A challenging case of sporadic melanocytoma of the jugular foramen.

BACKGROUND: The jugular foramen (JF) can be the site of several tumours. Paragangliomas, schwannomas and meningiomas are the most commonly reported. We describe a case of melanocytoma originating from the JF and presenting with an accessory nerve palsy. ILLUSTRATIVE CASE: A 48-year-old woman presented with a 6-month history of cervical and left shoulder pain with wasting and weakness of the left trapezius. A Magnetic Resonance Imaging (MRI) showed a T1-hyperintense, T2-isointense, heterogeneously enhancing lesion involving the left JF and extending into the cerebello-medullary and cerebello-pontine cisterns. A retrosigmoid craniotomy was performed and a near-total removal achieved. The accessory nerve was involved by tumour and could not be preserved. Given the diagnostic uncertainty between melanotic schwannoma, metastatic melanoma and meningeal melanocytoma, next generation sequencing and genome-wide DNA methylation arrays were performed, documenting a mutation in GNA11 (c.6226A>T, p. Gln209Leu) and a methylation profile consistent with melanocytoma. The patient underwent adjuvant fractionated radiotherapy of the tumour remnant. A follow-up MRI 4 years after surgery did not show any tumour recurrence. CONCLUSIONS: The differential diagnosis of skull base pigmented tumours can be challenging, particularly when they occur in unusual locations such as the JF. They can be misdiagnosed given their similar clinical, neuroradiological and pathological features if anatomy of the site of origin is not carefully considered and molecular tests are not performed, leading to erroneous treatment and follow-up planning.

Spinal ependymomas in NF2: a surgical disease?

The management of spinal cord ependymomas in Neurofibromatosis Type 2 (NF2) has traditionally been conservative, in contrast to the management of sporadic cases; the assumption being that, in the context of NF2, they did not cause morbidity. With modern management and improved outcome of other NF2 tumours, this assumption, and therefore the lack of role for surgery, has been questioned. To compare the outcome of conservative treatment of spinal ependymomas in NF2 with surgical intervention in selected patients. Retrospective review at two NF2 centers, Manchester, UK and Paris/Lille, France. In Manchester patients were managed conservatively. In France surgery was a treatment option. Inclusion in the study was based on tumor length of greater than 1.5 cm. The primary parameter assessed was acquired neurological deficit measured by the Modified McCormick Outcome Score. 24 patients from Manchester and 46 patients from France were analyzed. From Manchester, 27% of these patients deteriorated during the course of follow-up. This effectively represents the natural history of ependymomas in NF2. Of the surgical cases, 23% deteriorated postoperatively, but only 2/18 (11%) of those operated on in the NF2 specialist centers. Comparison of the two specialist centers Manchester/France showed a significantly improved outcome (P = 0.012, χ2 test) in the actively surgical center. Spinal ependymomas produce morbidity. Surgery can prevent or improve this in selected cases but can itself can produce morbidity. Surgery should be considered in growing/symptomatic ependymomas, particularly in the absence of overwhelming tumor load where bevacizumab is the preferred option.

Hearing optimisation in neurofibromatosis type 2: A systematic review.

