have been known to be Schwann cell tumors for many years, the exact timing and initiating cell has remained elusive. This has led to difficulties in developing animal models and successful therapies for NF1. A culmination of recent genetic studies has finally begun to shed light on the detailed cellular origins of neurofibromatosis. In this review, we will examine the hunt for neurofibroma tumor cells of origin through a historical lens, detailing the genetic systems used to delineate the source of plexiform and cutaneous neurofibromas. Through these novel findings, we can better understand the cellular, temporal, and developmental context during tumor initiation. By leveraging this data, we hope to uncover new therapeutic targets and mechanisms to treat NF1 patients.

Effects of self-designed facial muscle exercise in facial paralysis nursing among patients after acoustic neurinoma surgery

Objective To explore the effects of self-designed facial muscle exercise in facial paralysis nursing among patients after acoustic neurinoma surgery. Methods From May 2018 to February 2019, we selected 90 cerebellopontine angle (CPA) patients after acoustic neurinoma surgery of the Cancer Ward of Neurosurgery Department at a Class Ⅲ Grade A hospital in Beijing. All of the patients were randomly divided into experimental group (n=50) and control group (n=40) . Control group carried out routine facial paralysis management. On the basis of routine nursing, experimental group implemented the self-designed facial muscle exercise directed by researchers from 10: 00 to 11: 00 in the morning and from 16: 00 to 17: 00 in the afternoon. The grades of facial paralysis after facial paralysis were assessed with the House-Brackmann facial nerve grading system, and statistical analysis was used to the recovery effects of facial paralysis and anxiety of patients between two groups. Results A total of 30 days after surgery, the total effective rate of experimental group was higher than that of control group with a statistical difference (P 0.05) . The scores of SAS of experimental group were lower than those of control group 7, 30 and 90 days after surgery with statistical differences (P<0.01) . Conclusions The self-designed facial muscle exercise can promote the recovery of facial paralysis after acoustic neurinoma surgery and improve anxiety of patients. Key words: Rehabilitation nursing; Acoustic neurinoma; Postoperative period; Facial paralysis; Self-designed facial muscle exercise; Anxiety

Clinical application of 3D MRI in diagnosis and treatment of brachial plexus and subclavian artery compression by tumors

Objective To explore the diagnostic advantages and clinical application value of 3D MRI neurovascular fusion technique in brachial plexus with subclavian artery lesions caused by tumor compression. Methods From December 2014 to December 2017, 5 patients were treated, including 2 cases of breast cancer metastasis, 2 cases of schwannoma and 1 case of lung cancer metastasis. The pathological changes of brachial plexus and subclavian artery caused by tumor compression were preliminarily considered by clinical examination, electromyography, ultrasound and CT. All the patients underwent three-dimensional reconstruction using 3D MRI neurovascular fusion technique. The abnormal condition of brachial plexus and subclavian artery was determined according to three-dimensional anatomical model, and the treatment plan was worked out. Results Three-dimensional reconstruction and digital fusion were performed in 5 patients with tumors and anatomical structures of brachial plexus and subclavian artery. The reconstructed images of blood vessels and nerves were well displayed, and the treatment plan was formulated on the basis of these images. There were 4 cases of operation and 1 case of conservative treatment. The intraoperative manifestations of the patients were consistent with the imaging manifestations, and the therapeutic effect reached the expected goal. The patients performed conservative treatment can timely understand the condition and choose other treatment options. Conclusion 3D MRI can clearly and vividly display the structure of the tumors, such as the brachial plexus and the subclavian artery, and provide the imaging basis for diagnosis and treatment. This technique can be further studied and applied. Key words: Brachial plexus; Neoplasms; 3D MRI; Subclavian artery

Vestibular Schwannoma Tumor Size Is Associated With Acute Vestibular Symptoms After Gamma Knife Therapy

