Neurofibromatosis 2 in the pediatric population

Introduction to phacomatoses (neurocutaneous disorders) in childhood

The Dutch ophthalmologist, Jan van der Hoeve, first introduced the terms phakoma/phakomata (from the old Greek word "ϕαχοσ" = lentil, spot, lens-shaped) to define similar retinal lesions recorded in tuberous sclerosis (1920) and in neurofibromatosis (1923). He later applied this concept: (a) to similar lesions in other organs (e.g. brain, heart and kidneys) (1932) and (b) to other disorders (i.e. von Hippel-Lindau disease and Sturge-Weber syndrome) (1933), and coined the term phakomatoses. At the same time, the American neurologist Paul Ivan Yakovlev and psychiatrist Riley H. Guthrie (1931) established the key role of nervous systems and skin manifestations in these conditions and proposed to name them neurocutaneous syndromes (or ectodermoses, to explain the pathogenesis). The Belgian pathologist, Ludo van Bogaert, came to similar conclusions (1935), but used the term neuro-ectodermal dysplasias. In the 1980s, the American paediatric neurologist Manuel R. Gomez introduced the concept of "hamartia/hamartoma" instead of phakoma/phakomata. "Genodermatoses" and "neurocristopathies" were alternative terms still used to define these conditions. Nowadays, however, the most acclaimed terms are "phacomatoses" and "neurocutaneous disorders", which are used interchangeably. Phacomatoses are a heterogeneous group of conditions (mainly) affecting the skin (with congenital pigmentary/vascular abnormalities and/or tumours), the central and peripheral nervous system (with congenital abnormalities and/or tumours) and the eye (with variable abnormalities). Manifestations may involve many other organs or systems including the heart, vessels, lungs, kidneys and bones. Pathogenically, they are explained by interplays between intra- and extra-neuronal signalling pathways encompassing receptor-to-protein and protein-to-protein cascades involving RAS, MAPK/MEK, ERK, mTOR, RHOA, PI3K/AKT, PTEN, GNAQ and GNA11 pathways, which shed light also to phenotypic variability and overlapping. We hereby review the history, classification, genomics, clinical manifestations, diagnostic criteria, surveillance protocols and therapies, in phacomatoses: (1) predisposing to development of tumours (i.e. the neurofibromatoses and allelic/similar disorders and schwannomatosis; tuberous sclerosis complex; Gorlin-Goltz and Lhermitte-Duclos-Cowden syndromes); (2) with vascular malformations (i.e. Sturge-Weber and Klippel-Trenaunay syndromes; megalencephaly/microcephaly-capillary malformation syndromes; CLOVES, Wyburn-Mason and mixed vascular nevus syndromes; blue rubber bleb nevus syndrome; hereditary haemorrhagic telangiectasia); (3) with vascular tumours (von Hippel-Lindau disease; PHACE(S)); (4) with pigmentary/connective tissue mosaicism (incontinentia pigmenti; pigmentary/Ito mosaicism; mTOR-related megalencephaly/focal cortical dysplasia/pigmentary mosaicism; RHOA-related ectodermal dysplasia; neurocutaneous melanocytosis; epidermal/papular spilus/Becker nevi syndromes; PENS and LEOPARD syndromes; encephalocraniocutaneous lipomatosis; lipoid proteinosis); (5) with dermal dysplasia (cerebellotrigeminal dermal dysplasia); and (6) with twin spotting or similar phenomena (phacomatosis pigmentovascularis and pigmentokeratotica; and cutis tricolor).

Age at Onset and Presenting Symptoms of Neurofibromatosis Type 2 as Prognostic Factors for Clinical Course of Vestibular Schwannomas

The presenting symptoms of the tumor suppressor gene syndrome neurofibromatosis type 2 (NF2) are often non-specific and unrelated to the disease hallmark bilateral vestibular schwannomas (VS). However, age at onset and presenting symptoms may have predictive values for the clinical course of VS. In this retrospective single-center study, we addressed this issue by reviewing 106 patients with 194 VS. Presenting symptoms attributable to VS commonly occur in 87% of adults and 31% of children. Age at onset significantly correlates with tumor volumes at presentation (p = 0.034). In addition, age at onset significantly correlates with pure-tone average (p = 0.0001), speech discrimination scores (p = 0.001), age at beginning of hearing loss (p = 0.0001), age at deafness (p = 0.0001), and age at first surgery (p = 0.0001). Patients presenting with VS related symptoms had significantly (p < 0.05) worse hearing values at presentation and after surgery. These patients also exhibited higher growth rates and tumor volumes compared to patients with non-VS related presenting symptoms, but this difference did not reach the significance level of p < 0.05. Due to the late appearance of these symptoms, the time of beginning hearing loss, surgery and deafness is significantly delayed (p < 0.05) compared to patients not presenting with VS. In summary, age at onset and type of presenting symptom provide excellent prognostic parameters for predicting VS- and hearing-related clinical course.

Neurofibromatosis Type 2-Related Eye Disease Correlated With Genetic Severity Type

OBJECTIVE

Neurofibromatosis type 2 (NF2) is an uncommon but well-recognized disorder characterized by multiple schwannomas and meningiomas. Adults typically present with hearing loss and balance disturbance, and children with ocular, dermatological, and neurological signs. Clinical diagnosis is confirmed by neuroimaging and genetic testing. Although ophthalmic features are present in patients with NF2, there are no reports correlating genetic severity subtypes with ophthalmic involvement.

METHODS

We retrospectively reviewed longitudinal ophthalmological data of 83 patients with NF2, with known genetic severity subtype, to determine visual function over time. We created a scoring system (Oxford NF2 Ophthalmic Score [ONOS]) to quantify visually debilitating pathology.

