Temporal Bone Adenoma: A Comprehensive Analysis of Clinical Aspects and Surgical Outcome on a Very Rare Entity.

Objective The aim of this study is to present our experience in dealing with middle ear adenomas (MEAs), very rare tumors of the middle ear. Methods The medical notes of individuals with MEAs treated in tertiary referral; academic settings were retrospectively reviewed. We recorded the presenting symptoms, imaging findings, and pathology results. We additionally examined our surgical outcomes, follow-up period, recurrence, and morbidity. Results We identified four patients with MEAs: two males and two females with an average age of 36.25 years (range = 27-51 years). Despite the detailed imaging studies, including computed tomography and magnetic resonance imaging with intravenous contrast administration, a biopsy was essential in setting the diagnosis. Total surgical resection was achieved in all patients without any recurrence over an average of 6 years (range = 3-10 years). Complete ipsilateral deafness was the commonest surgical morbidity due to footplate infiltration by the tumor. Conclusion Total surgical resection is the treatment of choice in MEAs to minimize the risk for recurrence; this can come with morbidity, mostly sensorineural deafness. Given the very limited literature, long-term follow-up is recommended.

Imaging Post Stereotactic Radiosurgery for Vestibular Schwannomas-When Should We Scan?

OBJECTIVE: To identify the optimal time for imaging following stereotactic radiosurgery (SRS) in patients with vestibular schwannomas (VS). STUDY DESIGN: Retrospective case series. SETTING: Tertiary, university center. PATIENTS: Patients with VS treated with SRS. INTERVENTIONS: Pre- and post-SRS surveillance with magnetic resonance imaging (MRI); patients should have at least two pre- and two post-SRS scans available to be included. MAIN OUTCOME MEASURES: Patient demographics, tumor size, and growth per month ratio pre- and post-SRS and time interval between serial MRI. RESULTS: Forty-two patients fulfilled the inclusion criteria. The average tumor size before the treatment was 16.9 mm (range, 10-28 mm) while 2 years posttreatment it was 16 mm (range, 7-25 mm) (p = 0.5). Average time of the first MRI post-SRS was 11 months (range, 5-14) with an average change in tumor size at that time of +0.53 mm (range, -5-8). Average time to second MRI was 22.3 months (range, 12-33) with an average change in tumor size at second scan of -1.14 (range, -5-2) mm (p = 0.117). The average growth/mo ratio before SRS was 0.26 mm/mo (range, 0-1), while post-SRS 0.05 mm/mo (range, -0.3-0.5) and -0.16 mm/mo (range, -18-0.25) at the time of the first and second scan, respectively (p < 0.001). CONCLUSIONS: Given the initial increase in size following SRS, unless clinically indicated, MRI post-SRS at less than 1 year has no clinical value. The growth per month ratio provides more meaningful values for response to treatment than tumor size measurements.

Intratympanic Gentamicin Versus Labyrinthectomy: Inner Ear Sensitivity to Gentamicin and Impact on the Contralateral Labyrinth.

OBJECTIVES: To investigate the impact of labyrinthectomy and intratympanic (IT) gentamicin injections on the contralateral labyrinth, we also assessed the response of each individual semicircular canal to each IT gentamicin application. METHODS: We performed a pilot observational study on tertiary, referral, academic settings. Thirteen patients with unilateral vestibular pathology were organized into two groups, group I (seven patients) receiving IT gentamicin and group II undergoing labyrinthectomy (six patients). All patients underwent six-canal video-head-impulse test in predetermined time intervals. Patients receiving gentamicin were additionally tested 3 to 5 days after every sequential injection, until all ipsilateral canals were ablated, to determine the order of response to gentamicin. We recorded the vestibular-ocular reflex gains and the presence of covert/overt saccades for each canal. RESULTS: The posttreatment ipsilateral gains were abnormal. No patient from the gentamicin group developed abnormal contralateral responses, while patients undergoing labyrinthectomy had abnormal contralateral responses from at least one canal, even several months posttreatment. Finally, the lateral semicircular canal was the first one to be affected by IT gentamicin followed by the posterior canal: the superior canal was ablated last. CONCLUSION: In our study, labyrinthectomy had an impact on the responses recorded from the contralateral ear, while IT gentamicin ablated the ipsilateral labyrinthine function without affecting the contralateral responses, possibly because of a milder, more gradual impact. We also show for the first time the order that IT gentamicin application affects the semicircular canals, with the lateral being the first to be affected.

