Neurofibromatosis

Whole-exome sequencing revealed a likely pathogenic variant in NF1 causing neurofibromatosis type I and Arrhythmogenic Cardiomyopathy

BACKGROUND

Neurofibromatosis type I (NF1) is a genetic disorder characterized by the tumor's development in nerve tissue. Complications of NF1 can include pigmented lesions, skin neurofibromas, and heart problems such as cardiomyopathy. In this study, we performed whole-exome sequencing (WES) on an Iranian patient with NF1 to identify the genetic cause of the disease.

METHODS

Following clinical assessment, WES was used to identify genetic variants in a family with a son suffering from NF1. No symptomatic manifestations were observed in other family members. In the studied family, in silico and segregation analysis were applied to survey candidate variants.

RESULTS

Clinical manifestations were consistent with arrhythmogenic cardiomyopathy (ACM). WES detected a likely pathogenic heterozygous missense variant, c.3277G > A:p.Val1093Met, in the NF1 gene, confirmed by PCR and Sanger sequencing. The patient's parents and brother had a normal sequence at this locus.

CONCLUSIONS

Although there is no cure for NF1, genetic tests, such as WES, can detect at-risk asymptomatic family members. Furthermore, cardiac evaluation could also help these patients before heart disease development.

Solitary neurofibroma in the external auditory canal

Significance Statement: Neurofibromas, derived from perineural cells, are usually benign in the nervous system. Although neurofibromas are common in the head and neck, they rarely affect the external auditory canal (EAC), and few cases have been reported. We describe a case of a solitary EAC neurofibroma with otoscopy, radiological imaging, a surgical approach, and an uneventful outcome.

Neurofibromatosis Type Two: A Case With Both Intracranial and Spinal Lesions

We discuss the case of a 36-year-old male patient who presented with gait impairment. On examination, he had clinical findings of cervical myelopathy. The patient was evaluated with an MRI of the brain and spine, which revealed multiple spinal tumors, some causing significant canal stenosis. The spinal tumors involved the cervical, thoracic, and lumbar regions. There were both intramedullary and extramedullary tumors with an extraspinal extension. The patient's MRI brain also revealed bilateral vestibular schwannomas. His family history was negative. He subsequently underwent surgery for multiple spinal lesions followed by debulking of the right-sided vestibular schwannoma. The radiological findings of both intramedullary and extramedullary spinal tumors affecting the spinal cord and extensively involving the cervical, thoracic, and lumbar regions, and the requirement of spinal and cranial surgery concurrently make this a challenging neurosurgical case.

Targeted genetic and molecular therapies in neurofibromatosis - A review of present therapeutic options and a glimpse into the future

Neurofibromatosis type 1, the most common phakomatoses, can present with a host of signs and symptoms, usually involving the skin and the peripheral nervous system. It is characterized by a mutation in the neurofibromatosis type 1 gene on chromosome 17q11.2 that codes for the protein neurofibromin. Neurofibromin acts as a tumor suppressor gene by inhibiting rat sarcoma (Ras) activity and its deficiency leads to increased Ras activity, cellular proliferation and tumor formation. This review was conducted to analyze the various targeted therapies at the genetic and molecular level employed to manage the tumors and other clinical presentations associated with neurofibromatosis type 1. Twenty-eight studies of treatment modalities for the conditions associated with neurofibromatosis and which involved either targeted gene therapy or molecular level therapies, including the latest advances, were included in this review. Mitogen-activated protein kinase kinase inhibition, mammalian target of Rapamycin inhibition and Tyrosine kinase inhibition, represent some of the newer treatment options in this category. Although there are a number of trials for providing therapeutic options at the genetic and molecular level for the various physical and psychological morbidities associated with neurofibromatosis type 1, most of them are in the preclinical stage. Increased clinical trials of the molecules and gene therapies could significantly help in managing the various chronic and sometimes, life-threatening conditions associated with neurofibromatosis 1 and these will probably represent the preferred treatment direction of the future.