RESULTS

The prevalence of optic atrophy, combined hamartomas, cataract, and epiretinal membranes significantly increased with genetic severity. Median age of survival to visual acuity worse than 1.0 logarithm of minimum angle of resolution in one eye significantly decreased with genetic severity and was 38 years in the genetically severe group, 49 years in moderate classics, 64 years in mild classics, and 84 years in the tissue mosaics. In the genetically severe, the visually damaging pathologies were largely untreatable. The ONOS correlated with genetic severity longitudinally and cross-sectionally.

CONCLUSIONS

Mutations associated with severe systemic disease result in greater visual morbidity at an earlier age. Those with tissue mosaicism are unlikely to have visually debilitating pathology secondary to NF2. Potentially treatable sources of damage to vision, however, affect all groups and must be identified early and treated effectively to retain useful vision throughout life.

A Prospective Evaluation of Swallowing and Speech in Patients with Neurofibromatosis Type 2

Objective  Neurofibromatosis type 2 (NF2) patients report that swallowing and speech problems significantly affect their quality of life, but the etiology of these phenomena is poorly understood. Swallowing and speech deficits may arise due to the neuropathy of involved nerves, due to posterior fossa tumor growth, or as iatrogenic effects from neurosurgical procedures to remove these tumors. This study aims to identify the natural history of swallowing and speech deficits in an NF2 cohort and to characterize the factors that may lead to those deficits. Methods  Subjects ( n  = 168) were enrolled in a prospective, longitudinal study of NF2 with yearly imaging and clinical exams. The patients completed a self-reported questionnaire that included responses regarding subjective swallowing and speech dysfunction. A formal speech-language pathology evaluation and modified barium swallow (MBS) study (reported as American Speech-Language Hearing Association [ASHA] swallowing independency score from 1 through 7) was obtained when a speech/swallowing deficit was reported on the questionnaire. Results  Of the 168 enrolled subjects, 55 (33%, median age = 31 years) reported subjective speech and/or swallowing deficits. These patients underwent one ( n  = 37) or multiple ( n  = 18) MBS studies during 44.8 ± 10.4 months follow-up. During MBS, a majority demonstrated near-normal swallowing (ASHA score >6, 82%), and no evidence of aspiration (aspiration/laryngeal penetration score = 1, 96%). Prior to initial MBS consultation, 38 (69%) patients had undergone relevant neurosurgical procedures. In those with recent (<1 week) posterior fossa surgery ( n  = 12), 2 (17%) patients had severe dysphagia and high aspiration risk on postoperative MBS. Both of these patients recovered to functionally independent swallowing status. Unilateral ( n  = 10) or bilateral ( n  = 6) tongue deficits unrelated to previous history suggestive of hypoglossal nerve injury were detected on clinical examination. There was a correlation between the presence of dysarthria and tongue deficits and tumors associated with the hypoglossal canal noted on imaging. Conclusion  A large proportion of patients with NF2 report speech and swallow deficits that are not evident on objective measurements. We also found hypoglossal neuropathy unrelated to prior surgical interventions. Our findings suggest that swallowing and speech problems in NF2 are associated with lower cranial nerve neuropathy, some due to compressive effects of posterior fossa tumors. Adaptation over the course of the disease allows for the compensation of these deficits and subsequent normal findings on objective testing.

Early Genetic Diagnosis of Neurofibromatosis Type 2 From Skin Plaque Plexiform Schwannomas in Childhood

Importance

Neurofibromatosis type 2 (NF2) is a devastating genetic condition characterized by the development of multiple tumors of the nervous system. An early diagnosis of individuals with NF2 would facilitate treatment and reduction of disease impact because most severe effects of the disease do not usually develop before adolescence. Little attention has traditionally been paid to dermatological signs in NF2. However, skin plaques are commonly seen in patients with NF2, normally appearing either at birth or early childhood, providing an opportunity for early NF2 detection and testing.

Objective

To determine the clinical utility of skin plaque identification and characterization in children for reaching an early diagnosis of patients with NF2 and to evaluate their molecular pathogenesis and their use in the genetic diagnostics of NF2.

Design, Setting, and Participants

Diagnostic test study by the histological and genetic characterization of skin plaques from patients with NF2. Patients were 7 individuals with NF2 or clinical suspicion of NF2 treated at the Spanish Reference Center on Phakomatoses.

Main Outcomes and Measures

Histological evaluation of all skin plaques was performed. Fresh skin plaques were cultured to obtain Schwann cells and the NF2 gene was genetically analyzed. For all 7 patients, NF2 clinical history was reviewed.

Results

In all 7 patients (4 male and 3 female), all skin plaques analyzed were histologically characterized as plexiform schwannomas. Genetic analysis of primary Schwann cell cultures derived from them allowed the identification of a constitutional and a somatic NF2 mutation. Genetic testing allowed the early diagnosis of NF2 in a child only exhibiting the presence of skin plaques. Most of the patients with NF2 analyzed had an early presentation of skin plaques and a severe NF2 phenotype.

Conclusions and Relevance

This work emphasizes the clinical utility of a careful dermatological inspection and the correct identification of skin plaques in children for an early diagnosis of NF2. We show for the first time that Schwann cells derived from skin plaque plexiform schwannomas bear the double inactivation of the NF2 gene and thus constitute an excellent source of tissue for genetic testing, especially in the context of mosaicism.

Diagnosis of sporadic neurofibromatosis type 2 in the paediatric population

OBJECTIVE

Onset of symptoms in severe sporadic neurofibromatosis type 2 (NF2) is typically within childhood; however, there is poor awareness of presenting features in young children, potentially resulting in delayed diagnosis and poorer outcome. We have reviewed presentation of sporadic paediatric NF2 to raise awareness of early features, highlighting those requiring further investigation.

DESIGN

Patients diagnosed with NF2 at age ≤16 and seen between 2012 and 2015 were notified via the British Paediatric Neurology Surveillance Unit or identified through the English NF2 service.