Spontaneous Vestibular Schwannoma Regression: A Case-Control Study.

OBJECTIVE: To explore the nature of spontaneously regressing vestibular schwannomas (VS) and identify possible predictive factors for such behavior. STUDY DESIGN: Retrospective case control study. SETTING: Tertiary referral center, university teaching hospital. PATIENTS: Patients with sporadic VS demonstrating spontaneous regression compared with a control group of patients with growing VS. INTERVENTIONS: Review of serial magnetic resonance imaging of the internal auditory meatus (MRI IAM) and case notes and direct comparison of possible related factors between the two groups using univariate analysis. MAIN OUTCOME MEASURES: Presenting symptoms, VS size and consistency, patients' age and sex, tumor laterality and location, and the neutrophil-to-lymphocyte ratio between the two groups. RESULTS: Of the 540 patients on the database 28 (5.2%) showed spontaneous regression with a mean follow-up of 122 months. Mean absolute and relative regression was 3.9 mm and 25.7%, respectively. 60% of tumors showed gradual regression while 25% showed growth followed by regression. Regressing VS had a significantly larger size than the control group; while the regressing tumors were located further from the fundus than the control group. The remaining examined factors did not reach a statistical level of significance. CONCLUSION: This is, to our knowledge, the first study comparing a cohort of regressing tumors with a control group of growing VS. The finding that the location of tumors around the porous, is more common in regressing VS has implications for patients' counselling.

Audiological Outcomes in Growing Vestibular Schwannomas Managed Either Conservatively, or With Stereotactic Radiosurgery.

OBJECTIVE: Recent studies have suggested good hearing preservation following stereotactic radiosurgery (STRS) in patients with vestibular schwannomas (VS). This study aims to assess audiological outcomes in patients with growing VS treated either with STRS, or managed conservatively. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Out of 540 patients with VS, 69 patients with growing VS fulfilled the inclusion criteria; 24 treated conservatively and 45 with STRS. VS were considered growing if demonstrating more than 15% tumor volume increase during 1 year of watchful waiting. INTERVENTION: American Association of Otolaryngology-Head and Neck Surgery (AAOHNS) hearing threshold (dB averaged over 500-3000 Hz) deterioration and Gardner-Robertson class deterioration over time were used as the primary outcome measures. Rate of progression to loss of functional hearing (Gardner-Robertson class I-II) was also determined between cohorts. RESULTS: Mean follow-up was similar between treatment cohorts (STRS = 69.6 mo, conservative management = 71.7 mo). There was no significant difference in AAOHNS deterioration (t = 1.05, df = 53, p = 0.301) or Gardner-Robertson deterioration (χ = 0.47, df = 1, p = 0.492) between cohorts. Furthermore, rate of progression to loss of functional hearing was similar between cohorts (Hazard ratio = 0.704, 95% CI 0.287-1.728, p = 0.44). In STRS patients, AAOHNS deterioration was greater in those with lower AAOHNS thresholds at diagnosis (t = -2.683, df = 28, p = 0.0121). Similarly, Gardner-Robertson deterioration was significantly more likely in STRS patients with functional hearing (Gardner-Robertson class I-II) (Adjusted odds ratio = 32.14, 95% CI 3.15-328, p = 0.0034). CONCLUSIONS: STRS results in similar audiological outcomes compared with patients managed conservatively; Consequently, STRS given to patients with VS to preserve hearing is not justified. In contrast to recent studies, patients with preserved hearing at diagnosis have significantly greater audiological deterioration when undergoing STRS.

