Residual Vestibular Schwannomas Research Articles

Residual Vestibular Schwannomas: Proposed Age-Tumor-Residual (ATR) Staging System to Predict Future Growth.

To assess growth rates of residual vestibular schwannoma after subtotal and near-total surgical resection and establishing staging system for risk of residual tumor growth. Retrospective cohort study. Tertiary referral center. Patients with residual vestibular schwannoma after surgical resection from 2011 to 2023 identified on postoperative MRI defined as near-total resection (NTR, less than 5 mm of remaining tumor), subtotal resection (STR; 5-10 mm) and debulking (>10 mm). Tumor growth of 2 mm or more after subtotal or near-total surgical resection of vestibular schwannoma. A total of 56 patients (54% female; mean, standard deviation [SD] age 51 [17] yr) had residual tumor. Mean preoperative tumor size was 3.0 (1.1) cm, and residual tumors involved both sides with similar frequency (right: 52%). Quantitatively, 29% were NTR, 32% were STR, and 39% were debulking. With an average follow-up of 27 (SD 31) months, tumor growth occurred in 11 (20%), tumor shrinkage occurred in 16 (29%), and tumors were unchanged in 29 (51%) cases. Growing residual tumors were treated with radiation (7 patients) or a second surgical resection (4 patients). Multivariable analysis identified lower patient age, larger preoperative tumor size, and larger residual tumor size in risk of residual growth. A residual VS tumor staging system (Age, Tumor, Residual [ATR]) is proposed with most tumors in stage II (22, 42%) or stage III (23, 44%), whereas 7 (14%) tumors are stage I. Approximately 80% of residual VS are stable or shrink in size. Initial observation is advocated after incomplete resection and long-term follow up is needed. Patient age less than 55 years, larger preoperative tumor size, and larger postoperative residual tumor size appear predictive of residual tumor growth.Level of Evidence: 4.

Surgical results for one-stage VII/VIII schwannoma resection and hemihypoglossal-facial neurorrhaphy

BackgroundThis retrospective study evaluated the outcomes of patients undergoing one-stage resection of VII/VIII schwannomas and hemihypoglossal-facial neurorrhaphy via the translabyrinthine approach (TLA). MethodsThe study encompassed ten consecutive patients with unilateral hearing loss (six women, four men, mean age: 49.5 ± 12.1 years) who underwent surgery. The cohort included two patients with vestibular schwannomas (VSs), four with facial nerve schwannomas (FNSs) (two originating from the geniculate ganglion of the facial nerve and two from the cerebellopontine angle), one with VS regrowth, and three with residual VSs. Preoperative facial nerve function, assessed using the House–Brackmann (HB) scale, was Grade V in one and Grade VI in nine patients. The mean preoperative duration of facial paralysis was 7.5 ± 6.9 months. ResultsAll patients underwent gross total resection. Postoperatively, one patient experienced cerebrospinal fluid leaks, which were successfully managed with lumbar drains and surgical revisions. At follow-up, facial nerve function improved in all patients: HB Grade V to III in one, HB Grade VI to III in one, HB Grade VI to IV in seven, and Grade VI to V in one. No tumor recurrence was observed during the follow-up period (mean duration: 16.6 ± 9.3 months), and no patient had hemilingual atrophy. ConclusionThe TLA for one-stage resection of VII/VIII schwannomas and facial nerve reconstruction is effective in treating both regrowth and residual VSs and FNSs in the cerebellopontine angle or petrosal bone in patients with severe preoperative facial palsy. This technique facilitates simultaneous tumor removal and nerve anastomosis, thereby reducing the need for multiple surgical interventions in patients with hearing loss and compromised facial nerve function.