RESULTS

Epidemiological data estimate that 1 in 110 611 births are affected with childhood-onset NF2. Notes of 32 patients with sporadic NF2 were reviewed. Of those presenting under the age of 5, 89% (17/19) had ocular, 74% (14/19) dermatological and 58% (11/19) neurological signs; in 84% (16/19) features were multisystemic. Sixty-six per cent (21/32) had ≥1 atypical feature, including cerebellar hypoplasia in three cases (9%) and focal cortical dysplasia in five out of seven seizure-related presentations. Five cases presented with a sometimes transient or intermittent cranial nerve mononeuropathy. The mean delay to diagnosis was 3.16 years; in eight cases (25%) this exceeded 6 years. Most significant delay occurred in mononeuropathy, ophthalmological and/or seizure presentations, with a mean delay of 3, 4.5 and 6 years, respectively. Eighty-four per cent (27/32) of cases needed intervention in childhood.

CONCLUSIONS

All non-vestibular schwannoma NF2 presentations in childhood had significant diagnostic delay. We emphasise the importance of detailed assessment of skin and eyes in unusual presentations and propose an aide to prompt timely referral to specialist services.

Monitoring of optic nerve function in Neurofibromatosis 2 children with optic nerve sheath meningiomas using multifocal visual evoked potentials

Monitoring optic nerve sheath meningiomas (ONSM) in Neurofibromatosis type 2 (NF2) patients remains difficult. Other ocular manifestations of NF2 may obscure ophthalmic assessment of optic nerve function in these patients. Serial magnetic resonance imaging (MRI) used to assess the optic nerve is not without limitations, being expensive and often requiring general anaesthetic in children, with associated risks. This study was undertaken to describe the use of multifocal visual evoked potentials (multifocal VEP, mfVEP) in the regular monitoring of NF2 patients with ONSM. This study involved three NF2 patients with ONSM who undertook mfVEP testing at an academic ophthalmic centre. Same day mfVEP and routine ophthalmic testing were undertaken. Topographical function of the optic nerve was assessed, utilising tools such as asymmetry deviation and accumap severity index. Results were assessed alongside MRI and visual acuity (VA). From the three patients, five eyes had ONSMs, of which two caused unilateral blindness. The remaining three affected eyes had initial VAs 6/6, 6/24, and 6/18. Over follow up, ranging from 5 to 12 years, all tumours progressed, and VA declined for all patients. Multifocal VEP detected optic nerve functional loss corresponding with visual decline. This case series suggests mfVEP is effective in the objective topographic monitoring of optic nerve function in NF2 patients with ONSM. Due also to its safety in a paediatric population, the test may be considered in the routine monitoring of these patients, to be used to assist regular ophthalmic review and MRI scans.

Childhood neurofibromatosis type 2 (NF2) and related disorders: from bench to bedside and biologically targeted therapies

Neurofibromatosis type 2 [NF2; MIM # 101000] is an autosomal dominant disorder characterised by the occurrence of vestibular schwannomas (VSs), schwannomas of other cranial, spinal and cutaneous nerves, cranial and spinal meningiomas and/or other central nervous system (CNS) tumours (e.g., ependymomas, astrocytomas). Additional features include early onset cataracts, optic nerve sheath meningiomas, retinal hamartomas, dermal schwannomas (i.e., NF2-plaques), and (few) café-au-lait spots. Clinically, NF2 children fall into two main groups: (1) congenital NF2 - with bilateral VSs detected as early as the first days to months of life, which can be stable/asymptomatic for one-two decades and suddenly progress; and (2) severe pre-pubertal (Wishart type) NF2- with multiple (and rapidly progressive) CNS tumours other-than-VS, which usually present first, years before VSs [vs. the classical adult (Gardner type) NF2, with bilateral VSs presenting in young adulthood, sometimes as the only disease feature]. Some individuals can develop unilateral VS associated with ipsilateral meningiomas or multiple schwannomas localised to one part of the peripheral nervous system [i.e., mosaic NF2] or multiple non-VS, non-intradermal cranial, spinal and peripheral schwannomas (histologically proven) [schwannomatosis]. NF2 is caused by mutations in the NF2 gene at chromosome 22q12.1, which encodes for a protein called merlin or schwannomin, most similar to the exrin-readixin-moesin (ERM) proteins; mosaicNF2 is due to mosaic phenomena for the NF2 gene, whilst schwannomatosis is caused by coupled germ-line and mosaic mutations either in the SMARCB1 gene [SWNTS1; MIM # 162091] or the LZTR1 gene [SWNTS2; MIM # 615670] both falling within the 22q region and the NF2 gene. Data driven from in vitro and animal studies on the merlin pathway [e.g., post-translational and upstream/downstream regulation] allowed biologically targeted treatment strategies [e.g., Lapatinib, Erlotinib, Bevacizumab] aimed to multiple tumour shrinkage and/or regression and tumour arrest of progression with functional improvement.

Neurofibromatosis Type 2

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder (incidence 1:33 000-40 000) characterized by formation of central nervous system tumors, due to mutation in the NF2 gene on chromosome 22q12. Vestibular schwannomas are the hallmark lesion, affecting 95% of individuals and typically occur bilaterally. Schwannomas commonly occur on other nerves intracranially and in the spinal compartment, along with meningiomas, ependymomas, and gliomas. Although histologically benign, tumors are associated with significant morbidity due to multiple problems including hearing and vision loss, gait abnormalities, paralysis, pain, and seizures. Risk of early mortality from brainstem compression and other complications is significant. Severity of disease is higher when NF2 presents during childhood. Children have a more variable presentation, which can be associated with significant delays in recognition of the condition. Careful examination of the skin and eyes can identify important clinical signs of NF2 during childhood, allowing timely initiation of disease-specific surveillance and treatment. Monitoring for complications comprises clinical evaluation, along with functional testing including audiology and serial neuroimaging, which together inform decisions regarding treatment. Evidence for disease-specific medical treatment options is increasing, nevertheless most patients will benefit from multimodal treatment including surgery during their lifetime. Patient enrolment in international natural history and treatment trials offers the best opportunity to accelerate our understanding of the complications and optimal treatment of NF2, with a view to improving outcomes for all affected individuals.