To assess how pretreatment vestibular schwannoma (VS) tumor characteristics are associated with vestibular symptoms after gamma knife (GK) surgery. Retrospective chart review of patients undergoing GK treatment for VS at our institution from 2005 to 2018. Academic tertiary referral center. Patients receiving primary GK surgery for vestibular schwannomas with at least 6 months of follow up. Patients with neurofibromatosis 2 or previous surgery were excluded. The presence of posttreatment vestibular symptoms within 6 months after GK. Clinical records were assessed for pretreatment tumor, patient, and treatment characteristics that impacted posttreatment symptoms. All patients received radiation doses between 12 and 13 Gy. Of 115 patients, the average age was 60. Thirty-seven (32%) patients developed vestibular symptoms within 6 months post-GK, and 18 patients were referred for vestibular rehabilitation. Ten of 13 patients undergoing vestibular rehabilitation reported improvement. Overall, 112 patients had tumor measurements. Pretreatment tumors were significantly smaller for patients with acute vestibular symptoms (mean 1.43 cm versus 1.71 cm, p = 0.007). On multivariate analysis, smaller tumor size (p = 0.009, odds ratio [OR] = 0.29, 95% confidence interval [CI] [0.12-0.73]) was significantly associated with vestibular symptoms within 6 months of GK. Patients with tumors less than 1.6 cm were more likely to receive referrals for vestibular rehabilitation within 6 months posttreatment (25% versus 9.4%, p = 0.026, OR = 3.22, 95% CI [1.00, 11.32]). Smaller vestibular schwannomas were significantly associated with higher rates of post-GK vestibular symptoms. Pretreatment tumor size may be used to counsel patients on the likelihood of post-GK vestibular symptoms and vestibular rehabilitation.

Integrated Multi-Omics Characterization of Neurofibromatosis Type 1 Related Peripheral Nerve Sheath Tumors Identifies Two Distinct Malignant Peripheral Nerve Sheath Tumors Subtypes with Sonic Hedgehog or WNT Pathway Activation

Abstract INTRODUCTION Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive Schwann-cell derived sarcomas and the leading cause of mortality in neurofibromatosis Type 1. In many cases, MPNSTs develop through malignant transformation of an underlying neurofibroma (NF). The genomic alterations and molecular pathways driving malignant transformation is not well understood. In this study, we leverage multi-platform genomic and epigenomic profiling of human NFs and MPNSTs to identify targetable molecular pathways that lead to malignant transformation. METHODS Fresh-frozen tumor (N = 108; 19 MPNSTs, 18 premalignant NFs, 37 benign peripheral nerve NFs, and 34 cutaneous NFs) and matched-controls were allocated for NGS platforms including methylation-profiling, RNA, whole exome and ChIP sequencing. In addition, functional validation of identified pathways was performed using CRISPR/cas9 knockout of relevant sonic hedgehog (SHH) and WNT pathway genes in immortalized neurofibroma cell lines. RESULTS Unsupervised consensus clustering of peripheral nerve tumors identified 4 distinct methylation subgroups, with MPNSTs clustering in either Methyl_Grp-2B or Methyl_Grp-3. Transcriptomic analysis of the MPNSTs, identified SHH pathway activation in Methyl_Grp-3 MPNSTs (NES = 1.9952, P &lt; .0001, FDR &lt; 0.001) and WNT pathway activation in Methyl_Grp-2B MPNSTs (NES = 1.7630, P &lt; .0001, FDR = 0.0058). Single sample gene set enrichment analysis demonstrates that there is a strong negative correlation between SHH and WNT pathway activation in MPNSTs (r = −0.78, P = .007). Methyl_Gr-3 MPNSTs harbor more PTCH1 copy number loss (62.5% vs 0%, P &lt; .05) and PTCH1 promoter hypermethylation (mean beta value: 0.2899 vs. 0.06119, P &lt; .05). PTCH1 knockout in immortalized neurofibroma cell lines increased expression of SHH pathway target genes (GLI1, GLI2, and SMO), and increased cellular proliferation and invasiveness. CONCLUSION We found that MPNSTs can be classified into two molecular subgroups driven by SHH or WNT pathway activation. Furthermore, PTCH1 loss is one mechanism that mediates SHH pathway activation. These results suggest a targeted approach should be taken for treating MPNSTs, and SHH and WNT pathway inhibition may be promising avenue for therapeutic development.

Fascicle Sparing Capsular Resections of Atypical Neurofibromas in Neurofibromatosis 1