[Isolated neurofibroma of the tongue]

A clinical case of successful treatment of isolated tongue neurofibroma presented patient K., 64 years old, referred to the clinic complaining of a feeling of «discomfort» on swallowing. With a comprehensive examination, a diagnosis of an isolated tongue neurofibroma was established. Surgical treatment was performed. The diagnosis was confirmed morphologically. The presented clinical case of isolated tongue neurofibroma in an elderly patient is casuistic in nature, of scientific and practical interest due to the rarity and unusualness of the disease.

Solitary and complicated neurofibroma of small Bowel: A case report

INTRODUCTION

Neurofibromatosis is a genetic disorder characterized by tumors and pigmentary changes on the skin, such as spots that color leans to 'White Coffee'. Neurofibromas of the gastrointestinal tract are commonly associated with neurofibromatosis type I (NF1). Although, digestive involvement can be the single manifestation of the disease and may consequently; represent the only diagnostic element.

PRESENTATION OF CASE

We report here; a case of a patient admitted to the emergency department with a bowel obstruction, for which radiological investigations revealed the presence of intussusception due to an intestinal tumor. The patient underwent a bowel resection with anastomosis, and then, after being examined histologically, the result has identified an intestinal neurofibroma without evidence of malignancy. Then and on the fourth day following the surgery, the patient was discharged with good clinical improvement.

DISCUSSION

The intestinal neurofibroma may be the first and the only manifestation of neurofibromatosis type I. Also, it's uncommon to present a neurofibroma isolated from the small bowel with an intussusception, which makes the pre-surgical diagnosis very difficult. And until now, only a few case reports of these conditions have been reported.

CONCLUSION

We report this uncommon clinical case of an isolated neurofibroma from the small bowel to raise awareness among the medical team about this exceptional pathology. Nevertheless, its risk of developing serious complications and malignant transformation led us to opt for earlier surgical treatment. Furthermore, it requires a close clinical follow-up to eliminate the neurofibromatosis type I or the multiple endocrine neoplasia type II.

Pigmented Lesions

Oral pigmented lesions have a wide range of clinical presentations, some of which correlate with cutaneous pigmented lesions. This article highlights these correlates and underscores important differences that can potentially have clinical impact. Moreover, given a nonspecific presentation of an oral pigmented lesion, the article provides a reference to aid clinicians with differential diagnoses based on clinical features. This article is an overview of pigmented lesions of the oral cavity, including localized reactive pigmented lesions, neoplastic pigmented lesions, and pigmented lesions as sequelae of a systemic disease.

Structural Insights into the SPRED1-Neurofibromin-KRAS Complex and Disruption of SPRED1-Neurofibromin Interaction by Oncogenic EGFR

Sprouty-related, EVH1 domain-containing (SPRED) proteins negatively regulate RAS/mitogen-activated protein kinase (MAPK) signaling following growth factor stimulation. This inhibition of RAS is thought to occur primarily through SPRED1 binding and recruitment of neurofibromin, a RasGAP, to the plasma membrane. Here, we report the structure of neurofibromin (GTPase-activating protein [GAP]-related domain) complexed with SPRED1 (EVH1 domain) and KRAS. The structure provides insight into how the membrane targeting of neurofibromin by SPRED1 allows simultaneous interaction with activated KRAS. SPRED1 and NF1 loss-of-function mutations occur across multiple cancer types and developmental diseases. Analysis of the neurofibromin-SPRED1 interface provides a rationale for mutations observed in Legius syndrome and suggests why SPRED1 can bind to neurofibromin but no other RasGAPs. We show that oncogenic EGFR(L858R) signaling leads to the phosphorylation of SPRED1 on serine 105, disrupting the SPRED1-neurofibromin complex. The structural, biochemical, and biological results provide new mechanistic insights about how SPRED1 interacts with neurofibromin and regulates active KRAS levels in normal and pathologic conditions.

An Aggressive Extension of Dumbbell-Type Pediatric Skull Base Meningioma: A Case Report with Review of the Literature

BACKGROUND

Pediatric meningiomas account for less than 2% of pediatric brain tumors. Pediatric clear cell meningiomas (CCMs) occurring in the posterior fossa are particularly rare. Therapeutic strategies differ among the previous pediatric CCM case reports. Therefore, to clarify the clinical features of pediatric CCMs, we report a rare case of dumbbell-type pediatric CCM and a corresponding literature review.