Diagnosis, Management, and New Therapeutic Options in Childhood Neurofibromatosis Type 2 and Related Forms

Neurofibromatosis type 2 (NF2; MIM # 101000) is an autosomal dominant disorder characterized by the development of vestibular schwannomas (VSs); schwannomas of other cranial, spinal, and cutaneous nerves; cranial and spinal meningiomas or other central nervous system tumors (eg, ependymomas and astrocytomas) or both. Additional features include eye (eg, early onset cataracts, optic nerve sheath meningiomas, retinal or pigment epithelial hamartomas or both, and epithelial retinal membranes) and skin abnormalities (eg, flat dermal [NF2 plaques] or spherical subcutaneous nodular schwannomas or both, and few, atypical café-au-lait spots). Clinically, children with NF2 fall into 2 main groups: (1) congenital NF2 with bilateral VSs detected as early as the first days to months of life, which can be stable or asymptomatic for 1-2 decades and suddenly progress; and (2) severe prepubertal (Wishart type) NF2 with multiple (and rapidly progressive) central nervous system tumors other-than-VS, which usually presents first, years before VSs, both associated with more marked skin and eye involvement (vs the classical mild adult [Gardner type] NF2, with bilateral VSs presenting in young adulthood, sometimes as the only disease feature). Individuals manifesting unilateral VS associated with ipsilateral meningiomas or multiple schwannomas localized to a part of the peripheral nervous system have mosaic or segmental NF2; individuals developing multiple nonVS, nonintradermal cranial, spinal, and peripheral schwannomas (histologically proven) have schwannomatosis (SWNTS). NF2 is caused by mutations in the NF2 gene at chromosome 22q12.1, which encodes for a protein called merlin or schwannomin, most similar to the exrin-readixin-moesin proteins; mosaic or segmental NF2 is because of mosaic phenomena for the NF2 gene, whereas SWNTS is caused by germline and possibly mosaic mutations either in the SMARCB1 gene (SWNTS1; MIM # 162091) or the LZTR1 gene (SWNTS2; MIM # 615670), both falling within the 22q region. Data driven from in vitro and animal studies on the merlin pathway allowed biologically targeted treatment strategies (employing Lapatinib, Erlotinib, Everolimus, Picropodophyllin, OSU.03012, Imatinib, Sorafenib, and Bevacizumab) aimed at multiple tumor shrinkage or regression or both and tumor arrest of progression with functional improvement.

[Early type 2 neurofibromatosis and congenital retinal hamartoma]

Neurofibromatosis type 2 (NF2) is a heritable syndrome characterized by multifocal proliferation of neural crest-derived cells. It has long been regarded as an adolescent- and adult-onset disease. We report here on a case of a 6-year-old girl with infantile-onset clinical signs. The girl, who had a history of amblyopia and congenital retinal hamartoma, presented with rough dimness of visual acuity. Cerebral magnetic resonance imaging found a left voluminous fronto-temporal tumor including the chiasma and optical nerves. Vestibular and cervical nerve schwannomas were also found. She underwent a first neurosurgical partial excision and histopathology revealed meningioma. Postoperative radiotherapy was necessary due to a secondary increase of the tumor size. Subsequent molecular testing revealed a NF2 gene abnormality. NF2 can become evident in infancy but clinical early symptomatology is often different: ocular symptoms and neurological problems are common. There is no consensus on the treatment of tumors involving the central and peripheral nervous system, abstention being usual. In case of severe signs, surgery and radiotherapy can be proposed. The diagnosis of a hamartoma must lead to multidisciplinary follow-up.

[Type 2 neurofibromatosis: intergenerational differences in genetic and clinical expression]

INTRODUCTION

Neurofibromatosis type 2 (NF2) is a rare dominantly inherited disease. Its clinical presentation can be completely different in children and adults and early diagnosis is often difficult. The NF2 gene molecular analysis can help for diagnosis, but its result can be negative in case of NF2 mosaicism.

OBSERVATIONS

We report the case of a 43-year-old man who had developed a severe phenotype with bilateral vestibular schwannomas at 19 years of age. His son presented a retinal hamartoma with loss of vision in his right eye at 2 months of age. At 9 years of age, asymptomatic schwannomas of the cranial nerves were discovered: cranial nerves X (left), XI (left), and VIII (bilateral). Partial constitutional NF2 deletion (from exons 2-7) was detected in his son. The deletion was not detectable in the DNA blood of his father and we strongly suspect a mosaic form of NF2.

CONCLUSION

Ophthalmological manifestations can be the initial sign of NF2 in childhood. These features must be actively sought during the first year of life in individuals at risk of NF2. NF2 mosaicism is often described as a mild form of NF2 with a very low risk of transmission to the carrier's children. We show that NF2 mosaicism can sometimes develop severe NF2 symptoms and we confirm that the transmission risk to the offspring depends on the proportion of zygotes carrying the mutation. NF2 remains a life-limiting and life-spoiling condition. Early diagnosis is necessary to prevent complications and the follow-up of NF2 patients must be organized throughout life in specialty centers.

Clinical course of vestibular schwannoma in pediatric neurofibromatosis Type 2

OBJECT

Neurofibromatosis Type 2 (NF2) is an autosomal-dominant inherited disease, characterized by multiple neoplasia syndromes, including meningioma, schwannoma, glioma, and ependymoma. In this report, the authors present their clinical experience with pediatric NF2 patients. In particular, they focused on the clinical course of vestibular schwannoma (VS), including the natural growth rate, tumor control, and functional hearing outcomes.

