Clinical and radiological features of intracranial ancient schwannomas: a single-institution, retrospective analysis.

Ancient schwannoma (AS) is a subtype of schwannoma characterized by slow progression despite degenerative changes in pathology. Although it is considered a benign tumor, most previous reports have focused on extracranial AS; therefore, the clinical characteristics of intracranial AS is not clear. We included 174 patients who underwent surgery for sporadic intracranial schwannoma, and 13 patients (7.5%) were diagnosed with AS. Cysts were significantly more common in patients with AS than conventional schwannomas (92.3% vs. 44.7%, p < 0.001), as was bleeding (38.5% vs. 6.9%, p = 0.003) and calcification (15.4% vs. 1.3%, p = 0.029). The maximum tumor diameter was also larger in patients with AS (35 mm vs. 29 mm, p = 0.017). The median duration from symptom onset to surgery (7.0 vs. 12.5 months, p = 0.740) did not significantly differ between groups, nor did the probability of postoperative recurrence (p = 0.949). Intracranial AS was strongly associated with cyst formation and exhibited a benign clinical course with a lower rate of recurrence and need for salvage treatment. Extracranial AS is reportedly characterized by a slow progression through a long-term clinical course, whereas intracranial AS did not progress slowly in our study and exhibited different clinical features to those reported for extracranial AS.

The Validity of the Koos Classification System With Respect to Facial Nerve Function.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. Our prior study demonstrated excellent reliability. No study has yet assessed its validity. OBJECTIVE: To present a retrospective study designed to assess the validity of the Koos grading system with respect to facial nerve function following treatment of 81 acoustic schwannomas. METHODS: We collected data retrospectively from 81 patients with acoustic schwannomas of various Koos grades who were treated with microsurgical resection or stereotactic radiosurgery. House-Brackmann (HB) scores were used to assess facial nerve function and obtained at various time points following treatment. We generated Spearman's rho and Kendall's tau correlation coefficients along with a logistic regression curve. RESULTS: We found no significant difference in the presence or absence of facial dysfunction by Koos classification when looking at all patients. There was a positive but fairly weak correlation between HB score and Koos classification, which was only significant at the first postoperative clinic appointment. There was a statistically significant difference in the presence or absence of facial dysfunction between patients treated with surgery vs radiation, which we expected. We found no statistically significant difference when comparing surgical approaches. Logistic regression modeling demonstrated a poor ability of the Koos grading system to predict facial nerve dysfunction following treatment. CONCLUSION: The Koos grading system did not predict the presence of absence of facial nerve dysfunction in our study population. There were trends within subgroups that require further exploration.

Gene expression profiles between cystic and solid vestibular schwannoma indicate susceptible molecules and pathways in the cystic formation of vestibular schwannoma.

Previous research has shown that although NF2 gene mutation is the major cause of vestibular schwannoma (VS), it may not directly participate in cystic VS (CVS). To elucidate the underlying potential genetic mechanisms in the cystic formation of VS, we compared differences in gene expression between solid VS (SVS) and CVS via a bioinformatics analysis. The cDNA microarray method and miRNA sequencing were performed on 29 representative VSs (17 CVSs and 12 SVSs). A differential expression analysis was used to identify differentially expressed mRNAs (DEmRNAs) and miRNAs (DEmiRNAs). Then, miRNA-mRNA regulatory networks were constructed. Gene ontology (GO), a KEGG pathway enrichment analysis, and the protein-protein interaction (PPI) were used to analyze the co-differentially expressed DEmRNAs at the functional level. From the differential expression analyses, 1304 DEmRNAs, 55 DEmiRNAs, and hub genes including PTEN, FOXO1, FOXO3, VEGFA, and SIRT1 were identified. Histological evidence is presented to confirm the makeup of the hubs, which corresponded with the cDNA microarray. Our analysis revealed that the maps of apoptosis, cellular response to hypoxia, and the PI3K-Akt, AMPK, FOXO, and chemokine signaling pathways were significantly enriched. In addition, the TUNEL assay, immunoblotting analysis, and transmission electron microscope revealed increased degenerative changes in CVS. These findings could be the foundation for understanding the potential role of differential genes in the cystic formation of VS and be helpful in exploring the potential biomarkers for the differential diagnosis, prognosis, and development of drug targets for CVS.

