1/49. Bilateral facial nerve schwannomas.facial nerve schwannoma is an uncommon tumor and bilateral facial nerve tumors are extremely rare. A case is presented in which neuromas affecting the intra-canalicular and labyrinthine portions of both facial nerves occurred. Radiologic assessment demonstrated the origin of these tumors. Eventual tumor involvement of the sole functioning cochlea resulted in the development of total hearing loss. Management entailed symptomatic care and surgical resection. Auditory rehabilitation was attempted using cochlear implantation, but results have not been satisfactory. Genetic screening identified a mutation in the NF2 gene. It is proposed that this patient's condition should be considered a variant of neurofibromatosis 2 and that bilateral facial neuromas should be included in the clinical criteria for this condition.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
2/49. Severe phenotype of neurofibromatosis type 2 in a patient with a 7.4-MB constitutional deletion on chromosome 22: possible localization of a neurofibromatosis type 2 modifier gene?Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder predisposing to multiple neoplastic lesions with the hallmark of schwannoma arising at the eighth cranial nerve. NF2 shows a distinct clinical variability, with a mild and a severe form of the disease. The NF2 gene is mutated in constitutional dna of affected patients from NF2 families and in sporadic cases. Comprehensive mutation analyses in patients with severe and mild phenotypes revealed mutations in only 34%-66%. In the remaining fraction, the genetic mechanism behind the development of NF2 is unknown. Analyses of germline mutations do not provide a conclusive explanation for the observed clinical heterogeneity of NF2. It can therefore be hypothesized that other factors, e.g., modifier gene(s), contribute to the development of a more severe NF2 phenotype. We report a mentally retarded patient with the severe form of NF2 who displays a 7.4 million base pair deletion on chromosome 22. We performed a full genetic characterization of this case using heterozygozity analysis of 41 markers from chromosome 22, detailed FISH mapping of deletion breakpoints, allelotyping of all other chromosomes, and sequencing of the NF2 gene in tumor dna. Two genomically large deletions similar in size (700-800 kb), which encompass the entire NF2 gene, have been reported previously in mildly affected NF2 patients. The centromeric breakpoints of these deletions were similar to the centromeric breakpoint in the present case. However, the deletion in our patient extends over a much larger distance toward the telomere of 22q. Our results support the existence of NF2 modifier gene(s) and suggest that such a putative locus maps to a 6.5-MB interval on 22q, between D22S32 and the MB gene.- - - - - - - - - - ranking = 0.14285714285714keywords = nerve (Clic here for more details about this article) |
3/49. Auditory rehabilitation in neurofibromatosis type 2: a case for cochlear implantation.cochlear implantation has a limited but definite role in the rehabilitation of certain neurofibromatosis type 2 (NF2) patients. The presence of a dead ear either before, or after, tumour removal does not necessarily imply loss of function in the eighth nerve; in some instances the hearing loss will be cochlear. Promontory or round window electrical stimulation may help to identify those individuals with surviving eighth nerve function. In such patients multichannel cochlear implantation promises a better level of audition than the auditory brain stem implant. This paper highlights such a case and the management problems are discussed.- - - - - - - - - - ranking = 0.28571428571429keywords = nerve (Clic here for more details about this article) |
4/49. association of lower cranial nerve schwannoma with spinal ependymoma in ? NF2.A 15 year old male, who had earlier been operated for intraspinal intramedullary ependymoma, subsequently developed a right cerebello pontine (CP) angle mass. A diagnosis of right CP angle ependymoma was considered, in view of established histology of previously operated spinal lesion. Histopathological examination of the well defined extra-axial mass, which was attached with ninth cranial nerve, however revealed a schwannoma. A diagnosis of Neurofibromatosis-2 (NF2) is strongly suspected, because of well established fact, that the spinal ependymomas may have association with lower cranial nerve schwannomas in NF2. Cranial and spinal MRI screening for early diagnosis of associated, asymptomatic lesions, in suspected cases of NF2, particularly in children, is recommended.- - - - - - - - - - ranking = 0.85714285714286keywords = nerve (Clic here for more details about this article) |
5/49. The magnetless Clarion cochlear implant in a patient with neurofibromatosis 2.We present our experience using the Clarion magnetless multichannel cochlear implant with a woman profoundly deafened following bilateral acoustic neuromata as a consequence of neurofibromatosis 2 (NF2). The right neuroma had been previously removed without an attempt at neural preservation. On the left, however, a posterior fossa approach had been taken with the aim of preserving hearing. Although the left cochlear nerve appeared to be undamaged at the end of the operation, no hearing thresholds could be elicited on post-operative audiometry, because of damage either to the cochlear nerve or to the blood supply to the cochlea. Round window electrical stimulation subsequently produced a perception of sound, confirming that the cochlear nerve was capable of functioning and that a cochlear implant would be effective. Because she would need regular magnetic resonance imaging (MRI) to monitor existing and future NF2 lesions, it was decided to use a magnetless Clarion implant, which has been shown to be MRI compatible. We report our experience of using the device in this case and discuss some of the issues related to the provision of cochlear implants to patients with NF2.- - - - - - - - - - ranking = 0.42857142857143keywords = nerve (Clic here for more details about this article) |