METHODS

From May 1988 to June 2012, the authors recruited patients who were younger than 18 years and fulfilled the Manchester criteria. In total, 25 patients were enrolled in this study. The authors analyzed the clinical course of these patients. In addition, they measured the natural growth rate of VS before any treatment in these children with NF2. Then, they evaluated the tumor control rate and functional hearing outcomes after the treatment of VS.

RESULTS

The mean age at the onset of NF2-related symptoms was 9.9 ± 4.5 years (mean ± SD, range 1-17 years). The mean age at the diagnosis of NF2 was 12.9 ± 2.9 years (range 5-17 years). The mean follow-up period was 89.3 months (range 12-311 months). As initial manifestations, nonvestibular symptoms were frequently observed in pediatric patients with NF2. The mean natural growth rate of VS was 0.33 ± 0.41 cm(3)/year (range 0-1.35 cm(3)/year). The tumor control rate of VS was 35.3% at 3 years after Gamma Knife surgery (GKS). The actuarial rate of useful hearing preservation was 67% in the 1st year and 53% in the 5th year after GKS.

CONCLUSIONS

Clinical manifestations in children with NF2 were highly variable, compared with their adult counterparts. The natural growth rate of VS in children is slow, and this oncological feature may explain the diverse clinical manifestations besides vestibular symptoms in children with NF2. The treatment outcome of GKS for VS in children with NF2 was not favorable compared with previous reports of affected adults.

Hearing loss and enlarged internal auditory canal in children

INTRODUCTION

Among the temporal bone abnormalities that can be found in the etiological study of paediatric sensorineural hearing loss (SNHL) by imaging techniques, those related to the internal auditory canal (IAC) are the least frequent. The most prevalent of these abnormalities that is associated with SNHL is stenotic IAC due to its association with cochlear nerve deficiencies. Less frequent and less concomitant with SNHL is the finding of an enlarged IAC (>8mm).

METHODS

Retrospective and descriptive review of clinical associations, imaging, audiological patterns and treatment of 9 children with hearing loss and enlarged IAC in the period 1999 to 2012.

RESULTS

Two groups of patients are described. The first, without association with vestibulocochlear dysplasias, consisted of: 2 patients with SNHL without other temporal bone or systemic abnormalities, one with bilateral mixed HL from chromosome 18q deletion, one with a genetic X-linked DFN3 hearing loss, one with unilateral hearing loss in neurofibromatosis type 2 with bilateral acoustic neuroma, and one with unilateral hearing loss with cochlear nerve deficiency. The second group, with association with vestibulocochlear dysplasias, was comprised of: one patient with moderate bilateral mixed hearing loss in branchio-oto-renal syndrome, one with profound unilateral SNHL with recurrent meningitis, and another with profound bilateral SNHL with congenital hypothyroidism.

CONCLUSIONS

The presence of an enlarged IAC in children can be found in different clinical and audiological settings with relevancies that can range from life-threatening situations, such as recurrent meningitis, to isolated hearing loss with no other associations.

Pediatric cerebellopontine angle and internal auditory canal tumors: clinical article

OBJECT

The aim in this study was to describe the clinical presentation, differential diagnosis, and risk for neurofibromatosis Type 2 (NF2) in pediatric patients presenting with cerebellopontine angle (CPA) and internal auditory canal (IAC) tumors.

METHODS

The authors conducted a retrospective study at a tertiary care academic referral center. All patients with an age ≤ 18 years who had presented with an extraaxial CPA or IAC tumor between 1987 and 2012 were included in the study cohort. Data regarding symptoms, diagnosis, tumor characteristics, and NF2 status were collected and analyzed.

RESULTS

Sixty patients (55% female, 45% male) harboring 87 tumors were identified. The mean age at diagnosis was 12.8 years (median 14.0 years, range 0.9-18.9 years). Schwannomas were the most commonly identified lesions (57 of 87 tumors, including 52 vestibular, 3 facial, and 2 trigeminal schwannomas), followed by meningiomas (5 of 87) and epidermoid cysts (4 of 87). Six malignant tumors were diagnosed, including small-cell sarcoma, squamous cell carcinoma, malignant meningioma, atypical rhabdoid-teratoid tumor, endolymphatic sac tumor, and malignant ganglioglioma. Headache, followed by hearing loss and imbalance, was the most common presenting symptom, whereas dysphagia, otalgia, and facial pain were uncommon. Neurofibromatosis Type 2 was diagnosed in 20 (61%) of 33 patients with vestibular schwannoma (VS), while the other 13 patients (39%) had sporadic tumors. Nineteen of the 20 patients with NF2 met the diagnostic criteria for that disorder on initial presentation, and 15 of them presented with bilateral VS. At the last follow-up, 19 of the 20 patients subsequently diagnosed with NF2 demonstrated bilateral VSs, whereas 1 patient with a unilateral VS and multiple other NF2-associated tumors has yet to demonstrate a contralateral VS to date. Only 1 patient presenting with an isolated unilateral VS and no family history of NF2 demonstrated a contralateral VS on subsequent radiological screening.

CONCLUSIONS

Cerebellopontine angle and IAC tumors in the pediatric population are rare. There are several noteworthy differences between the adult and pediatric populations harboring these lesions. While VS is the most common pathology in both age groups, the lesion was found in only 60% of the pediatric patients in the present study. Unlike in adults, VSs in the pediatric population were associated with NF2 in over one-half of all cases. The majority of pediatric patients with NF2 fulfilled the diagnostic criteria at initial presentation; however, approximately 7% of patients presenting with a seemingly sporadic (no family history of NF2) unilateral VS will meet the criteria for NF2 later in life. Finally, malignancies account for a significantly higher percentage (10%) of cases among pediatric patients. These findings underscore the importance of early screening and close radiological follow-up and may be helpful in patient counseling.

