Citations

OBJECTIVE Tumor-associated macrophages (TAMs) have been implicated as pathologic actors in phenotypically aggressive vestibular schwannoma (VS), potentially mediated via programmed death-ligand 1 (PD-L1). The authors hypothesized that PD-L1 is a key regulator of the VS immune microenvironment. METHODS Forty-six consecutive, radiation-naïve, sporadic VSs that were subtotally resected at primary surgery were assessed via immunohistochemical analysis, including analysis of CD163 and PD-L1 expression. Pathologic data were correlated with clinical endpoints, including tumor control, facial nerve function, and complications. RESULTS Baseline parameters were equivalent between stable and progressive post–subtotal resection (STR) VS. CD163 percent positivity and M2 index were significantly increased among tumors that remained stable (34% vs 21%, p = 0.02; 1.13 vs 0.99, p = 0.0008), as well as patients with favorable House-Brackmann grade I or II facial nerve function (31% vs 13%, p = 0.04; 1.11 vs 0.97, p = 0.05). PD-L1 percent positivity was significantly associated with tumor progression (1% vs 11%, p = 0.01) and unfavorable House-Brackmann grade III–VI facial nerve function (1% vs 38%, p = 0.02). On multivariate analysis, PD-L1 was independently significant in all models (likelihood ratio 4.4, p = 0.04), while CD163 was dependent in all iterations. CONCLUSIONS In contrast to prior reports, in this study, the authors observed significantly increased levels of M1, CD163 + TAMs in association with VS that progressed after STR. Progressive tumors are characterized by increased PD-L1, potentially highlighting a mechanism of immune evasion that results in TAM deactivation, tumor growth, and further infiltration of anti-tumor immune cells. Targeting PD-1/PD-L1 may offer therapeutic promise, particularly in the setting of disease control after STR.

Objective: The etiology of sensorineural hearing loss (SNHL) in patients with jugular paraganglioma (JP) whose tumors lack inner ear fistulae or vestibulocochlear nerve involvement is unknown. Recent literature has proposed that occlusion of the inferior cochlear vein may be causative. Herein, we assess the association between radiologic involvement of the cochlear aqueduct (CA) and the development of SNHL. Study Design: Blinded, retrospective review of imaging and audiometry. Setting: Tertiary center. Patients: Adults with JP. Intervention(s): None. Main Outcome Measures: Asymmetric SNHL was assessed continuously as the difference in bone conduction pure-tone average (BCPTA) between ears and as a categorical variable (≥15 dB difference at two consecutive frequencies, or a difference in speech discrimination score of ≥15%). Involvement of the CA was considered present if there was evidence of medial T2 fluid signal loss, contrast enhancement, or bony erosion/expansion. Results: Of 30 patients meeting inclusion criteria, 15 (50%) had asymmetric SNHL. CA involvement was observed in 87% of patients with asymmetric SNHL compared with 13% in those with symmetric hearing (p = 0.0001). Univariate analysis demonstrated that age, sex, and tumor volume were not associated with asymmetric SNHL. The median difference in BCPTA between ears in patients with CA involvement was 21.3 dB HL compared to 1.2 dB HL in those without CA involvement (p < 0.0001). Regression analysis demonstrates that enhancement within the CA is associated with a BCPTA difference of 19.4 dB HL (p = 0.0006). Conclusions: Cochlear aqueduct involvement by JP is associated with SNHL in the absence of inner ear fistula, vestibulocochlear nerve involvement, or brainstem compression. Correlation with operative findings or histopathologic evidence of tumor involvement may validate this intriguing imaging finding.