BACKGROUND: It is common for patients with neurofibromatosis type 2 to develop bilateral profound hearing loss hearing loss, and this is one of the main determinants of quality of life in this patient group. OBJECTIVES: The aim of this systematic review was to review the current literature regarding hearing outcomes of treatments for vestibular schwannomas in neurofibromatosis type 2 including conservative and medical management, radiotherapy, hearing preservation surgery and auditory implantation in order to determine the most effective way of preserving or rehabilitating hearing. SEARCH STRATEGY: A MESH search in PubMed using search terms (('Neurofibromatosis 2' [Mesh]) AND 'Neuroma, Acoustic'[Mesh]) AND 'Hearing Loss' [Mesh] was performed. A search using keywords was also performed. Studies with adequate hearing outcome data were included. With the exception of the cochlear implant studies (cohort size was very small), case studies were excluded. EVALUATION METHOD: The GRADE system was used to assess quality of publication. Formal statistical analysis of data was not performed because of very heterogenous data reporting. RESULTS: Conservative management offers the best chance of hearing preservation in stable tumours. The use of bevacizumab probably improves the likelihood of hearing preservation in growing tumours in the short term and is probably more effective than hearing preservation surgery and radiotherapy in preserving hearing. Of the hearing preservation interventions, hearing preservation surgery probably offers better hearing preservation rates than radiotherapy for small tumours but recurrence rates for hearing preservation surgery were high. For patients with profound hearing loss, cochlear implantation provides significantly better auditory outcomes than auditory brainstem implantation. Patients with untreated stable tumours are likely to achieve the best outcomes from cochlear implantation. Those who have had their tumours treated with surgery or radiotherapy do not gain as much benefit from cochlear implantation than those with untreated tumours. CONCLUSIONS: This review summarises the current literature related to hearing preservation/rehabilitation in patients with NF2. Whilst it provides indicative data, the quality of the data was low and should be interpreted with care. It is also important to consider that the management of vestibular schwannomas in NF2 is complex and decision-making is determined by many factors, not just the need to preserve hearing.

Geniculate neuralgia: a systematic review.

OBJECTIVE: To systematically summarise the peer-reviewed literature relating to the aetiology, clinical presentation, investigation and treatment of geniculate neuralgia. DATA SOURCES: Articles published in English between 1932 and 2012, identified using Medline, Embase and Cochrane databases. METHODS: The search terms 'geniculate neuralgia', 'nervus intermedius neuralgia', 'facial pain', 'otalgia' and 'neuralgia' were used to identify relevant papers. RESULTS: Fewer than 150 reported cases were published in English between 1932 and 2012. The aetiology of the condition remains unknown, and clinical presentation varies. Non-neuralgic causes of otalgia should always be excluded by a thorough clinical examination, audiological assessment and radiological investigations before making a diagnosis of geniculate neuralgia. Conservative medical treatment is always the first-line therapy. Surgical treatment should be offered if medical treatment fails. The two commonest surgical options are transection of the nervus intermedius, and microvascular decompression of the nerve at the nerve root entry zone of the brainstem. However, extracranial intratemporal division of the cutaneous branches of the facial nerve may offer a safer and similarly effective treatment. CONCLUSION: The response to medical treatment for this condition varies between individuals. The long-term outcomes of surgery remain unknown because of limited data.

The management of cochlear nerve deficiency.

The assessment process is critical in deciding whether a profoundly deaf child with cochlear nerve deficiency (CND) will be suitable for a cochlear or auditory brainstem implant (ABI). Magnetic resonance imaging (MRI) using submillimetric T2 weighted gradient echo or turbo spin echo sequences is mandatory for all profoundly deaf children to diagnose CND. Evidence of audition on behavioural or electrophysiological tests following both auditory and electrical stimulation sometimes allows identification of significant auditory tissue not visible on MRI. In particular electric auditory brainstem response (EABR) testing may allow some quantification of auditory tissue and help decide whether a cochlear implant will be beneficial. Age and cognitive development are the most critical factors in determining ABI benefit. Hearing outcomes from both cochlear implants and ABIs are variable and likely to be limited in children with CND. A proportion of children will get no benefit. Usually the implants would be expected to provide recognition of environmental sounds and understanding of simple phonetics. Most children will not develop normal speech and they will often need to learn to communicate with sign language. The ABI involves a major neurosurgical procedure and at present the long term outcomes are unknown. It is therefore essential that parents who are considering this intervention have plenty of time to consider all aspects and the opportunity for in depth discussion.

Rates of loss of heterozygosity and mitotic recombination in NF2 schwannomas, sporadic vestibular schwannomas and schwannomatosis schwannomas.