Clinicopathologic assay of 15 tumor resections in a family with neurofibromatosis type 2

The objective of this study is the management of multiple family members with multiple neurofibromatosis type 2 (NF2) related tumors of the skull base that can be challenging, on purely technical, decision-making, and ethical levels. These issues are addressed in this manuscript based on an experience treating an unique large family with NF2. A retrospective chart review was performed, reviewing clinical, radiological, surgical, and pathological data. A unique family of 17 siblings, whose father was the proband as a sporadic mutation is reported. Over a 4-month period, five of eight affected siblings underwent 12 procedures for resection of 15 different NF2-related tumors. This single family experience of NF2-related skull base tumors underscores the importance of preservation of function and quality of life as the major determinants of treatment success.

Bevacizumab treatment for meningiomas in NF2: a retrospective analysis of 15 patients

Bevacizumab treatment can result in tumor shrinkage of progressive vestibular schwannomas in some neurofibromatosis 2 (NF2) patients but its effect on meningiomas has not been defined.

To determine the clinical activity of bevacizumab against NF2-related meningiomas, we measured changes in volume of meningiomas in NF2 patients who received bevacizumab for treatment of progressive vestibular schwannomas. A radiographic response was defined as a 20% decrease in tumor size by volumetric MRI analysis. In addition, we determined the expression pattern of growth factors associated with tumor angiogenesis in paraffin-embedded tissues from 26 unrelated meningiomas. A total of 48 meningiomas in 15 NF2 patients were included in this study with a median follow up time of 18 months. A volumetric radiographic response was seen in 29% of the meningiomas (14/48). Tumor shrinkage was not durable: the median duration of response was 3.7 months and the median time to progression was 15 months. There was no significant correlation between pre-treatment growth rate and meningioma response in regression models. Tissue analysis showed no correlation between tumor microvascular density and expression of VEGF pathway components. This data suggests that, in contrast to schwannomas, activation of VEGF pathway is not the primary driver of angiogenesis in meningiomas. Our results suggest that a minority of NF2-associated meningiomas shrink during bevacizumab therapy and that these responses were of short duration. These results are comparable to previous studies of bevacizumab in sporadic meningiomas.

Neurofibromatosis type 2 (NF2): diagnosis and management

Neurofibromatosis type 2 (NF2) is an autosomal dominant inherited tumor predisposition syndrome caused by mutations in the NF2 gene on chromosome 22. Affected individuals develop schwannomas typically involving both vestibular nerves leading to hearing loss and eventual deafness. Rehabilitation with brainstem implants and in some cases cochlear implants is improving this outcome. Schwannomas also occur on other cranial nerves, on spinal nerve roots and peripheral nerves, and intracutaneously as plaques. Cranial and spinal meningiomas and spinal ependymomas are other common tumors. Fifty to sixty percent of patients represent de novo mutations and as many as 33% of these are mosaic for the underlying disease causing mutation. Truncating mutations (nonsense, frameshift insertions/deletions) are the most frequent germline events and cause the most severe disease, whilst single and multiple exon deletions are common and are usually associated with milder NF2. Neurological deficits are a major feature of the condition and neurologists have a pivotal role in assigning symptoms to lesions and in managing neuropathies. NF2 represents a difficult management problem with most patients facing substantial morbidity and reduced life expectancy. Surgery remains the focus of current management although watchful waiting and occasionally radiation treatment have a role. We are seeing the advent of tailored drug therapies aimed at the genetic level and these are likely to provide huge improvements for this devastating, life-limiting condition.

Neurogenic tumors of soft tissue

Neurogenic tumors are an uncommon yet important category of soft tissue tumors in children and adolescents because of their frequent association with various genetic syndromes. The heterogeneous cellular composition of the peripheral nerve and the wide metaplastic capacity of the neural crest and its derivatives generate a variety of neoplasms with neurogenic differentiation. This article reviews the clinicopathologic features and differential diagnosis of neurogenic tumors in the first two decades of life, and highlights use of selected ancillary methods for diagnosis.

Consensus recommendations for current treatments and accelerating clinical trials for patients with neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome characterized by bilateral vestibular schwannomas (VS) which often result in deafness despite aggressive management. Meningiomas, ependymomas, and other cranial nerve and peripheral schwannomas are also commonly found in NF2 and collectively lead to major neurologic morbidity and mortality. Traditionally, the overall survival rate in patients with NF2 is estimated to be 38% at 20 years from diagnosis. Hence, there is a desperate need for new, effective therapies. Recent progress in understanding the molecular basis of NF2 related tumors has aided in the identification of potential therapeutic targets and emerging clinical therapies. In June 2010, representatives of the international NF2 research and clinical community convened under the leadership of Drs. D. Gareth Evans (University of Manchester) and Marco Giovannini (House Research Institute) to review the state of NF2 treatment and clinical trials. This manuscript summarizes the expert opinions about current treatments for NF2 associated tumors and recommendations for advancing therapies emerging from that meeting. The development of effective therapies for NF2 associated tumors has the potential for significant clinical advancement not only for patients with NF2 but for thousands of neuro-oncology patients afflicted with these tumors.