Objective: Previous research has shown that tumor growth during observation of small-to-medium sized sporadic vestibular schwannomas (VSs) occurs almost exclusively within 3 to 5 years following diagnosis. This has led some to consider ending surveillance after this interval. This study seeks to characterize a cohort of patients with tumors that exhibited late growth. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Adults with sporadic VSs who initially elected observation with serial magnetic resonance imaging (MRI) surveillance. Intervention(s): None. Main Outcome Measure(s): Linear tumor growth was measured in accordance with AAO-HNS reporting guidelines. Delayed growth was defined as growth ≥2 mm in linear diameter that was first detected 5 years or more from the initial MRI. Results: From a total of 361 patients, 172 experienced tumor growth during the interval of observation. Fourteen of these 172 patients (8.1%) experienced late growth occurring at 5 years or beyond. Among patients with delayed growth, the fastest growth rate after extended quiescence was 1.33 mm/yr, and the longest delay before tumor growth detection was 11.1 years. Additional treatment was recommended for six (42.9%) of the patients with delayed growth. Of 68 tumors that remained in the IAC, 11 (16.2%) demonstrated delayed growth. Of 66 tumors that presented in the CPA, 2 (3.0%) demonstrated delayed growth. Initial size was larger for tumors demonstrating early growth compared with those with delayed growth. For tumors within the IAC, those with early growth had a significantly higher median growth rate than those with delayed growth (1.40 vs. 0.45 mm/yr, p < 0.001). Conclusions: Delayed growth encompassed 8.1% of growing VSs and 3.9% of all observed tumors. Patients with delayed growth exhibited slower growth rates compared with those who were diagnosed with growth early in their observation course. These findings support the need for lifelong surveillance of untreated VSs given the possibility of clinically significant delayed growth. Increasing the time interval between MRI studies after 5 years is a reasonable concession to balance practicalities of cost and convenience with risk of delayed of tumor growth.

OBJECTIVERadiation dose to the cochlea has been proposed as a key prognostic factor in hearing preservation following stereotactic radiosurgery (SRS) for vestibular schwannoma (VS). However, understanding of the predictive value of cochlear dose on hearing outcomes following SRS for patients with non-VS tumors of the lateral skull base (LSB) is incomplete. The authors investigated rates of hearing loss following high-dose SRS in patients with LSB non-VS lesions compared with patients with VS.METHODSPatients with LSB meningioma or jugular paraganglioma and serviceable pretreatment hearing who underwent SRS treatment during 2007–2016 and received a modiolus dose > 5 Gy were included in a retrospective cohort study, along with a similarly identified control group of consecutive patients with sporadic VS.RESULTSSixteen patients with non-VS tumors and a control group of 43 patients with VS met study criteria. Serviceable hearing, defined as American Academy of Otololaryngology–Head and Neck Surgery class A/B, was maintained in 13 non-VS versus 23 VS patients (81% vs 56%, p = 0.07). All 3 instances of hearing loss in non-VS patients were observed in cerebellopontine angle (CPA) meningiomas. Non-VS with preserved hearing had a median modiolus dose of 6.9 Gy (range 5.7–19.2 Gy), versus 7.4 Gy (range 5.4–7.6 Gy) in those patients with post-SRS hearing loss (p = 0.53). Sporadic VS patients received an overall median modiolus point-dose of 6.8 Gy (range 5.4–11.7 Gy).CONCLUSIONSThe modiolus dose threshold of 5 Gy does not predict hearing loss in patients with non-VS tumors undergoing SRS, suggesting that dosimetric parameters derived from VS may not be applicable to this population. Differential rates of hearing loss appear to vary by pathology, with paragangliomas and petroclival meningiomas demonstrating decreased risk of hearing loss compared to CPA meningiomas that may directly compress the cochlear nerve similarly to VS.