Biallelic inactivation of the NF2 gene occurs in the majority of schwannomas. This usually involves a combination of a point mutation or multiexon deletion, in conjunction with either a second point mutation or loss of heterozygosity (LOH). We have performed DNA sequence and dosage analysis of the NF2 gene in a panel of 239 schwannoma tumours: 97 neurofibromatosis type 2 (NF2)-related schwannomas, 104 sporadic vestibular schwannomas (VS) and 38 schwannomatosis-related schwannomas. In total, we identified germline NF2 mutations in 86 out of 97 (89%) NF2 patients and a second mutational event in 77 out of 97 (79%). LOH was by far the most common form of second hit. A combination of microsatellite analysis with either conventional comparative genomic hybridization (CGH) or multiplex ligation-dependent probe amplification (MLPA) identified mitotic recombination (MR) as the cause of LOH in 14 out of 72 (19%) total evaluable tumours. Among sporadic VS, at least one NF2 mutation was identified by sequence analysis or MLPA in 65 out of 98 (66%) tumours. LOH occurred in 54 out of 96 (56%) evaluable tumours, but MR only accounted for 5 out of 77 (6%) tested. LOH was present in 28 out of 34 (82%) schwannomatosis-related schwannomas. In all eight patients who had previously tested positive for a germline SMARCB1 mutation, this involved loss of the whole, or part of the long arm, of chromosome 22. In contrast, 5 out of 22 (23%) tumours from patients with no germline SMARCB1 mutation exhibited MR. High-resolution Affymetrix SNP6 genotyping and copy number (CN) analysis (Affymetrix, Santa Clara, CA, USA) were used to determine the chromosomal breakpoint locations in tumours with MR. A range of unique recombination sites, spanning approximately 11.4 Mb, were identified. This study shows that MR is a mechanism of LOH in NF2 and SMARCB1-negative schwannomatosis-related schwannomas, occurring less frequently in sporadic VS. We found no evidence of MR in SMARCB1-positive schwannomatosis, suggesting that susceptibility to MR varies according to the disease context.

Vestibular schwannoma: role of conservative management.

OBJECTIVE: To assess the outcome of conservative management of vestibular schwannoma. STUDY DESIGN: Observational study. SETTING: Tertiary referral centre. PATIENTS: Four hundred and thirty-six patients with vestibular schwannoma (490 tumours), including 327 sporadic tumours and 163 tumours in 109 patients with neurofibromatosis type two. MAIN OUTCOME MEASURES: The relationship of tumour growth to tumour size at presentation, and to certain demographic features. RESULTS: The initial tumour size was significantly larger in the neurofibromatosis type two group (11 mm) than in the sporadic vestibular schwannoma group (5.1 mm). In both groups, 68 per cent of tumours did not grow during follow up (mean 3.6 years; range one to 14 years). The mean growth rate was 1.1 mm/year (range 0-15 mm/year) for sporadic tumours and 1.7 mm/year (range 0-18 mm/year) for neurofibromatosis type two tumours. The tumour growth rate correlated positively with tumour size in the sporadic tumour group, and correlated negatively with age in the neurofibromatosis type two group. CONCLUSION: Two-thirds of vestibular schwannomas did not grow. Radiological surveillance is an acceptable approach in carefully selected patients. Once a sporadic vestibular schwannoma reaches 2 cm in intracranial diameter, it is likely to continue growing. We do not recommend conservative management for sporadic tumours with an intracranial diameter of 1.5 cm or more. Vestibular schwannoma management is more complex in patients with neurofibromatosis type two.

Trigeminal schwannomas.

Trigeminal schwannomas are the second most common intracranial schwannoma. They may occur sporadically or in association with neurofibromatosis type 2. The vast majority are benign in nature although malignancies have been reported. They may present with a range of symptoms because of their variable locations in areas with multiple differing functional activities. There is little understanding of the natural history of these tumours, and the choice of treatment includes surgery, stereotactic radiosurgery and fractionated radiotherapy. This article reviews the management options and outcomes. The incidence of recurrence and the time interval following treatment to recurrence is unpredictable.