Therapeutics for childhood neurofibromatosis type 1 and type 2

OPINION STATEMENT

Neurofibromatosis type 1 (NF1) and type 2 (NF2) are genetically and medically distinct neurocutaneous disorders that are both associated with tumors affecting the central and peripheral nervous systems. NF1 has a frequency of 1 in 3,000, compared with 1 in 30,000 for NF2. Careful surveillance is important for both conditions, to allow early identification and treatment of complications. The most common and important problems in NF1 are cognitive impairment, optic pathway gliomas, plexiform neurofibromas, and orthopaedic issues. Early intervention and tailored educational programs are indicated for learning difficulties. Attention deficit hyperactivity disorder may be amenable to treatment with stimulant medication. A clinical trial is under way to evaluate lovastatin in the treatment of cognitive problems in children with NF1. Chemotherapy with vincristine and carboplatin is the current standard of care for symptomatic optic pathway gliomas, but new agents with improved efficacy are needed. Plexiform neurofibromas may be treated with surgery, but often recur. To date, no medical therapy has proven effective in limiting plexiform neurofibroma growth, but several candidate medications are under consideration in clinical trials. Malignant peripheral nerve sheath tumors may arise in preexisting plexiform neurofibromas, so changes in tumor growth or an increase in pain or focal neurologic deficit should prompt further investigation and early treatment with wide surgical resection, with or without adjuvant chemotherapy or radiotherapy. Specialist surgical intervention may be needed for scoliosis and tibial pseudoarthrosis. In NF2, surgical treatment remains a cornerstone of management for symptomatic progressive vestibular schwannomas, meningiomas, and spinal tumors. Vascular endothelial growth factor inhibitors show promise for the treatment of vestibular schwannomas, with the aim of delaying surgery, and other targeted molecular therapies are becoming available as investigational options. Hearing aids and brainstem and cochlear implants have a role in optimizing functional hearing in some patients. Specialist ophthalmology input should be arranged to monitor for ophthalmologic complications. A coordinated effort is needed to enroll NF1 and NF2 patients in international multicenter clinical trials of promising new pharmacologic agents. Genetic testing is useful for prenatal diagnosis and may be important in understanding individual responses to novel medical therapies in the future. Effective transition to adult services is important, considering the likelihood of further complications in the adult years.

Imaging tumors of the pediatric central nervous system

Primary tumors of the central nervous system (CNS) are the second most common neoplasms in children and the leading cause of death in this patient population. The primary objective of this article is to describe the most common pediatric brain tumors and to offer an overview of their respective imaging features, primarily on magnetic resonance imaging. Precise anatomic characterization is essential for developing an appropriate differential diagnosis. Once equipped with this critical information, physicians should be better able to make firm diagnoses, leading to improved disease management and patient outcomes in the setting of CNS tumors of childhood.

Brachium pontis stroke revealing neurofibromatosis type-2

NF2 is an autosomal dominant disorder with neuroectodermal dysplasia. Most patients present with characteristic clinical tumors during or beyond the adolescent age group. The diagnosis is mainly clinical. Vasculopathy is rarely associated with NF2. Vascular complication as the presenting symptom in NF-2 is unknown. We report a case of a 2-year-old child with no prior family history of neurofibromatosis presenting with ataxia and brain-stem stroke.

Multiple primary cranio-spinal tumours in a 13-year-old female with neurofibromatosis type 2 management strategy

INTRODUCTION

Neurofibromatosis type 2 (NF2) is an inherited, rare autosomal dominant syndrome characterised by the development of multiple benign cranial and spinal tumours, peripheral neuropathy, ophthalmological and cutaneous lesions. Herein, we report one case of NF2 treated with multivariate chemotherapy.

MATERIAL AND METHODS

A 13-year-old female presented with multiple cranio-spinal tumours in MRI. First symptoms were progressive changes in vision, left-sided paresis, unilateral sensorineural hearing loss, and left hypoglossal nerve paresis. The patient underwent palliative, partial surgical resection of the tumour which was located in a posterior fossa. Histopathological examination showed a psammomatous meningioma located near the great foramen and schwannomas of VIII nerve in the cerebello-pontine angle. Clinical and radiological examination revealed a rapid progression of the disease. As such, multivariate chemotherapy was used. The patient died 4 years after diagnosis.

CONCLUSION

NF2 patients with multiple tumours at diagnosis may not be treatable with surgery alone and, as a result, presentation with such a disease in childhood results in poor prognosis. The unification of management strategies in NF2 patients is highly desirable.

The diagnostic and clinical significance of café-au-lait macules

Café-au-lait, also referred to as café-au-lait spots or café-au-lait macules, present as well-circumscribed, evenly pigmented macules and patches that range in size from 1 to 2 mm to greater than 20 cm in greatest diameter. Café-au-lait are common in children. Although most café-au-lait present as 1 or 2 spots in an otherwise healthy child, the presence of multiple café-au-lait, large segmental café-au-lait, associated facial dysmorphism, other cutaneous anomalies, or unusual findings on physical examination should suggest the possibility of an associated syndrome. While neurofibromatosis type 1 is the most common syndrome seen in children with multiple café-au-lait, other syndromes associated with one or more café-au-lait include McCune-Albright syndrome, Legius syndrome, Noonan syndrome and other neuro-cardio-facialcutaneous syndromes, ring chromosome syndromes, and constitutional mismatch repair deficiency syndrome.

Management of the patient and family with neurofibromatosis 2: a consensus conference statement

A consensus conference on neurofibromatosis 2 (NF2) was held in 2002 at the request of the United Kingdom (UK) Neurofibromatosis Association, with particular emphasis on vestibular schwannoma (VS) surgery. NF2 patients should be managed at specialty treatment centres, whose staff has extensive experience with the disease. All NF2 patients and their families should have access to genetic testing because presymptomatic diagnosis improves the clinical management of the disease. Some clinical manifestations of NF2, such as ocular abnormalities, can be detected in infancy; therefore, clinical screening for at-risk members of NF2 families can start at birth, with the first magnetic resonance (MRI) scan at 10-12 years of age. Minimal interference, maintenance of quality of life, and conservation of function or auditory rehabilitation are the cornerstones of NF2 management, and the decision points to achieve these goals for patients with different clinical presentations are discussed.