Distinct immune signature predicts progression of vestibular schwannoma and unveils a possible viral etiology

BackgroundThe management of sub-totally resected sporadic vestibular schwannoma (VS) may include observation, re-resection or irradiation. Identifying the optimal choice can be difficult due to the disease’s variable progression rate.We aimed to define an immune signature and associated transcriptomic fingerprint characteristic of rapidly-progressing VS to elucidate the underpinnings of rapidly progressing VS and identify a prognostic model for determining rate of progression.MethodsWe used multiplex immunofluorescence to characterize the immune microenvironment in 17 patients with sporadic VS treated with subtotal surgical resection alone. Transcriptomic analysis revealed differentially-expressed genes and dysregulated pathways when comparing rapidly-progressing VS to slowly or non-progressing VS.ResultsRapidly progressing VS was distinctly enriched in CD4+, CD8+, CD20+, and CD68+ immune cells. RNA data indicated the upregulation of anti-viral innate immune response and T-cell senescence. K − Top Scoring Pair analysis identified 6 pairs of immunosenescence-related genes (CD38-KDR, CD22-STAT5A, APCS-CXCR6, MADCAM1-MPL, IL6-NFATC3, and CXCL2-TLR6) that had high sensitivity (100%) and specificity (78%) for identifying rapid VS progression.ConclusionRapid progression of residual vestibular schwannoma following subtotal surgical resection has an underlying immune etiology that may be virally originating; and despite an abundant adaptive immune response, T-cell immunosenescence may be associated with rapid progression of VS. These findings provide a rationale for clinical trials evaluating immunotherapy in patients with rapidly progressing VS.

Evaluating growth trends of residual sporadic vestibular schwannomas: a systematic review and meta-analysis.

Gross total resection remains the gold-standard approach for vestibular schwannomas (VS) when surgery is indicated. In select cases, incomplete resection (IR) becomes a desired alternative to preserve the facial nerve function and the patient's quality of life. While a lot of earlier studies described incompletely resected sporadic VSs as dormant, more recent studies reported a higher growth rate following IR, therefore an evaluation of the residual VS growth rates could have important implications for the follow-up treatment protocols and provide relevant information for neurosurgeons, neuro-otologists, neuropathologists, and radiologists. Although prognostic factors predicting preoperative VS growth have been previously investigated, these factors have not been investigated following IR. Our review aims to examine the growth rate of residual sporadic VS following IR and to examine variables associated with the regrowth of residual VS. The review was conducted in accordance with the PRISMA guidelines. Six databases (MEDLINE (Ovid), Embase (Ovid), CINAHL Plus (EBSCO), Cochrane Central Register of Controlled Trials (CENTRAL), WHO International Clinical Trials Registry Platform and UK Clinical Trials Gateway (WHO ICTRP) were searched. Full-text articles analysing growth rates in at least ten patients who had residual VS after IR were assessed. We conducted a meta-analysis using a random-effects model via RevMan. 14 studies totalling 849 patients were included in the analysis. The mean planimetric growth rate was 1.57mm/year (range 0.16-3.81mm/year). The mean volumetric growth rate was 281.725 mm3/year (range 17.9-530.0 mm3/year). Age, sex, pre-operative tumour size/volume, cystic tumour sub-type, MIB-1 index, and intracanalicular tumour location were not associated with residual growth. Residual tumour size/volume was statistically significant to growth (OR = 0.65, 95% CI 0.47-0.90, p = 0.01). Radiological re-growth occurred in an average of 26.6% of cases (range 0-54.5%). From our analysis, only the residual tumour volume/size was associated with residual VS growth. Therefore, close postoperative surveillance for the first year, followed by an annual MRI scan for at least 5years, and subsequently extended interval surveillance remains of utmost importance to monitor disease progression and provide timely surgical and adjuvant interventions. Our study shows that future work should be aimed at molecular and histological characteristics of residual VSs to aid prognostic understanding of growth.