Geographic distribution of vestibular schwannomas in West Scotland between 2000-2015.

BACKGROUND: Although the natural history of vestibular schwannomas (VS) has been previously studied, few studies have investigated associated epidemiological factors, primarily because of the lack of large available cohorts. OBJECTIVE: The objective of this study was to perform a multi-scale geographical analysis of the period prevalence of VS in West Scotland from 2000 to 2015. METHODS: Adults diagnosed with sporadic VS were identified through the National Health Services of West Scotland database and geocoded to the unit postcode. To assess whether the cohort of VS cases could be pooled into a period prevalence measure, the locations of VS cases were analyzed by sex using Cross-L and Difference-K functions. VS period prevalence was examined at two aggregate spatial scales: the postcode district and a coarser scale of NHS Health Boards. The spatial structure of period prevalence within each level of spatial aggregation was measured using univariate global and local Moran's I. Bivariate local Moran's I was used to examine the between-scale variability in period prevalence from the postcode district level to the NHS Health Boards levels. Prior to spatial autocorrelation analyses, the period prevalence at the postcode district was tested for stratified spatial heterogeneity within the NHS Health Boards using Wang's q-Statistic. RESULTS: A total of 512 sporadic VS were identified in a population of over 3.1 million. Between 2000 and 2015, VS period prevalence was highest within the NHS Health Boards of Greater Glasgow and Clyde, Ayrshire and Arran and the Western Isles. However, at the NHS scale, period prevalence exhibited no spatial autocorrelation globally or locally. At the district scale, Highland exhibited the most unusual local spatial autocorrelation. Bivariate local Moran's I results indicated general stability of period prevalence across the postcode district to Health Boards scales. However, locally, some postcode districts in Greater Glasgow and Clyde, Ayrshire and Arran exhibited unusually low district to zone spatial autocorrelation in period prevalence, as did the southern parts of the Western Isles. Some unusually high period prevalence values between the postcode district to Health Board scale were found in Tayside, Forth Valley and Dumfries and Galloway. CONCLUSION: Geographic variability in VS in West Scotland was identified in this patient population, showing that there are areas, even remote, with unusually high or low period prevalence. This can be partially attributed to links between primary and tertiary care. Potential genetic or environmental risk factors that may contribute to geographic variation in this disease within Scotland are also a possibility but require further investigation.

Delayed Vestibular Schwannoma Regrowth Following Shrinkage After Stereotactic Radiosurgery: Implication for Life-Long Surveillance.

OBJECTIVE: To enhance understanding of the behavior of vestibular schwannomas (VS) after stereotactic radiosurgery (SRS), including the potential for late tumor regrowth, and the need for lifelong radiological and clinical surveillance. PATIENTS: From a total of 540 patients with VS and out of 95 patients receiving SRS for their growing VS, the cases of two women patients aged 58 and 59 years with medium sized, growing VS are presented. INTERVENTION: Both patients were treated with SRS. Following treatment, both patients had close clinical follow-up and serial magnetic resonance imaging (MRI). MAIN OUTCOME MEASURES: Post-SRS clinical assessment and serial MRI to determine VS size and respond to treatment. RESULTS: Close clinical follow-up after SRS identified no change in symptoms in one patient; the other developed ipsilateral facial nerve twitching without weakness. Serial MRI identified that in both patients, VS that had initially decreased in size following SRS, exhibited significant late regrowth after a 3-year period, reaching the pretreatment size. CONCLUSIONS: This is the first report of late vestibular schwannoma regrowth following a period of significant shrinkage after SRS. Potential reason may be the presence of living cells within the tumor; the possibility of malignant transformation should also be taken into account. Following SRS, patients with VS warrant lifelong radiological and clinical surveillance, even following good response, as there seems to be a small chance of initial regression followed by further growth. Microsurgery for tumor removal and histological diagnosis is indicated in such cases.