Koos Classification of Vestibular Schwannomas: A Reliability Study.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. While this classification system is widely reported in the literature, to date no study has assessed its reliability. OBJECTIVE: To assess the intra- and inter-rater reliability of the Koos classification system. METHODS: After institutional review board approval was obtained, a cross-sectional group of the Magnetic Resonance imagings of 40 patients with vestibular schwannomas varying in size comprised the study sample. Four raters were selected to assign a Koos grade to 50 total scans. Inter- and intrarater reliability were calculated and reported using Fleiss' kappa, Kendall's W, and Intraclass correlation coefficient (ICC). RESULTS: Inter-rater reliability was found to be substantial when measured using Fleiss' kappa (.71), extremely strong using Kendall's W (.92), and excellent as calculated by ICC (.88).Intrarater reliability was perfect for 3 out of 4 raters as assessed using weighted kappa, Kendall's W and ICC, with the intrarater agreement for the fourth rater measured as extremely high. CONCLUSION: We have demonstrated that the Koos classification system for vestibular schwannoma is a reliable method for tumor classification. This study lends further support to the results of current literature using Koos grading system. Further studies are required to evaluate its validity and utility in counseling patients with regard to outcomes.

[Surgical treatment of acoustic neuromas (vestibular schwannomas)]. / Khirurgicheskoe lechenie nevrinom slukhovogo nerva (vestibuliarnykh shvannom).

Clinical guidelines are topical systematically developed provisions designed to help the doctor make a decision about a treatment approach in certain clinical situations; they provide information on conducting diagnostic and screening tests, the amount of medical and surgical care, and other aspects of clinical practice. Vestibular schwannomas account for 8% of all intracranial lesions, up to 30% of posterior cranial fossa tumors, and 85% of cerebellopontine angle tumors. The incidence rate of acoustic neuromas is approximately 1 case per 100000 population per year. The paper addresses the issues of classification, diagnosis, and treatment of acoustic neuromas. The guidelines discuss in detail the key aspects of formulation of clinical diagnosis, classification features, definition of the indications for surgical or radiation treatment, and principles of expectant treatment in vestibular schwannomas. The article pays particular attention to surgical treatment of acoustic neuromas and describes the criteria for choosing a surgical approach, use of modern surgical equipment, and stages of tumor resection. On the basis of the accepted clinical classification, we propose the algorithms of action depending on the disease stage, pathological process dynamics, patient's age, and clinical manifestations. The key points of the clinical guidelines rely on evidence-based criteria. The work is intended for neurosurgery practitioners.

Simultaneously occurring tumours within the same cerebello-pontine angle: refining literature definitions and proposal for classification.

We report on an unusual case of a patient, not affected by neurofibromatosis, harbouring two radiologically spatially contiguous tumours within the same cerebello-pontine angle. Pathological findings were consistent with the diagnosis of two spatially distinct primary tumours, namely a meningioma and a schwannoma. We proposed a classification of tumours occurring at the same location consistent with the different spatial arrangement and histological nature of these conditions. The correct classification of these nosological entities will allow further more accurate evaluations of these cases in order to clarify the pathogenesis, prognosis and best treatment of each one.

Classification of otoneurological cases according to Bayesian probabilistic models.