Marking of the proximal facial nerve stump for delayed repair after vestibular schwannoma removal

Objective: To investigate whether marking the facial nerve stump during surgery permits facial nerve reconstruction to be performed successfully at later surgical intervention.
 Case report: The patient was operated for a large residual vestibular schwannoma via the retrosigmoid approach and the facial nerve was injured during tumor removal. A metal clip was placed on a facial nerve stump to permit localization and identification at a later time. One month after the first operation nerve repair employing a sural nerve graft from the cerebellopontine angle to the mastoid portion of the facial nerve was performed through the translabyrinthine approach.
 Conclusion: Follow-up of facial function was carried up for more than two years. The patient achieved very good functional results, confirming that end-to-end facial nerve repair with an interposition graft with positive outcome can be successfully performed as a delayed procedure.

Optimal Volume of the Residual Tumor to Predict Long-term Tumor Control Using Stereotactic Radiosurgery after Facial Nerve-preserving Surgery for Vestibular Schwannomas.

BackgroundIntended subtotal resection (STR) followed by adjuvant gamma knife radiosurgery (GKRS) has emerged as an effective treatment option for facial nerve (FN) preservation in vestibular schwannomas (VSs). This study aimed to identify the optimal cut-off volume of residual VS to predict favorable outcomes in terms of both tumor control and FN preservation.MethodsThis retrospective study assessed the patients who underwent adjuvant GKRS for residual VS after microsurgery. A total of 68 patients who had been followed up for ≥ 24 months after GKRS were included. Tumor progression was defined as an increase in tumor volume (TV) of ≥ 20%. House-Brackmann grades I and II were considered to indicate good FN function.ResultsThe median residual TV was 2.5 cm3 (range: 0.3–27.4). The median follow-up period after the first adjuvant GKRS was 64 months (range: 25.7–152.4). Eight (12%) patients showed tumor progression. In multivariate analyses, residual TV was associated with tumor progression (P = 0.003; hazard ratio [HR], 1.229; 95% confidence interval [CI], 1.075–1.405). A residual TV of 6.4 cm3 was identified as the cut-off volume for showing the greatest difference in progression-free survival (PFS). The 5-year PFS rates in the group with residual TVs of < 6.4 cm3 (54 patients) and that with residual TVs of ≥ 6.4 cm3 (14 patients) were 93.3% and 69.3%, respectively (P = 0.014). A good FN outcome was achieved in 57 (84%) patients. Residual TV was not associated with good FN function during the immediate postoperative period (P = 0.695; odds ratio [OR], 1.024; 95% CI, 0.908–1.156) or at the last follow-up (P = 0.755; OR, 0.980; 95% CI, 0.866–1.110).ConclusionIn this study, residual TV was associated with tumor progression in VS after adjuvant GKRS following STR. As preservation of FN function is not correlated with the extent of resection, optimal volume reduction is imperative to achieve long-term tumor control. Our findings will help surgeons predict the prognosis of residual VS after FN-preserving surgery.

Long-term outcomes of patients with primary or residual vestibular schwannoma treated with LINAC-based stereotactic radiosurgery: a single-centre experience

AbstractAim:Vestibular schwannomas (VS) are benign slow-growing tumours treated either with microsurgery or stereotactic radiosurgery (SRS) or both. The aim of this study was to correlate the outcome factors—tumour control and adverse factors—facial nerve function and hearing loss with patient and treatment factors.Materials and methods:A retrospective review of the records of 98 patients with 99 VS treated from June 2007 to June 2014, all patients receiving Linear Accelerator (LINAC)-based SRS.Results:Median follow-up period was 5·6 years (range: 1–12 years). The response to treatment was stable disease in 37 (37·4%), regression in 46 (46·5%), asymptomatic minimal progression in 9 (9·1%) and symptomatic progression in 5 (5%) and unknown in 2 (2%) patients. There was no evidence of SRS induced tissue damage on magnetic resonance scans for any. Hearing preservation rate after SRS was 92%. The patients who developed worsening of facial function were predominantly in the cohort that had prior surgery.Findings:SRS is an effective modality to treat VS lesser than 3 cm in size. Tumour control rate was 95% with a median follow-up period of 5·6 years. The complication rates were 8% each for facial function worsening and worsening of hearing. Prior surgery was a statistically significant factor that affected facial nerve function deterioration.