Neurofibromatosis type 2

Neurofibromatosis type 2 is an autosomal-dominant multiple neoplasia syndrome that results from mutations in the NF2 tumour suppressor gene located on chromosome 22q. It has a frequency of one in 25,000 livebirths and nearly 100% penetrance by 60 years of age. Half of patients inherit a germline mutation from an affected parent and the remainder acquire a de novo mutation for neurofibromatosis type 2. Patients develop nervous system tumours (schwannomas, meningiomas, ependymomas, astrocytomas, and neurofibromas), peripheral neuropathy, ophthalmological lesions (cataracts, epiretinal membranes, and retinal hamartomas), and cutaneous lesions (skin tumours). Optimum treatment is multidisciplinary because of the complexities associated with management of the multiple, progressive, and protean lesions associated with the disorder. We review the molecular pathogenesis, genetics, clinical findings, and management strategies for neurofibromatosis type 2.

Allogeneic transplantation and the risk for transmission of genetic disease: the heritable cancer disorders

With the development of new approaches to transplantation therapy, such as those building upon the potential found in stem cells, it is vital to pursue a clear understanding of transplantation risks. Allogeneic transplantation presents risk for the transmission of disease of various types, including genetic disease. Predisposition to develop cancer is a feature of numerous genetic disorders, and it may be transmissible by transplantation. Some genetic disorders predisposing to cancer are remarkably common, either worldwide or in specific populations, and they could pose significant risk. Hence, to reduce risk to recipients, there is reason to exclude from donation those potential donors (including embryos) harboring certain germ-line mutations. However, the frequent absence of readily identifiable features might confound the effort to exclude those who harbor mutation. Thus, it is also important to consider the magnitude of risk that they represent. For some disorders, life-threatening cancer is highly likely to develop in those individuals born with germ-line mutation, but whether recipients would face the same risk from transplanted mutation is not always evident. Given the diversity of pathways that lead to cancer, there may be diverse factors that impact the likelihood for cancer to develop in the recipient, with some factors decreasing and others increasing the risk. One factor of special concern is the possibility that manipulation of donor cells, prior to transplantation, might introduce additional genetic or epigenetic abnormality, thereby increasing the risk.

Ophthalmologic findings and long-term course in patients with neurofibromatosis type 2

PURPOSE

To evaluate ophthalmologic findings and long-term course in patients with neurofibromatosis type 2 (NF2).

DESIGN

Retrospective observational case series.

METHODS

SETTING

Single-center institutional practice.

STUDY POPULATION

Thirty referred patients with NF2 were enrolled from 1991 to 2003 and underwent at least one thorough neuroophthalmologic examination. Follow-up of 23 patients ranged from 4.3 to 12.5 years.

MAIN OUTCOME MEASURES

Visual function, structural ocular abnormalities, onset and type of presenting NF2-related symptoms, and number of central nervous system tumors.

RESULTS

Initial symptoms for patients with early-onset NF2 mostly comprised ophthalmologic symptoms (n = 7) and lower motor neuron extremity weakness (n = 6), as opposed to eighth nerve impairment (n = 11) in late disease onset. NF2-specific ocular findings were noted in 83% of all patients (94% childhood onset; 67% adult onset): 67% had cataracts, 40% epiretinal membranes, 3% hamartoma, 13% disk gliomas, and 27% optic nerve sheath meningiomas. Only 14% in the childhood-onset group-as opposed to 78% in the adult-onset group-sustained visual acuity of 1.0 in both eyes at final examination. Significantly more patients with early onset of symptoms developed multiple central nervous system tumors (P = .004) and showed a higher amount of NF2-specific findings (P = .015).

CONCLUSIONS

Initial manifestations of NF2 differ between children and adults. NF2-specific ophthalmologic findings can help establish the diagnosis. Symptom onset at a young age is clearly a risk factor for marked disease progression. These patients should be carefully followed because survival rates have increased, and vision becomes increasingly important as the disease progresses.

Renal vascular disease in neurofibromatosis type 2: association or coincidence?

Neurofibromatosis type 2 (NF2) remains a challenging diagnosis in childhood where there may be no neurological involvement. A 12-month-old male in whom NF2 was suspected because of characteristic ophthalmological and cutaneous lesions is reported. Cranial MRI showed no tumours. A pathogenic mutation was identified on NF2 gene analysis. The child developed hypertension due to renal vascular disease. Although renal vascular disease is a recognized complication of neurofibromatosis type 1 (NF1), it has not been reported in NF2.

Genotype-phenotype correlations for nervous system tumors in neurofibromatosis 2: a population-based study

Neurofibromatosis 2 (NF2) is an autosomal dominant disease that is characterized by tumors on the vestibular branch of the VIII cranial nerve, but other types of nervous system tumors usually occur as well. Genotype-phenotype correlations are well documented for overall NF2 disease severity but have not been definitively evaluated for specific types of non-VIII nerve tumors. We evaluated genotype-phenotype correlations for various types of non-VIII nerve tumors in 406 patients from the population-based United Kingdom NF2 registry, using regression models with the additional covariates of current age and type of treatment center (specialty or nonspecialty). The models also permitted consideration of intrafamilial correlation. We found statistically significant genotype-phenotype correlations for intracranial meningiomas, spinal tumors, and peripheral nerve tumors. People with constitutional NF2 missense mutations, splice-site mutations, large deletions, or somatic mosaicism had significantly fewer tumors than did people with constitutional nonsense or frameshift NF2 mutations. In addition, there were significant intrafamilial correlations for intracranial meningiomas and spinal tumors, after adjustment for the type of constitutional NF2 mutation. The type of constitutional NF2 mutation is an important determinant of the number of NF2-associated intracranial meningiomas, spinal tumors, and peripheral nerve tumors.