We show that Bayesian methods can be efficiently applied to the classification of otoneurological diseases and to assess attribute dependencies. A set of 38 otoneurological attributes was employed in order to use a naive Bayesian probabilistic model and Bayesian networks with different scoring functions for the classification of cases from six otoneurological diseases. Tests were executed on the basis of tenfold crossvalidation. We obtained average sensitivities of 90%, positive predictive values of 92% and accuracies as high as 97%, which is better than our earlier tests with neural networks. Our assessments indicated that Bayesian methods have good power and potential to classify otoneurological patient cases correctly even if this is often a complicated task for the best specialists. Bayesian methods classified the current medical data and knowledge well.

Cystic vestibular schwannoma: classification, management, and facial nerve outcomes.

OBJECTIVE: Review of postoperative morbidity and facial nerve outcomes of cystic vestibular schwannoma (CVS) patients compared with solid vestibular schwannoma (SVS) patients and a proposal for a new CVS classification system. STUDY DESIGN: Retrospective review. SETTING: Tertiary care facility. PATIENTS: Ninety-six patients with surgically treated CVS (1998-2008). Outcomes were assessed in a subpopulation of 57 patients with greater than or equal to 1-year follow-up compared with 57 SVS patients. INTERVENTION: Fifty-six CVS patients underwent the enlarged translabyrinthine approach with transapical extension (Type I), and 1 patient underwent a transcochlear/transzygomatic approach. MAIN OUTCOME MEASURE: Preoperative and postoperative (at least 1 yr) House-Brackmann facial nerve (HBFN) grade evaluation. RESULTS: Favorable HBFN grades (I-III) were observed in 46 (81%) CVS patients, and unfavorable HBFN grades (IV-VI) were seen in 11 (19%) CVS patients. Comparison of tumor size and 1-year HBFN grades showed significant, moderate to strong, Pearson correlation (0.38). Comparison of long-term facial nerve outcomes with a sample of 57 matched SVS patients showed no significant difference (p = 0.74). When the tumor was adherent to the facial nerve and a dissection plane could not be developed between the cyst wall and the nerve, only subtotal resection could offer the CVS patients a normal facial nerve outcome. CONCLUSION: In most CVS cases, complete resection should be foreseen. Central and thick-walled tumors can be removed in almost all cases. However, when peripheral thin-walled, adherent, cystic tumors are confronted and the cysts are medially or anteriorly located, we recommend subtotal resection, leaving portions of the cyst walls on neurovascular structures and on the facial nerve. This surgical strategy allows us to improve facial nerve outcomes and to reduce complications.

Hearing preservation in surgery for large vestibular schwannomas.

OBJECT: Hearing preservation remains a challenging problem in vestibular schwannoma (VS) surgery. The ability to preserve hearing in patients with large tumors is subject to particular difficulty. In this study, the authors focus on hearing preservation in patients harboring large VSs. METHODS: A total of 344 consecutive patients underwent surgical removal of VSs over the past 9 years. Of these 344 cases, 195 VSs were > 20 mm in maximum cisternal diameter. Of the 195 cases, hearing preservation surgery was attempted for 54 patients who had a Class A, B, C, or D preoperative hearing level; that is, a pure tone average or= 50% according to the Sanna/Fukushima classification. The tumors were classified as moderately large (21-30 mm based on the largest extrameatal diameter), large (31-40 mm), and giant (>or= 41 mm) according to the international criteria. The authors categorized patients with Class A, B, C, D, or E hearing (pure tone average or= 40%) as having preserved hearing postoperatively. RESULTS: Forty-one tumors (75.9%) were totally removed and 13 (24.1%) had near-total removal. Of the 54 patients, 29 maintained their hearing postoperatively; the overall hearing preservation rate was 53.7%. Analysis based on the preoperative hearing level showed that hearing was preserved in 14 (77.8%) of 18 cases for Class A; in 8 (47.1%) of 17 cases for Class B; in 4 (57.1%) of 7 cases for Class C; and in 3 (25.0%) of 12 cases for Class D. In addition, according to the analysis based on the tumor size, 20 (52.6%) of 38 patients with moderately large tumors retained their hearing, as did 5 (50.0%) of 10 patients with large tumors and 4 (66.7%) of 6 patients with giant tumors. Complications included 2 cases of bacterial meningitis that were cured by intravenous injection of antibiotics, 3 cases of subcutaneous CSF leakage that resolved without any surgical repair, and 1 case of temporary abducent nerve palsy. There were no deaths in this series. CONCLUSIONS: The results indicate that successful hearing preservation surgery in large VSs is possible with meticulous technique and attention to adhesions between the tumor and the cochlear nerves.