MRI Monitoring of Residual Vestibular Schwannomas: Modeling and Predictors of Growth.

The aim was to model residual Vestibular Schwannoma (VS) over time to identify prognostic factors of postsurgical growth. Multicenter retrospective study. Tertiary referral centers. A group of 135 patients who underwent incomplete resection for VS between January 2010 and December 2018. On magnetic resonance imaging (MRI) examinations at baseline (1 year after surgery), patients included were divided into two groups: near-total resection (NTR, <25 mm × 2 mm) and subtotal resection (STR, greater volume). Monitoring of residual VS volume. 3D volumetric segmentation of residual tumors was performed on every MRI examination at baseline and during follow-up to model volume changes over time using the Lambda-Mu-Sigma method. The study followed-up 127 patients (median age: 56 yr) over a median follow-up of 39 months. Most VS residues (76.7%; 89/116) showed no growth at 5 years. Only 27 (23.3%) residues showed signs of regrowth (increase in volume >0.05 cm). The extent of resection is a predictor of tumor growth (odds ratio [OR] = 4.85; for STR over NTR; p = 0.003), but the growth rate was significantly different between STR and NTR residues (p < 0.001). At first, over 2 years after surgery, STR residues decreased (-1.0% volume per year), whereas NTR ones grew (+8% per year). Then, both residues showed sign of regrowth. Postoperative recommendations should now include the natural history of VS residue after resection: even though the growth rate differs between STR and NTR residues, most VS residues showed no growth.

Minimal Effect of Bevacizumab Treatment on Residual Vestibular Schwannomas after Partial Resection in Young Neurofibromatosis Type 2 Patients.

Hearing-preserving partial resection of neurofibromatosis type 2 (NF2) associated vestibular schwannomas (VS) is a preferred treatment strategy, particularly for children and adolescents. However, the residual tumors do grow and lead at some point to continued hearing deterioration. An adjuvant bevacizumab treatment may provide an option for slowing down this process. In this retrospective study, we reviewed tumor volume and hearing data of 16 operated VS in nine patients younger than 30 years over a period of 63 to 142 months. All these patients had one or more bevacizumab treatment periods and most of them had a non-treatment period after surgery. Four different patterns of growth were observed for the residual tumors: (1) growth in the non-treatment periods, which slowed down in the treatment periods; (2) growth slowed down in one but not in another on-period; (3) unaffected growth; (4) no or minimal growth regardless of the treatment. Neither radiological regression of tumor volume nor hearing improvement were observed in the treatment periods. Accelerated hearing deterioration was observed in several non-treatment periods, but also in some treatment periods. No straightforward correlation can be drawn between tumor growth and hearing scores. Tumor growth and worsening of hearing between two measurement points were slightly less in the treatment periods; however, the differences were not significant, because variations were large. In conclusion, our comprehensive follow-up on 16 VS in nine NF2 patients did show heterogenous effects of bevacizumab on small residual vestibular schwannomas after surgery both regarding tumor size and hearing preservation. Thus, smaller and slower growing tumor residuals seem to behave differently to bevacizumab than reported for not-operated faster growing VS.