CASE DESCRIPTION

A 7-year-old boy with complaints of headache, left facial palsy, dysarthria, and left-sided ataxic gait was emergently admitted to our hospital. His consciousness level was slight stupor, with Glasgow Coma Scale score 3-5-6, and he showed left ptosis, dysarthria, and ataxias of the left trunk and extremities. Magnetic resonance imaging (MRI) scan showed acute obstructive hydrocephalus because of the tumor's compression of the brainstem. The dumbbell-shaped tumor extended from the lateral wall of the cavernous sinus, through the left Meckel's cave, to the cerebellopontine angle. Physical examination and perioperative MRI scan showed no evidence regarding neurofibromatosis type I or II. The tumor was removed in a 2-staged operation. Postoperative proton therapy was done to treat some residual tumors. One year after postoperative proton therapy, there is no recurrence, and apart from left corneal and facial hypesthesia, he is healthy.

CONCLUSIONS

We reported a rare case of pediatric skull base-type CCM with huge extension originating from the anteromedial wall of Meckel's cave firmly adhered to the cavernous sinus wall to the posterior fossa that was successfully treated with surgery and postoperative proton therapy. CCM has a high recurrence rate; therefore, careful prolonged follow-up is needed.

Spontaneous bilateral hemothorax in neurofibromatosis type 1 due to internal thoracic artery aneurysm: Case report

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In patients with NF1, the risk of spontaneous bleeding due to the possibility of aneurysmal formation should be considered.

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The differential diagnosis of neurofibromatosis should be investigated in cases of spontaneous hemothorax.

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In most cases of spontaneous hemothorax associated with NF1, intercostal artery aneurysm is the most common injury.

Introduction

Vascular lesions are associated with neurofibromatosis 1, including stenosis and aneurysms.

Presentation of a case

A 43-year-old man presented with sudden respiratory failure in our emergency medical service. Physical examination suggested diagnosis of neurofibromatosis. Chest computed tomography revealed a sizeable bilateral hemothorax. He was then submitted to arteriography, which evidenced the right internal thoracic artery aneurysm. The aneurysm was selectively catheterized and embolized, followed by a video-assisted thoracoscopy surgery to drain the hemothorax.

Discussion

The bleeding dissected to both pleural cavities, causing the bilateral hemothorax. Although the patient did not have a medical diagnosis of neurofibromatosis before the occurrence, the presence of clinical signs of the disease, associated with the exclusion of other causes for hemothorax, allowed differential diagnosis and appropriate treatment.

Conclusion

The differential diagnosis of neurofibromatosis should be advanced in cases of spontaneous bleeding. In patients diagnosed with neurofibromatosis, the risk of spontaneous bleeding due to the possibility of aneurysmal formation should be considered.

Genetic and developmental disorders of the oral mucosa: Epidemiology; molecular mechanisms; diagnostic criteria; management