Objective: The treatment paradigm for jugular paraganglioma (JP) has changed considerably over time with the wider adoption of stereotactic radiosurgery (SRS). To the best of the authors’ knowledge, there are no published studies that use validated patient-reported outcome measures to ascertain quality of life (QoL) outcomes following SRS for JP when used in single or combined modality treatment regimens. Study Design: Cross-sectional survey. Setting: Tertiary referral center. Patients: Adult patients with JP treated with primary SRS or SRS following primary surgery between 1990 and 2017. Interventions(S): Surgery and/or Gamma Knife SRS. Main Outcome Measures: Global and treatment-related QoL and differences in QoL based on treatment approach. Results: Sixty-nine surveys were distributed and a total of 26 completed surveys were received (38% response rate). Among respondents, the median age at SRS was 53 years and 16 of the 26 patients (62%) were female. Median follow-up was 97 months. Nineteen patients (73%) were treated with primary SRS or staged SRS following intentional subtotal resection (STR; hereafter referred to as “staged SRS”), while the remainder (n = 7, 27%) were treated with SRS for recurrent JP. Median physical and mental health QoL PROMIS-10 T-scores regardless of treatment strategy were 39.8 and 38.8, respectively, while median SF36 physical and mental component subscores were similar to national averages and non-tumor controls. When comparing general physical and mental health QoL scores, there was no significant difference between patients treated with primary or staged SRS and those treated with SRS for recurrent JP. However, age-adjusted swallowing function among patients treated with primary or staged SRS was better than in those patients treated with SRS for recurrent JP (p = 0.05). Conclusions: Patients treated with primary or staged SRS for JP tend to exhibit better swallowing outcomes than those treated with SRS for recurrent JP. However, the majority of overall and disease-specific quality of life measures were not different between groups. Based on the low incidence of new cranial neuropathy following SRS, it is likely that initial surgical morbidity is the primary contributor to this outcome. Disease-specific overall quality of life measures, akin to those already used for other benign skull base tumors, are necessary to better gauge physical and mental health outcomes following treatment for JP. Though limited by small sample size, this represents the first study to gauge QoL outcomes following treatment for JP.

Objective: To remove barriers and improve access for patients seeking cochlear implantation. Study Design: Prospective quality improvement study at a large tertiary academic care center. Methods: A Kaizen quality improvement model was applied over the course of a year. Four weeklong meetings were used to identify areas for improvement and remediation. Data were collected at baseline, 90-days, and 1-year postcompletion of the project. Outcome measures included lead times, defined as the wait time between first contact with the clinic and the first appointment, and the wait time between surgery and activation, and cycle times defined as the total test time needed to determine cochlear implant candidacy, and total time needed to complete initial activation. The total inventory kept as clinic stock was also calculated Results: Kaizen team members collected data for each outcome measure. After the Kaizen principles were applied, the following outcomes were observed: median lead times between first contact with the clinic to candidacy testing, candidacy testing to surgery, and surgery to activation of the implant remained stable from baseline to 1-year follow-up. Median cycle time for candidacy testing decreased from 7.3 hours at baseline to 3.0 hours at 1-year follow-up. Cycle times for initial activation of the device did not change over time. The total inventory of clinic stock was reduced by 31%. Conclusions: Though outcomes for lead and cycle times varied, implementation of Kaizen principles was found to be an effective method for completing this quality improvement project at a large cochlear implant program overall. Level of Evidence: 3a

ObjectiveThe purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve “hemangiomas” to confirm that these lesions are most characteristic of venous malformations rather than neoplasms.Study DesignRetrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed.Materials and MethodsA panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1).ResultsLesions were composed of dilated vascular spaces with a simple, CD31‐positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common.ConclusionsOn the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations.Level of Evidence4

Objectives To present a rare case of traumatic facial neuroma involving the geniculate ganglion and review relevant literature. Patient Thirty-year-old man. Intervention Microsurgical resection via combined mastoid-middle fossa approach with great auricular nerve interpositional graft. Main Outcome Measures Patient demographics and pre- and postoperative facial nerve function. Results A 30-year-old man with a reported history of prior Bell's palsy developed progressive complete (House–Brackmann VI) right facial paralysis following blunt trauma. Imaging was strongly suggestive of a geniculate ganglion hemangioma. As the patient had no spontaneous improvement in his poor facial function over the course of 9 months, he underwent resection of the facial nerve lesion with great auricular nerve graft interposition via a combined mastoid-middle fossa approach. Histopathology demonstrated disorganized fascicles, with axonal clustering reminiscent of sprouting/regeneration following trauma. No cellular proliferation or vascular malformation was present. Conclusion Traumatic facial nerve neuromas can occur following temporal bone trauma and can closely mimic primary facial nerve tumors. Akin to the management of geniculate ganglion hemangioma and schwannoma, preoperative facial function largely dictates if and when surgery should be pursued.