Gamma Knife Radiosurgery for Post-Operative Vestibulocochlear Schwannomas

Background: The discovery of Schwann cells as the oncologic cells led to the recommendation by a consensus meeting in 1992 to use the term vestibular schwannoma. In the literature, the terms acoustic neurinoma, acoustic neuroma, and vestibular schwannoma are used interchangeably. Objective: Evaluation of the outcome of the management of post-operative recurrent or residual vestibular schwannomas by using gamma knife radiosurgery (GKRS). Patients and Methods: In this retrospective descriptive case series study during the year of 2018 on twenty (20) consecutive cases at the International Medical Center (IMC) with residual or recurrent post-operative vestibulocochlear schwannomas (VS) whom underwent gamma knife stereotactic radiosurgery (SRS). Clinical & radiological follow up done for a period of 6 months minimum up to 3 years. Results: After GKRS, it was shown that the cerebellar ataxia improved in 7 cases (100%). 5th cranial nerve affection improved in 6 cases (100%). 7th cranial nerve affection improved in 5 cases (100%). Hearing affection deterioration occurred in 4 cases (20%), 16 cases had stationary course (80%), Local tumor control in 90% of patients & Regrowth of tumor in 10% of patients. Conclusion: GKRS is the best choice in small size VSs less than 3 cm in maximum diameter X, Y, Z either prior surgery was done or not due to its advantageous preservation of all cranial nerves as they can withstand the prescribed SRS dose for VSs.

Local Tumor Control and Clinical Symptoms After Gamma Knife Radiosurgery for Residual and Recurrent Vestibular Schwannomas

The use of Gamma Knife radiosurgery (GKRS) for recurrent or residual vestibular schwannoma (VS) after microsurgery (MS) has been investigated in several retrospective studies. The purpose of this study was to identify potential risk factors for both neurologic deterioration and tumor progression after GKRS for previously operated VSs in a prospective setting. Patients who underwent GKRS for previously operated and histopathologically confirmed VS between 1998 and 2015 were prospectively followed-up. Risk factors for therapy side effects and predictors for tumor control were investigated in uni- and multivariate analyses. A total of 160 individuals with a median age of 55 years were included. Median tumor volume prior to GKRS was 1.40 cm3 (range, 0.06-35.80 cm3). After a median follow-up of 36 months, hearing and facial nerve function were serviceable (modified Gardner-Robertson and House-Brackmann grades I and II) in 7 (5%) and 82 (55%) patients, respectively. Deterioration to a nonserviceable facial nerve function after GKRS was found in 3% (3/89) and tended to increase with rising tumor volume (odds ratio, 1.65 per cm3; 95% confidence interval, 1.00-2.71; P= 0.051). Median tumor volume prior to GKRS was higher in patients with radiologic (P= 0.020) or clinical tumor progression (P<0.001). Critical tumor volume prior to GKRS to predict clinical and radiologic tumor progression was 1.30 cm3 (P< 0.001) and 3.30 cm3 (P= 0.019), respectively. However, in multivariate analyses, none of the analyzed variables were found to independently predict tumor progression. Intended submaximal resection followed by GKRS is a viable treatment for VS. Because tumor remnant size after MS is an important predictor for recurrence after adjuvant GKRS, both brainstem and cerebellar decompression and maximal safely achievable resection should remain major goals of microsurgery.

Growth Patterns of Residual Tumor in Preoperatively Growing Vestibular Schwannomas.

Objectives To analyze growth of residual vestibular schwannoma (VS) following incomplete tumor resection and determine the influence of residual location and size. Design Retrospective case note and scan review. Setting Tertiary skull base unit. Participants Patients with residual tumor following primary surgery for medium and large unilateral growing vestibular schwanomas between 2006 and 2009. Main Outcome Measures Location of residual VS and post-operative growth, comparing those with more (>5%) or less than 5% of tumor residual (<5%). Results Fifty-two patients had visible residual tumor left behind at surgery. Twenty had < 5% and 32 had > 5% residual. The residual growth rates were 38% overall, 20% in < 5%, and 50% in > 5% residuals. There was no significant difference in growth rates at different residual locations. Median follow-up was 6.4 years. Conclusions There is a greater risk of regrowth of residuals > 5%. All positions of residual tumor can regrow, and the preoperative tumor size plays a role in this. Further data is needed to confirm if residual tumor in the fundus is less likely to grow.