On machine learning classification of otoneurological data.

A dataset including cases of six otoneurological diseases was analysed using machine learning methods to investigate the classification problem of these diseases and to compare the effectiveness of different methods for this data. Linear discriminant analysis was the best method and next multilayer perceptron neural networks provided that the data was input into a network in the form of principal components. Nearest neighbour searching, k-means clustering and Kohonen neural networks achieved almost as good results as the former, but decision trees slightly worse. Thus, these methods fared well, but Naïve Bayes rule could not be used since some data matrices were singular. Otoneurological cases subject to the six diseases given can be reliably distinguished.

Caracterización clínica del schwannoma del VIII par. ¿Son suficientemente expresivos sus síntomas? / Clinical picture of 8th pair schwannoma. Is it expressive enough?

Objetivo: Determinar la semiología característica del schwannoma del VIII par craneal en función de su estadio por imagen. Material y método: Estudio descriptivo a partir de 71 sujetos diagnosticados en nuestra consulta o remitidos a nuestro centro para tratamiento entre 1997 y 2003. Se recoge el sexo y la edad, así como los síntomas que presentaba el paciente, diferenciando el síntoma de inicio. Determinación del estadio del tumor según criterios de imagen de la clasificación de Tos y Thomsen. Resultados: La media de edad es de 64,6 (intervalo, 20-87) años. Llama la atención que el tramo de edad entre los 52 y 70 años acumula el 62 % de los casos. La incidencia es levemente mayor en mujeres y en el oído izquierdo. Los síntomas predominantes son los derivados de la afección del VIII y el VII pares craneales, asociándose síntomas por afección de otros pares craneales y del ángulo pontocerebeloso en tumores mayores, aunque existe una enorme variabilidad tanto entre casos del mismo estadio como en la clínica de inicio (first sympthom). Destacamos en nuestro estudio la variabilidad de la preservación de la audición entre los diferentes pacientes y el alto número de casos afectos de clínica vestibular o facial, tanto motriz como sensitiva. Asimismo, hay formas de inicio sorprendentes por su infrecuencia. Conclusiones: No existe patrón clínico típico de comienzo del schwannoma del VIII par. Cualquier síntoma audiovestibular o facial, por sutil que fuere, puede ser la primera expresión clínica de un schwannoma del VIII par. Ningún síntoma es patrimonio de ningún estadio, con la excepción de los propios de la afección de la fosa posterior

Objective: To describe the stage-related clinical features of 8th cranial nerve schwannoma. Material and method: Descriptive study of 71 patients whose diagnosis and/or treatment have been carried out at our centre between 1997-2003. Gender, age, and symptoms were considered, with special attention to gender. Determination of tumoral stage following Tos and Thomsen image criteria. Results: The mean age was 64.6 (range, 20-87) with a marked incidence between 52 and 70 years (62 % of the whole), slightly higher in females and in the left ear. The main symptoms were those derived from involvement of the 7th and 8th cranial nerves, with other cranial nerves and cerebello-pontine structures being involved in larger tumours, although a high variability was noted in clinical patterns of same-stage cases and in the first symptom. Our study also found a high variability in hearing conservation and a marked frequency of vestibular or facial (motor and sensory) symptoms. There were also very infrequent forms of presentation that are highlighted. Conclusions: There is no typical clinical pattern and no typical first symptom in 8th cranial nerve schwannomas. Any audiovestibular or facial symptom, even the slightest, may be the first expression of 8th cranial nerve schwannoma. There is no stage-specific symptom except for those with involvement of the cerebello-pontine or cerebral structures

Stereotactic radiosurgery for vestibular schwannomas: analysis of 317 patients followed more than 5 years.