6/49. Isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses mimicking neurofibromatosis type 2--case report.A 56-year-old male with a history of lung cancer presented with isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses (IAMs), mimicking the bilateral acoustic schwannomas of neurofibromatosis type 2, and manifesting as rapidly worsening tinnitus and bilateral hearing loss. magnetic resonance imaging showed small tumors in both IAMs with no sign of leptomeningeal metastasis. The preoperative diagnosis was neurofibromatosis type 2. Both tumors were removed and the histological diagnoses were adenocarcinoma. neuroimaging differentiation of a solitary metastatic IAM tumor from a benign tumor is difficult, although rapidly progressive eighth cranial nerve dysfunction suggests a malignant process. Metastases should be considered as a rare diagnostic possibility in a patient with small tumors in both IAMs.- - - - - - - - - - ranking = 0.14285714285714keywords = nerve (Clic here for more details about this article) |
7/49. Pseudopapilledema in neurofibromatosis type 2.PURPOSE: To report a case of neurofibromatosis type 2 with pseudopapilledema secondary to a prepapillary gliotic membrane. METHOD: Case report. Results of an ocular examination and fluorescein angiography of a patient are described. RESULTS: Fundus examination of a 14-year-old male with neurofibromatosis type 2 revealed an irregular elevation of the optic nerve and a perifoveal epiretinal membrane in the right eye. fluorescein angiography demonstrated no autofluorescence nor leakage in the area of the optic nerve. CONCLUSION: The patient has pseudopapilledema secondary to an epiretinal membrane overlying the optic disk of the right eye. The possibility of pseudopapilledema should be considered when evaluating patients with neurofibromatosis type 2 and abnormal optic nerves.- - - - - - - - - - ranking = 0.42857142857143keywords = nerve (Clic here for more details about this article) |
8/49. Intracanalicular schwannoma of the facial nerve: a manifestation of neurofibromatosis type 2.Primary facial nerve tumors, which are relatively uncommon, can present a diagnostic dilemma based on their location and variable pattern of symptoms. Of primary cranial nerve tumors, schwannomas of the facial nerve rank third in frequency after those of the eighth and fifth cranial nerves. We report an illustrative case of an intracanalicular schwannoma associated with several central nervous system tumors, consistent with neurofibromatosis type 2. Initially assumed to be an eighth cranial nerve tumor, the schwannoma was found intraoperatively to arise from the facial nerve. early diagnosis and treatment enabled excision of the tumor without sacrifice of the facial nerve. facial nerve schwannomas can resemble acoustic schwannomas in their clinical presentation. Only a heightened level of clinical vigilance will point to the correct diagnosis and result in an optimal therapeutic outcome for patients with these rare tumors.- - - - - - - - - - ranking = 1.7142857142857keywords = nerve (Clic here for more details about this article) |
9/49. radiosurgery for bilateral neurinomas associated with neurofibromatosis type 2.OBJECTIVE: The clinical course of bilateral acoustic tumors associated with neurofibromatosis (NF2) is generally troublesome, and no definite treatment strategy has been established. Follow-up results of bilateral acoustic tumors after radiosurgery are reported herein. methods: The current indications for radiosurgery are 1) a growing tumor less than 30 mm in mean diameter, 2) the ipsilateral ear has no serviceable hearing, and 3) there is risk of brain stem compression or brain stem dysfunction. Twenty cases of bilateral acoustic tumors were treated with the gamma knife, including 7 males and 13 females. The mean age was 38.2 years and the mean tumor size 24.4 mm. The tumors were treated with mean maximum and marginal doses of 26.8 Gy and 13.0 Gy, respectively. Among them, 12 patients had profound hearing loss in the ipsilateral (treated) ear, but the other 8 had serviceable hearing.RESULTS: Tumors treated with radiosurgery showed central necrosis in 60% of the cases at 6 months and in 70% at 9 months after radiosurgery. Thereafter, the tumors often demonstrated slow regression. The rate of tumor shrinkage was 20% at 12 months, 35% at 24 months, and almost 60% at 36 months. At the last follow-up (mean 33.6 months), the tumors demonstrated shrinkage in 50% and tumor control in 100%. The contralateral tumors were stable in 12 (60%) and enlarged in 8 (40%). Preservation of serviceable hearing ipsilaterally was obtained in 33.3%. Deterioration of ipsilateral facial nerve function, either in the natural course or as a complication, occurred in 10%. CONCLUSIONS: Because of good tumor control and tumor shrinkage as well as an acceptable complication rate, radiosurgery should be incorporated in the treatment strategy for bilateral acoustic tumors associated with NF2.- - - - - - - - - - ranking = 0.14285714285714keywords = nerve (Clic here for more details about this article) |
10/49. Focal amyotrophy in neurofibromatosis 2.Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterised by bilateral vestibular schwannomas and other CNS tumours including meningiomas and spinal schwannomas. Occasionally, peripheral neuropathy occurs in these patients but this is the first report of focal amyotrophy. Clinical, electrophysiological, and imaging data from four NF2 patients seen at a specialist neurofibromatosis clinic over a 4 year period are described in whom symptomatic focal amyotrophy preceded the diagnosis of NF2. Two presented with wasting and weakness of a single muscle group, several years before NF2 was diagnosed. In one patient a mononeuritis multiplex was the presenting feature of NF2, and in one patient focal wasting and weakness developed after the diagnosis of NF2 was made. In none of the four cases could a focal peripheral nerve or root neurofibroma be identified despite extensive imaging with MRI, and the limitations of neuroimaging for identifying a structural cause in patients with NF2 with a focal peripheral nerve lesion is discussed. It is likely that NF2 may affect peripheral nerve structures in a manner distinct from a compressive schwannoma.- - - - - - - - - - ranking = 0.42857142857143keywords = nerve (Clic here for more details about this article) |
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