322 Rate of Residual Tumor Growth After Primary Subtotal Resection (STR) and the Role of Upfront Versus Salvage Stereotactic Radiosurgery (SRS) for Sporadic Vestibular Schwannomas

Abstract INTRODUCTION Maximal safe resection is an optimal surgical strategy for moderate-to-large vestibular schwannomas, however data on the long-term outcomes of residual tumor after STR is lacking. The goal of this study was to review our rates of residual tumor growth, and the control rates of salvage versus upfront stereotactic radiosurgery (SRS). METHODS This retrospective single-institution study included all sporadic vestibular schwannomas treated primarily with STR at our institution from 2002 2015. The primary outcome was tumor growth requiring salvage treatment, and response to salvage treatment (surgery or SRS). Patients treated with upfront SRS after surgery were analyzed separately. RESULTS &gt;295 patients underwent primary surgery for a vestibular schwannoma between 2002 - 2015, including 140 STRs. 49 cases with &lt;1 year follow-up were excluded. 17 cases received upfront SRS after surgery (12 Gamma Knife, 12Gy; 5 CyberKnife, 25Gy in 5 fractions), with 2 failures requiring salvage surgery at 1.6 and 2.6 years (88% control rate at 1.8 years). Seventy-four residual tumors were managed with observation after STR. 57 (77%) remained stable at a median 4.1 years. 17 tumors (23%) progressed, requiring salvage treatment at a median of 2.8 years. Eleven received Gamma Knife (12.5 Gy) with a 100% control rate 2.3 years after SRS. One received Cyber Knife (18Gy, 3 fractions), ultimately requiring repeat surgery 3 years later. 4 residual tumors received salvage surgery at a median interval of 5 years after STR, and one was lost to follow-up. The control rate of salvage SRS was 92% at 2.3 years median follow-up. CONCLUSION A majority (77%) of residual vestibular schwannomas remained stable after a primary STR. Both upfront and salvage SRS had good control rates (∼90%) in our series. Further study is needed to define the role of upfront versus salvage SRS after a primary STR.

Gamma Knife Radiosurgery for Residual and Recurrent Vestibular Schwannomas After Previous Surgery: Clinical Results in a Series of 90 Patients and Review of the Literature

Complete removal of vestibular schwannomas (VS) is not always achievable without any risk of disabling postoperative complications, especially in terms of facial nerve function. Moreover, even after gross total removal, a relevant rate of recurrence has been reported. The aim of this study is to validate Gamma Knife radiosurgery (GKRS) as an effective strategy to treat tumor regrowth after previous surgery. Ninety patients treated with GKRS for VS after previous microsurgery were included in the present study. GKRS was performed at a median of 31 months (range, 4-174 months) postoperatively. Mean tumor volume was 3.35 cm3 (median, 2.5 cm3; range, 0.027-13 cm3) and median marginal dose was 13 Gy. At a mean follow-up of 77.2 months, tumor control was achieved in 90% of patients: 2 patients underwent repeated GKRS, and 7 patients underwent further microsurgery. Tumor shrinkage at last follow-up was recorded in 80.3% of cases. The complication rate was low and many consisted of a transient worsening of preexisting symptoms. The overall incidence of persisting facial nerve deficit and trigeminal nerve impairment was, in both cases, 3.3%. Two of 5 patients (40%) preserved functional hearing at last follow-up. One patient (1.1%) underwent ventriculoperitoneal shunting 12 months after GKRS. GKRS is a safe and effective treatment for growing residual and recurrent VSs, with tumor control obtained in 90% of cases and a low morbidity rate. Moreover, the possibility of treating patients with major medical comorbidities constitutes a significant advantage over repeated surgery.

Where is it safe to leave residual Vestibular Schwannoma during surgery?

Where is it safe to leave residual Vestibular Schwannoma during surgery?