Abstract INTRODUCTION Neurofibromatosis type 1 (NF1) patients are predisposed to neurofibromas (NF), which can progress to premalignant atypical neurofibromas (ANF) and malignant peripheral nerve sheath tumors (MPNST). Subtotal resection of ANF may prevent metastases and deaths, but local recurrences require reoperation. Here, we assess the surgical morbidity associated with gross total, extracapsular resection of targeted ANF nodules identified via serial volumetric magnetic resonance imaging (MRI) and 18F-FDG-PET imaging. METHODS We retrospectively analyzed the clinical outcomes of 11 NF1 patients following 16 NF surgical resections of 21 tumors at the NIH Clinical Center between 2008 and 2018. Preoperative volumetric growth rates and 18F-FDG-PET SUVMAX of the target lesions were measured and assessed in tandem with postoperative complications, histopathological classification of the resected tumors, and surgical margins through Dunnett's multiple comparison tests and t-tests. RESULTS Preoperatively, 13 of the 14 (93%) sets of serial preoperative MRI scans showed rapid growth ( = 20% increase in volume per year), and 10 of the 11 (91%) 18F-FDG-PET scans indicated increased positron emission tomography (PET) avidity (median SUVMax = 6.45). Gross total, extracapsular resections of the targeted neurofibroma nodules were annotated by the surgeon in all 16 (100%) surgeries, and most surgeries (n = 14, 88%) resulted in no persistent postoperative parent nerve-related complications. SUVMax was significantly greater in the ANF (6.51 ± 0.83, P = .0042) and low grade MPNST (13.8, P = .0001) strata than in the benign NF (1.9) stratum. To date, none of the resected NF have recurred. CONCLUSION This study confirms that the combination of increased 18F-FDG-PET SUVMax, rapid growth, and pain can serve as reliable indicators of atypical transformation and the need for surgical intervention. We also demonstrate the ability to achieve safe, fascicle-sparing gross total, extracapsular resection of ANF using intraoperative nerve stimulation, histological verification, and continued monitoring for tumor recurrence.

Getting the gist of a schwannoma

Getting the gist of a schwannoma

A pilot study of using multiphoton microscopy to diagnose schwannoma

Schwannoma is a kind of slow-growing and rare neoplasm which poses diagnostic challenges owing to its clinical silence at the presentation period. Here, a schwannoma tumor was studied by multiphoton microscopy (MPM). Results indicate that MPM is capable of identifying a schwannoma tumor without the need for labels. Based on the two-photon excited fluorescence signals from cells and blood vessels and second harmonic generation signals from collagens, several significant features for the identification of schwannoma were visualized, including the Antoni A region, Antoni B region, pericellular collagen pattern, hyalinized vessels and hyalinized stroma. These conclusions highlight the potential of MPM taken as a diagnostic method for label-free identification of schwannoma tumors by these histopathologic characteristics.

Laryngeal tumor of neurogenetic origin - a case report and review of the literature

Schwann cell tumors are rare group of benign neoplasms that origin form peripheral nerves. 0,1%-1,5% develops in the larynx causing hoarseness, difficulty with swallowing and dyspnea. Treatment of the choice is surgical resection of the tumor during open type surgery or endoscopic procedure. Chosen surgical technique depends on tumor localization, size observed in clinical examination and imaging. Also, clinical manifestation of the disease is included in decision making process.

ALDH1 - A new immunohistochemical diagnostic marker for Schwann cell-derived tumors.

Although Schwann cell-derived tumors show typical histological features, the broad variety of spindle cell tumors that exist can impede the diagnostic procedure. In this study, we present aldehyde dehydrogenase 1 (ALDH1) as a new, viable diagnostic marker for Schwann cell tumors. Protein expression was examined by immunohistochemistry in schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors (MPNST) as well as in non-neoplastic peripheral nerve sheath specimens. Meningiomas and other spindle cell-like tumors served as control tissue. ALDH1 immunohistochemistry was performed on human FFPE samples. Staining evaluation was performed according to a defined immunoreactive score. All schwannomas and neurofibromas were strongly positive for ALDH1. MPNST were positive too, but with a clear reduction of ALDH1 expression. All non-Schwann-cell-derived tumors showed no immunoreaction. This leads to the conclusion that ALDH1 can serve a as viable diagnostic marker for schwannomas and neurofibromas as it was expressed and detected by IHC in all samples. Furthermore, ALDH1 expression seems to be a sign for differentiation as it diminishes during malignization of Schwann cell tumors. Hence, its expression level provides information about the biological behavior of the tumor.

Tympanic-mastoid and parotid schwannomas of the facial nerve: clinical presentation related to the anatomic site of origin.