A large number of disorders may affect the oral cavity, including genetic diseases, infections, cancers, blood diseases, skin diseases, endocrine and metabolic disorders, autoimmune and rheumatologic diseases, local lesions, to name a few. Oral mucosa shows a considerable variation in its normal structure and a wide range of conditions may affect it. Such conditions are often harmless or minor and could be primary or secondary to systemic disease. Several of them are quite rare and, hence, the diagnosis is not easy. Clinically, lesions may appear as ulcers, discoloration of the oral mucosa and alterations in size and configuration of oral anatomy. Genetic disorders have specific manifestations and can be caused by a derangement of one or more components of the tissue. Many of them follow the skin or systemic signs of the underlying genetic disease, but in a few cases oral signs could be the first manifestation of the disorder. Among them genodermatoses are prominent. They are inherited disorders characterized by a multisystem involvement. This review describes chondro-ectodermal dysplasia, dyskeratosis congenita, Ehlers-Danlos syndrome, hereditary benign intraepithelial dyskeratosis, keratosis follicularis, lipoid proteinosis, multiple hamartoma syndrome, pachyonychia congenita, Peutz-Jeghers syndrome, tuberous sclerosis and white sponge nevus. Other genetic disorders not included in the genodermatosis group and reported in the present review are: acanthosis nigricans, angio-osteo-hypertrophic syndrome, encephalotrigeminal angiomatosis, familial adenomatous polyposis, focal dermal hypoplasia, focal palmoplantar and oral mucosa hyperkeratosis syndrome, gingival fibromatosis, Maffucci's syndrome, neurofibromatosis (type 1) and oro-facial-digital syndrome (type 1). Disorders during embryonic development might lead to a wide range of abnormalities in the oral cavity; some of them are quite common but of negligible concern, whereas others are rare but serious, affecting not only the oral mucosa, but also other structures of the oral cavity (ie palate, tongue and gingiva). Fordyce's granules, leukoedema, cysts of the oral mucosa in newborns, retrocuspid papilla, geographic tongue, fissured tongue, median rhomboid glossitis, hairy tongue, lingual varices and lingual thyroid nodule are described. This review may help dentists, dental hygienists, but also general internists and pediatricians to diagnose different disorders of the oral mucosa, to understand the pathogenesis and to schedule a treatment plan.

"Transforming the Beast to A Beauty"- Fifteen Years into the Making - Case Report of Congenital Neurofibromatosis

BACKGROUND:

In 1882, the German pathologist Friedrich Daniel von Recklinghausen described a series of patients with a combination of cutaneous lesions and tumours of the peripheral and central nervous system. Succeeding this paper, all of the patients with similar symptoms were given the diagnosis “von Recklinghausen disease”. In the 20th century, a distinction was made between Neurofibromatosis type 1 (NF1) and Neurofibromatosis type 2 (NF2) with the help of molecular testing.

CASE REPORT:

We are presenting the results from multiple surgical esthetic and reconstructive surgical procedures performed on a female patient with severe congenital neurofibromatosis during 15 years (2000-2015). The external appearance of our patient was not reflected in the general public’s beauty standards. Convinced that she was unusual and unaccepted by the society, she gathered all of the strength and became our patient at 15 years of age.

CONCLUSION:

Transforming the patient’s life in the next fifteen years improved her overall health and her life quality.

Rotatory Dislocation of the Spine in Dystrophic Kyphoscoliosis Secondary to Neurofibromatosis Type 1

Aim of the study

Neurofibromatosis type 1 (NF-1) is associated with the development of scoliosis or kyphoscoliosis. The deformity is rapidly progressive in the presence of dystrophic changes producing bone erosion. Vertebral subluxation or dislocation can occur in children with highly dystrophic kyphoscoliosis and carries an increased risk of paralysis. There is no standardised treatment for this extreme deformity with very few patients currently reported in the literature.

Methods

Retrospective review of a patient with NF-1 who developed a dystrophic upper thoracic kyphoscoliosis with segmental displacement of T2 on T3.

Results

We report a patient with NF-1 who presented at 8.9 years with a progressive upper thoracic kyphoscoliosis. At 18.8 years, the deformity had deteriorated to scoliosis 65° and kyphosis 78° with fixed segmental rotatory dislocation at T2-T3. He underwent posterior cervico-thoracic fusion with concave pedicle screw/hook/rod instrumentation and iliac crest bone. Minimum correction was achieved due to curve rigidity and inability to reduce the T2/T3 displacement by halo-femoral traction. At 7 months, an elective posterior re-grafting procedure was performed followed by anterior fusion with rib strut grafts between T2-T6 through a midline sternotomy. The patient is now 3.5 years after anterior surgery and remains neurologically intact with stable residual deformity and computed tomographic evidence of circumferential fusion. He has no back pain and resumed non-contact physical activities.

Conclusions

Patients with NF-1 can develop dystrophic kyphoscoliosis with segmental spinal subluxation/dislocation. Circumferential fusion is a technically challenging procedure which often requires a multi-disciplinary surgical team but produces satisfactory clinical outcome preventing paraplegia.