OBJECTIVE: Many investigators have reported successful treatment of vestibular schwannomas with gamma knife radiosurgery (GKRS). However, long-term outcomes should be evaluated before concluding that GKRS is truly safe and effective for the treatment of vestibular schwannomas. METHODS: Between May 1991 and December 1998, 346 consecutive patients (excluding those presenting with neurofibromatosis Type 2) were treated with GKRS. Of these, 317 patients were assessed. Twenty-nine patients were lost to follow-up within 5 years. RESULTS: The median follow-up period was 7.8 years. Of 301 patients who underwent serial follow-up imaging, two (1%) experienced complete remission, 184 (61%) experienced partial remission, 93 (31%) had stable tumors, and 22 (7%) experienced treatment failure. The actuarial 5- or 10-year progression-free survival (PFS) rate was 93 and 92%, respectively. Tumors less than 15 cm3 in volume (10-yr PFS, 96%; P < 0.001) or which did not compress the brainstem and deviate the fourth ventricle (10-yr PFS, 97%; P = 0.008) resulted in significantly better PFS rates. Failure of treatment usually occurred within 3 years. When the tumor was treated with a marginal dose of 13 Gy or less, the hearing preservation rate was 68%, transient facial palsy developed at a rate of 1%, and facial numbness developed at a rate of 2%. CONCLUSION: GKRS proved to be a safe and effective treatment for patients followed longer than 5 years who presented with tumors with a volume of less than 15 cm3 and who did not have significant fourth ventricle deviation. Good functional outcomes were observed in this group of patients.

Headache: a quality of life analysis in a cohort of 1,657 patients undergoing acoustic neuroma surgery, results from the acoustic neuroma association.

OBJECTIVES: On the basis of survey results of the Acoustic Neuroma Association (ANA), we report patient ratings of postoperative headache (POH) symptoms, determine its effect on quality of life (QOL), and review the literature regarding POH after acoustic neuroma (AN) treatment. STUDY DESIGN: In this cohort study, 1,657 patients who underwent surgical treatment of AN reported their experiences of POH. METHODS: A detailed questionnaire was mailed to members of the ANA to identify preoperative and postoperative headache symptoms, complications, and long-term effects on physical and psychosocial function. Questions were answered by 1657 (85.4%) respondents that were intended to qualify and quantify the effects of POH, including QOL issues. Responses were analyzed by tumor size, surgical approach, and patient age and sex. Statistical analysis was performed with the SPSS software. RESULTS: Preoperative headache was reported in approximately one third of respondents. Typical POHs occurred more than once daily (46%), lasted 1 to 4 hours in duration (43.1%), and were of moderate intensity (62.6%). The worst headaches were rated as "severe" by 77% of respondents. Treatment most often reported for typical headaches were nonprescription medications including nonsteroidal anti-inflammatory drugs in 61.3% (P < .01) and regular use of narcotics in 15%. Patients who underwent the retrosigmoid approach were significantly more likely to report their worst POH as "severe" (82.3%) compared with the translabyrinthine (75.2%) and middle fossa approaches (63.3%). Women and younger patients tended to have poorer outcomes with regard to POHs. CONCLUSIONS: In this large cohort study of AN patients, POH was a significant morbidity among AN patients with persistent headaches. Treating physicians should be aware of the risk factors identified and the effect POH has on the QOL when counseling patients regarding optimal treatment management.

[Small acoustic neuroma: observation or treatment? A review of 207 cases]. / Les neurinomes de l'acoustique de petite taille: surveillance ou traitement? A propos de 207 cas.