To describe the clinical presentation of the facial nerve schwannomas according to the anatomical site of origin. A retrospective study in which the clinical presentation, diagnostic protocol and treatment of facial nerve tumors in adults was evaluated. We found 6 cases, 4 cases of tympanic-mastoid location at the spectrum of its possible clinical presentation: from symptomatic cases with facial paralysis, to an asymptomatic case in the tympanic portion found as intraoperative finding; and also found two cases located at the parotid gland, one with complete facial paralysis and one without facial palsy. For the diagnosis of intratemporal and parotid schwannomas of the facial nerve, a high clinical suspicion is required given its heterogeneous presentation; its clinical course depends on the segment of origin and expansion: more frequently asymptomatic at the tympanic horizontal portion and symptomatic at the mastoid vertical portion. These tumors must be assessed with imaging studies, incisional biopsy is not recommended. The treatment is surgical resection in symptomatic patients with facial paralysis greater than grade III of House-Brackmann, with immediate reconstruction of the nerve.

Evaluation of the quality of life of patients with sporadic vestibular schwannoma

Значне поширення нейровізуалізаційних методів діагностики та збільшення обізнаності лікарів первинної ланки щодо інтракраніальних новоутворень сприяє їх ранній діагностиці. З кожним роком кількість випадків вестибулярних шваном (ВШ), які діагностують на ранніх етапах, прогресивно зростає. Збільшення частки ВШ малого та середнього розміру з невираженими клінічними ознаками є приводом для дискусії щодо вибору методу лікування: динамічне спостереження, радіохірургію чи мікрохірургію? Зробити правильний вибір складно не лише пацієнту, а і досвідченному лікарю. Наведено огляд літератури щодо оцінки якості життя (ЯЖ) у пацієнтів із спорадичними ВШ. Представлено відповідні анкети і шкали. Систематизовано результати авторитетних і високоцитованих досліджень з цього питання. Згідно з результатами більшості досліджень ЯЖ у пацієнтів з ВШ, пухлини малого розміру (<15 мм) підлягають динамічному спостереженню, особливо у разі суб’єктивного задовільного функціонального стану пацієнта. У процедурі вибору методу лікування ВШ необхідна активна участь пацієнта і його родичів. Будь-яке рішення слід приймати, намагаючись знайти баланс між можливими ускладненнями і природним перебігом пухлини. При розгляді мікрохірургічного видалення або радіохірургічного лікування ВШ обов’язково слід поінформувати про ризик появи нового і наростання існуючого неврологічного дефіциту зі зниженням ЯЖ, а також про прогностичні чинники, які на це впливають. У разі застосування радіохірургічного лікування слід також оцінити можливість довгострокового припинення росту пухлини, віддалені негативні ефекти опромінення на функцію черепних нервів і функціональний стан пацієнта, ризик перитуморозного набряку та малігнізації пухлини, спричиненої радіохірургією. Для правильної оцінки оптимальної тактики лікування ВШ необхідна чітка систематизація результатів проведених досліджень з урахуванням усіх прогностичних чинників, які впливають на ЯЖ конкретного хворого. Проблема вибору тактики лікування на основі прогнозування ЯЖ залежно від обраного методу лікування потребує подальшого вивчення.

Microsurgical treatment of cerebrospinal fluid rhinorrhea after operation of vestibular schwannoma due to the opening of internal auditory canal

Objective To investigate the microsurgical treatment of refractory cerebrospinal fluid (CSF) rhinorrhea after operation of vestibular schwannoma due to the opening of internal auditory canal. Methods From January 2012 to May 2018, a total of 249 patients with vestibular schwannoma underwent tumor resection at Neurosurgery Department, Xuanwu Hospital of Capital Medical University. There were 8 (3.2%) cases that developed CSF rhinorrhea after operation. Among them, 5 underwent conservative therapy and CSF leakage disappeared and the remaining 3 (1.2%) cases with refractory CSF leakage received second craniotomy for CSF leakage repair on the 3rd, 9 th and 28 th day after tumor resection respectively. Suboccipital retrosigmoid approach (original incision) was used to repair the defect of posterior wall of internal auditory canal. Fresh muscle granules and glue were used to seal the defect of posterior wall of internal auditory canal. Results Among the 3 patients who underwent surgical repair operation, CSF leakage disappeared immediately in 2 cases and cured one month later in 1 case. Facial nerve function was not affected after the second operation. The assessment based on House-Brackman classification revealed grade 1 in 2 cases and grade 2 in 1 case at discharge. All the 3 patients developed intracranial infection and recovered after anti-infection therapy. Conclusions CSF rhinorrhea after vestibular schwannoma surgery is a relatively common complication. Meticulous sealing of opened air cells in the petrous bone (around the inner auditory canal and mastoid air cells) seems necessary for the prevention and treatment CSF leakage. Key words: Neuroma, acoustic; Cerebrospinal fluid rhinorrhea; Microsurgery; Inner auditory canal