Spectrum of gastrointestinal lesions of neurofibromatosis type 1: a pictorial review

Abstract

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders. Gastrointestinal manifestations of NF-1 are seldom thought of in routine clinical practice and might thus be significantly under-recognised. Their heterogeneous spectrum ranges from localised microscopic proliferative lesions to grossly recognizable mass-forming neurofibromas, neuroendocrine and gastrointestinal stromal tumours (GIST). The aim of this study is discussing the imaging evaluation and characterisation of the abdomen lesions in patients with NF1.

Teaching Points

• Neurofibromatosis type (NF-1) is one of the most common single gene disorders.

• Every organ system can be involved and intra-abdominal manifestations are underestimated.

• The NF1 abdominal manifestations comprehend five categories of tumours.

• Neurogenic tumours including with neurofibromas are the most common type.

• Early diagnosis of abdominal manifestations of NF-1 based on imaging patterns is necessary for appropriate treatment to avoid serious organic complications related to tumour mass.

Perioperative Care of the Patient With Acoustic Neuroma

Acoustic neuromas, also known as vestibular schwannomas, are slow-growing, benign tumors that develop on the eighth cranial nerve. Common signs and symptoms of an acoustic neuroma include hearing loss and balance disturbances. A physical examination, a hearing evaluation, and diagnostic imaging assist in the diagnosis of an acoustic neuroma. Patients with a confirmed tumor have three treatment options: observation, stereotactic radiosurgery, and surgical removal. Complications include cerebrospinal fluid leakage, damage to ancillary brain structures, facial nerve damage, and bleeding or vascular injury. This article focuses on the surgical removal of an acoustic neuroma and the role of the perioperative nurse in the perioperative care of the patient.

Use of Surgical Laser for Excision of a Neurofibroma Associated With Neurofibromatosis Type-1

Introduction: Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder that affects approximately 1/3500 individuals. Various bone manifestations and peripheral nerves neoplastic lesions associated with NF1 are seen in the jaws. Several oral manifestations may occur in this disorder; therefore the dentist's knowledge and multidisciplinary management of these patients are extremely important. Case Presentation: In the present article, we present the use of a high-power surgical laser to excise a neurofibroma in a patient with several intraoral manifestations associated with NF1. Conclusion: The use of diode laser (808 nm) for excision biopsy of tongue nodules showed no thermal damage to the tissue, allowing an adequate histopathological analysis of the neurofibroma.

Not so mass effect? Finding of a remarkable 'incidentaloma' in a teenager with neurofibromatosis

A 13-year-old boy with neurofibromatosis type 1 presented to the emergency department twice in a fortnight with moderate intermittent abdominal pain, radiating to the back and associated with nausea and vomiting. He examined as a well child with a soft abdomen and minimal tenderness. A history of constipation was identified but he failed to respond to a trial of laxatives. Subsequent ultrasound abdomen demonstrated a large mass surrounding the porta hepatis. MRI further characterised a focal, non-aggressive lesion extending from his liver, encapsulating his pancreas, portal vessels and laterally displacing his spleen and left kidney. Biopsy performed at a specialist cancer treatment hospital of our reference later confirmed this to be a benign neurofibroma of a size not previously reported in the literature. He will be managed conservatively with surveillance imaging and the potential for chemotherapy should the lesion continue to grow.

Large penile plexiform neurofibroma in an 11-year old boy

Background

Neurofibromatosis is a genetically inherited disorder of the nervous system (brain and spinal cord) which mainly affects the development of nerve (neural) cell tissues, causing tumors (neurofibromas) to develop on nerves. It is the most common single gene disorder of the nervous system and inheritance is through autosomal dominance. They are usually classified into types 1 and 2, the type 1 is the commoner type and also known as superficial neurofibroma. Plexiform neurofibromas are the next most common type of tumor in individuals with type 1 neurofibroma. Plexiform neurofibromas are histologically benign tumors that are made up of a variety of cell types including neuronal axons, Schwann cells, fibroblasts, mast cells, macrophages, perineural cells and extracellular matrix materials such as collagen. They can occur in any part of the body and can grow throughout the person's lifetime, often becoming disfiguring, disabling or deadly via compression of vital structures or conversion to a malignant sarcoma or malignant peripheral nerve sheath turmor. The aim of this report is to present a large penile plexiform neurofibroma which required extensive dissection for complete excision and reconstruction of the phallus and glans penis.