Neutrophil to Lymphocyte Ratio as a Predictive Marker of Vestibular Schwannoma Growth.

OBJECTIVE: To examine the predictive value of neutrophil to lymphocyte ratio (NLR) for vestibular schwannoma (VS) growth. STUDY DESIGN: Retrospective case-control study. SETTING: Tertiary, referral center. PATIENTS: Patients with sporadic VS and available NLR obtained within 1 year from the diagnosis were divided into two groups with growing or non-growing tumor. Patients with known conditions affecting NLR were excluded. INTERVENTIONS: NLR and tumor growth as determined by linear measurements on serial magnetic resonance imaging. MAIN OUTCOME MEASURES: VS growth, demographic factors, and NLR were compared using multi-variant logistic regression and Receiver Operating Characteristic (ROC) curve analysis. RESULTS: A total of 161 patients fulfilled the inclusion criteria, 79 with growing VS (men:women ratio = 43:36, mean age, 61.8 years) and 82 with non-growing tumors (men:women ratio = 37:45, mean age, 64.9 years). Mean NLR for the group with growing VS was 3.34 (SD [standard deviation] = 1.5) and 2.31 (SD = 0.76) for the group with non-growing VS (p = 0.001; 0.03 when adjusted for all parameters). The optimal cut-off point was NLR = 3.05 with positive predictive value 83.8% and 100% for NLR greater than 5.3. ROC analysis of the adjusted data for age, sex, and side, gave an area under the curve of 0.768, indicating NLR as a good independent predictive marker. Interestingly, the size of tumor was statistically significantly higher for the growing VS group (p = 0.001). CONCLUSION: Despite the low specificity of low NLR, our results indicate high NLR as a good predictive marker for VS growth. Confirmation by prospective studies will have a significant impact on patients' management.

Correlation of growth factor receptor expression with clinical growth in vestibular schwannomas.

OBJECTIVE: To examine the relationship between growth rate of vestibular schwannomas and the expression of various growth factor receptors. STUDY DESIGN: Retrospective case review of clinical growth rate in conjunction with a histopathologic and immunohistochemical reexamination of archival specimens. SETTING: A tertiary referral neurotologic center. PATIENTS: Three groups: a historical group to act as controls, consisting of 30 patients with sporadic vestibular schwannomas removed before the unit adopted an initial interval scan policy; a group of 14 patients with sporadic vestibular schwannomas who had undergone an initial interval scan policy, showed radiologic evidence of growth, and therefore had their schwannoma removed; and a group of 16 schwannomas removed from 11 neurofibromatosis Type 2 patients. MAIN OUTCOME MEASURES: A comparison between the three clinical groups using immunohistochemical studies to determine the level of expression of the proliferation factor Ki-67, c-erbB-2, and c-erbB-3 receptors and fibroblastic growth factor receptors 1 and 4. RESULTS: The level of expression of the proliferation factor Ki-67 was very low and similar in all three groups. C-erbB-2 and c-erbB-3 receptors were not expressed in any of the groups. fibroblastic growth factor receptor 4 expression was not significantly different, but there was a variation in the expression of fibroblastic growth factor receptor 1 between the three groups that correlated well with the differing incidence of growth in the groups. The increase in expression of fibroblastic growth factor receptor 1 in the neurofibromatosis Type 2 group was not statistically significant, but the increase in expression of fibroblastic growth factor receptor 1 in the growing sporadic group was statistically significant when compared with the historical controls. The level of fibroblastic growth factor receptor 1 expression correlates significantly with the rate of growth as measured on interval magnetic resonance imaging. CONCLUSIONS: Overexpression of fibroblastic growth factor receptor 1 has a positive correlation with the incidence and the rate of growth of sporadic vestibular schwannomas.