The management of small acoustic neuromas (AN) whether localized in an intracanalar position (stage I) or with a small extension of less then 2 cm into the cerebellopontine angle (stage II) remains under debate. Proposed strategies include surgery, stereotactic irradiation and observation. From 1987 to 1997, among 343 AN referred to our department, 207 were small (83 stage I and 124 stage II). Initially, 72 patients were treated conservatively mainly because of their age (over 60-65) and 132 were operated on. Three patients underwent irradiation because of their poor general condition. Significant tumor growth was observed in 15 cases in the conservative treatment group; 14 of these patients underwent secondary surgery and one irradiation. Among the 146 AN operated on (132 initially and 14 secondarily), 142 small AN were operated on via a transpetrosal approach (64% translabyrinthine, 21% middle-fossa and 15% retrosigmoid) and 4 AN, which became large tumors during the observation period, were treated through the translabyrinthine approach. No mortality was observed in our series. Postoperative complications included 11 CSF leakages necessitating reoperation (8%). In 93% of the cases, postoperative facial function at one year was good. Hearing preservation was attempted in 51 selected cases (pure tone average=50 dB, speech discrimination score 100%) with a 51% success rate (53% and 48% through middle-fossa and retrosigmoid approaches respectively). In our opinion, surgery with this risk-benefit ratio is indicated for small AN, except in the elderly for whom conservative management is preferred and in patients in poor clinical condition with a growing AN, for whom irradiation is recommended.

[Fractionated radiation therapy long-term effectiveness in the treatment of cerebello-pontine angle schwannomas: 12 years of experience in 30 cases]. / Efficacité à long terme de la radiothérapie fractionnée dans le traitement des schwannomes de l'angle ponto-cérébelleux : expérience de 12 ans sur 30 cas.

UNLABELLED: The purpose of this research was to evaluate long-term results of fractionated radiation therapy (RT) in the treatment of cerebello-pontine angle schwannomas. METHODS: from January 1986 to October 1995, 29 patients with stage III and IV scwhannomas were treated with external fractionated RT. One patient was irradiated on both sides and indication for RT was as follows: a) poor general condition or old age contraindicating surgery, 16 cases; b) hearing preservation in bilateral tumors after contralateral tumor removal, 6 cases; c) partial resection or high risk of recurrence after subsequent surgery for relapse, 5 cases; d) non surgical relapse, 3 cases. Most patients were irradiated with 6 to 10 MV photons. A three- to four-field technique with coplanar static beams and conformal blocks was used. Doses were calculated on a 95 % isodose and were given 5 days a week for a mean total dose of 51 Gy (1.8 Gy/fraction). RESULTS: Median follow-up from RT was 66 months (7 to 120); seven patients died, two with progressive disease, five from non tumoral cause. Two patients underwent total removal after RT (1 stable and 1 growing tumor). On the whole, tumor shrinkage was observed in 13 patients (43.3 %), stable disease in 14 (46.6 %), and tumor progression in three. Hearing was preserved in 4 out of 6 hearing patients (1 class A hearing, 2 class B and 1 class C). No patient experienced CN5 or CN7 neuropathy. CONCLUSION: long-term efficacy or fractionated RT is well documented in this series. Acute and delayed tolerance was excellent. Hearing can be preserved for a long time.

A comprehensive classification system of vestibular schwannomas.

Because traditional classifications of vestibular schwannomas (according to relative size) cannot comprehensively describe lesions that grow in different patterns after arising in regions as diverse as the cerebellopontine (CP) angle, the internal auditory canal, and the region lateral to the fundus of the internal auditory canal (labyrinth), we developed a new system to classify vestibular schwannomas, a system that describes the anatomical structures involved by the tumour, rather than size alone. The vestibular schwannoma is classified first by location and then by extent. Our system provides surgeons information helpful in choosing the surgical approach, in estimating the difficulty of tumour excision, and in determining whether hearing might be preserved. Our system also avoids confusion and misunderstanding in discussions of treatment results because it reflects the diverse biological characteristics of vestibular schwannomas.