Enterogenous cysts of the cerebellopontine angle: short review illustrated by two new patients.

Intracranial enterogenous cysts are an uncommon entity rarely found in the midline within the posterior cranial fossa. The occurrence of an enterogenous cyst in the cerebellopontine angle is exceptional. We present two new cases of cerebellopontine angle (CPA) enterogenous cysts and review the literature to clarify the diagnosis and the management of these lesions. Eighteen cases of CPA intradural enterogenous cysts have been reported to date, including the two cases presented in this article. All of them were symptomatic and underwent surgical treatment. After surgery, the symptomatic recurrence occurred in 31% of the patients, most of which had partial excision. Considering our patients and the published cases in the literature we suggest that the aim of surgery should be total removal of cyst and its content whenever possible. When partial resection of the cyst is performed, we recommend long-term clinical and neuroradiological follow-up.

A protocol for isolating Xenopus oocyte nuclear envelope for visualization and characterization by scanning electron microscopy (SEM) or transmission electron microscopy (TEM).

This protocol details methods for the isolation of oocyte nuclear envelopes (NEs) from the African clawed toad Xenopus laevis, immunogold labeling of component proteins and subsequent visualization by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). This procedure involves the initial removal of the ovaries from mature female X. laevis, the dissection of individual oocytes, then the manual isolation of the giant nucleus and subsequent preparation for high-resolution visualization. Unlike light microscopy, and its derivative technologies, electron microscopy enables 3-5 nm resolution of nuclear structures, thereby giving unrivalled opportunities for investigation and immunological characterization in situ of nuclear structures and their structural associations. There are a number of stages where samples can be stored, although we recommend that this protocol take no longer than 2 d. Samples processed for FESEM can be stored for weeks under vacuum, allowing considerable time for image acquisition.

Generation of cell-free extracts of Xenopus eggs and demembranated sperm chromatin for the assembly and isolation of in vitro-formed nuclei for Western blotting and scanning electron microscopy (SEM).

This protocol details methods for the generation of cell-free extracts and DNA templates from the eggs and sperm chromatin, respectively, of the clawed toad Xenopus laevis. We have used this system with scanning electron microscopy (SEM), as detailed herein, to analyze the biochemical requirements and structural pathways for the biogenesis of eukaryotic nuclear envelopes (NEs) and nuclear pore complexes (NPCs). This protocol requires access to female frogs, which are induced to lay eggs, and a male frog, which is killed for preparation of the sperm chromatin. Egg extracts should be prepared in 1 d and can be stored for many months at -80 degrees C. Demembranated sperm chromatin should take only approximately 2-3 h to prepare and can be stored at -80 degrees C almost indefinitely. The time required for assembly of structurally and functionally competent nuclei in vitro depends largely on the quality of the cell-free extracts and, therefore, must be determined for each extract preparation.

Visualization of the nucleus and nuclear envelope in situ by SEM in tissue culture cells.

Our previous work characterizing the biogenesis and structural integrity of the nuclear envelope and nuclear pore complexes (NPCs) has been based on amphibian material but has recently progressed into the analysis of tissue-culture cells. This protocol describes methods for the high resolution visualization, by field-emission scanning electron microscopy (FESEM), of the nucleus and associated structures in tissue culture cells. Imaging by fluorescence light microscopy shows general nuclear and NPC information at a resolution of approximately 200 nm, in contrast to the 3-5 nm resolution provided by FESEM or transmission electron microscopy (TEM), which generates detail at the macromolecular level. The protocols described here are applicable to all tissue culture cell lines tested to date (HeLa, A6, DLD, XTC and NIH 3T3). The processed cells can be stored long term under vacuum. The protocol can be completed in 5 d, including 3 d for cell growth, 1 d for processing and 1 d for imaging.

Vestibular schwannoma management: What is the 'best' option?