Residual tumour after vestibular schwannoma surgery

To evaluate residual tumour occurrence after vestibular schwannoma surgery, based on intra-operative registration and magnetic resonance imaging one year post-operatively. Patients undergoing translabyrinthine surgery for vestibular schwannoma in Denmark between 1976 and 2008 were registered in a national database covering 5.5 million inhabitants. Translabyrinthine surgery was undertaken on 1143 patients. Of these, 978 had total, 140 near-total and 25 subtotal tumour excision, as assessed intra-operatively by the surgeon. One year after surgery, 65 per cent of small tumour remnants and 11 per cent of large tumour remnants were not visible on magnetic resonance imaging. The mean pre-operative size was significantly smaller for totally excised tumours, compared with near-totally and subtotally excised tumours. Revision surgery was performed for 14 patients (1.2 per cent), of whom 2 had received total, 5 near-total and 6 subtotal excisions initially. Most residual tumours disappear spontaneously, probably due to devascularisation. Few patients with a small residual vestibular schwannoma will require revision surgery or secondary radiotherapy.

Management of large vestibular schwannoma. Part I. Planned subtotal resection followed by Gamma Knife surgery: radiological and clinical aspects

In large vestibular schwannoma (VS), microsurgery is the main treatment option, and complete resection is considered the primary goal. However, previous studies have documented suboptimal facial nerve outcomes in patients who undergo complete resection of large VSs. Subtotal resection is likely to reduce the risk of facial nerve injury but increases the risk of lesion regrowth. Gamma Knife surgery (GKS) can be performed to achieve long-term growth control of residual VS after incomplete resection. In this study the authors report on the results in patients treated using planned subtotal resection followed by GKS with special attention to volumetric growth, control rate, and symptoms. Fifty consecutive patients who underwent the combined treatment strategy of subtotal microsurgical removal and GKS for large VSs between 2002 and 2009 were retrospectively analyzed. Patients with neurofibromatosis Type 2 were excluded. Patient charts were reviewed for clinical symptoms. Audiograms were evaluated to classify hearing pre- and postoperatively. Preoperative and follow-up contrast-enhanced T1-weighted MR images were analyzed using volume-measuring software. Surgery was performed via a translabyrinthine (25 patients) or retrosigmoid (25 patients) approach. The median follow-up was 33.8 months. Clinical control was achieved in 92% of the cases and radiological control in 90%. One year after radiosurgery, facial nerve function was good (House-Brackmann Grade I or II) in 94% of the patients. One of the two patients who underwent surgery to preserve hearing maintained serviceable hearing after resection followed by GKS. Considering the good tumor growth control and facial nerve function preservation as well as the possibility of preserving serviceable hearing and the low number of complications, subtotal resection followed by GKS can be the treatment option of choice for large VSs.

Unique case of malignant transformation of a vestibular schwannoma after fractionated radiotherapy

ObjectiveMalignant transformation of vestibular schwannoma is considered a rare clinical entity. Radiotherapy, as a treatment option for vestibular schwannoma, is regarded as a potential risk factor for secondary malignancy. Recently, radiotherapy with dose fractionation has been proposed, intended to diminish the risk of radiation-induced neuropathy. Case PresentationThe aim of the present study is to report the first case, to the best of our knowledge, of malignant transformation of a residual vestibular schwannoma 19 years after fractionated radiotherapy, describing its characteristics with regard to those previously reported in the literature. ConclusionsThe main purpose of the present work is to state that the knowledge of the iatrogenic potential pitfalls of any technique of radiotherapy in clinical oncology is becoming a necessity. Finally, our report demonstrates that the irradiated patients must be monitored for life because a secondary malignancy may appear after a very long delay.

Treatment of Large and Giant Residual and Recurrent Vestibular Schwannomas

Treatment of Large and Giant Residual and Recurrent Vestibular Schwannomas

Evaluation of tumour response after gamma knife radiosurgery for residual vestibular schwannomas based on MRI morphological features

Objective:To evaluate tumour response after gamma knife (GK) radiosurgery for residual vestibular schwannoma (VS) based on MRI morphological features.Methods:Sixty-one patients with histopathologically confirmed VS underwent GK radiosurgery with marginal tumour...