There is an abundance of medical literature describing the management options for vestibular schwannomas. However, the lack of high quality clinical trials means that, for any individual patient, the decision is often based on the clinician's personal biases. The management options that are available are conservative treatment, surgery, single-dose stereotactic radiosurgery and fractionated radiotherapy. In this review, we set out what the aims of managing a vestibular schwannoma should be and compare how these different treatment modalities perform. The particular objectives of tumour control, cranial nerve preservation, prevention of malignancy, quality of life and cost-effectiveness are discussed. It remains difficult to differentiate between these methods when more than one is suitable; the literature confirms that they are all safe and effective, but the decision must be the patient's, based on their individual priorities. This review should equip the clinician to provide an informed overview of the options.

Generic waiting lists for routine spinal surgery.

National Health Service Hospitals are under pressure to reduce waiting lists within the constraints of a limited infrastructure. We implemented two systems to reduce waiting times for elective non-complex spinal surgery. The first of these was the introduction of managed generic waiting lists for both initial outpatient appointments and subsequent surgery. Thereafter, the MRI booking system was integrated with outpatient review appointments. Times from referral to first outpatient appointment and from scan to outpatient review and time on waiting list for surgery were analysed before and after implementation of these changes. Despite constant unit capacity there was a global decrease in waiting times. Before introduction of the generic waiting list, 37% of listed patients waited for more than 9 months; this figure fell to zero. Time from scan to outpatient review was 185 days before integration, 30 days after. Changes of this sort demand a quorum of consultants who will accept each others' recommendations. The generic waiting list will have impact only when there are large disparities in waiting times for different consultants. Targets are met at the expense of continuity of care.

Remote hypertensive intracerebral haematoma following clipping of an intracranial aneurysm.

We report a case of a 58-year-old woman who presented with an aneurysmal subarachnoid haemorrhage. Immediately following clipping of this aneurysm, she had a spontaneous hypertensive bleed in the contralateral hemisphere. Although very unusual, hypertensive episodes following aneurysmal subarachnoid haemorrhage must carry a risk of such an intracranial event.

The Mycobacterium avium-intracellulare complex dnaB locus and protein intein splicing.

Intein is a protein sequence mebedded in-frame within a precursor protein and is posttranslationally excised by a self-catalytic protein splicing process. Protein splicing is believed to follow a pathway requiring Cys, Ser, or Thr residues at the intein N-terminus and substitutions other than Cys, Ser, or Thr residues prevent splicing. We show that the dnaB locus in some strains of M. avium-intracellulare complex (MAC) contains intein and that the intein N-terminal amino acid is Ala [Ala-type]. We demonstrate that the M. avium DnaB precursor protein undergoes posttranslational proteolytic processing producing proteins corresponding to the sizes of the DnaB and intein. Further, by Western analysis we detect a protein corresponding to the size of the spliced DnaB protein in MAC cell extracts. Together, these results indicate that the Ala-type MAC DnaB inteins can splice and provide another example that points to an interesting alternative splicing mechanism (Southworth, M. W., Benner, J., and Perler, F. B., EMBO J. 19, 5019-5026, 2000).

Ran alters nuclear pore complex conformation.

Transport across the nuclear membranes occurs through the nuclear pore complex (NPC), and is mediated by soluble transport factors including Ran, a small GTPase that is generally GDP-bound during import and GTP-bound for export. The dynamic nature of the NPC structure suggests a possible active role for it in driving translocation. Here we show that RanGTP but not RanGDP causes alterations of NPC structure when injected into the cytoplasm of Xenopus oocytes, including compaction of the NPC and extension of the cytoplasmic filaments. RanGTP caused accumulation of nucleoplasmin-gold along the length of extended cytoplasmic filaments, whereas RanGDP caused accumulation around the cytoplasmic rim of the NPC. This suggests a possible role for Ran in altering the conformation of the cytoplasmic filaments during transport.