Objectives

To present a huge penile plexiform neurofibroma and the mode of surgical treatment.

Methods

The huge penile plexiform neurofibroma was completely excised and the penile defect resulting from the excision was repaired.

Conclusion

Plexiform neurofibromas are congenital tumors of peripheral nerve sheaths which may also develop near nerve roots deep within the body. They are usually benign but carry a malignant potential in 5-10% of patients. Plexiform neurofibromas are commoner in the face, chest and limbs but the index case occurred on the penile shaft.

Altered cerebrospinal fluid dynamics in neurofibromatosis type l: severe arachnoid thickening in patients with neurofibromatosis type 1 may cause abnormal CSF dynamic

INTRODUCTION

The object of this study is to understand abnormal dynamic of cerebrospinal fluid (CSF) in patients with neurofibromatosis type 1 (NF1), which may cause temporal lobe herniation and bulging of temporal fossa.

METHODS

Four patients, three females and one male, with NF1 were studied retrospectively. They presented with a similar craniofacial deformity, which consisted of pulsatile exophthalmos, an enlarged bony orbit, dysplasia of the sphenoid wing with the presence of a herniation of the temporal lobe into the orbit, and a bulging temporal fossa.

RESULTS AND DISCUSSION

Surgical exploration demonstrated abnormally thickened arachnoid membrane in one case. Protruding temporal lobe, which was one of the main symptoms in NF1 patients, could be stopped by control of intracranial pressure (ICP) via programmable ventriculoperitoneal shunt (VPS) or extra ventricle drainage implantation. The dense fibrosis of the arachnoid membrane and consequent altered hemispheric CSF dynamics may cause symptoms including pulsatile exophthalmos and consequent worsening of vision, prolapse of the temporal lobe, and enlargement of the temporal fossa. This finding may not present with general features of hydrocephalus, so that delays in diagnosis often result.

CONCLUSION

For the NF1 patients with cranio-orbito-temporal deformities, prior to any surgical reconstruction, control of increased ICP (IICP) should be primarily considered.

mTOR inhibitors in the pharmacologic management of tuberous sclerosis complex and their potential role in other rare neurodevelopmental disorders

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder that affects multiple organ systems throughout the body. Dysregulation of the mammalian target of rapamycin (mTOR) pathway is implicated in the disease pathology, and evidence exists to support the use of mTOR inhibitors in treatment. The mTOR pathway has also been investigated as a potential treatment target for several other rare diseases. TSC research has highlighted the value of pursuing targeted therapies based on underlying molecular pathophysiology. One goal of current research is to identify the role of mTOR inhibition in neurologic and developmental disorders apart from TSC. There is also particular interest in the potential role of mTOR inhibitors in preventing seizures, neurodevelopmental disabilities, renal tumors, cutaneous tumors, and other manifestations typically seen in TSC. It is foreseeable that use of mTOR inhibition to prevent long-term morbidity in TSC will become mainstream therapeutic practice. This review will provide an overview of the relationship between the mTOR pathway and TSC disease pathology, summarize the clinical evidence supporting the use of mTOR inhibitors for treatment of the various manifestations of TSC, and discuss the potential therapeutic role of mTOR inhibitors in several rare diseases.

Association Between Juvenile Myelomonocytic Leukemia, Juvenile Xanthogranulomas and Neurofibromatosis Type 1: Case Report and Review of the Literature

The occurrence of juvenile myelomonocytic leukemia (JMML), juvenile xanthogranuloma (JXG), and neurofibromatosis type 1 (NF1) together is relatively rare. Approximately only 20 cases have been reported in the literature. It is debated whether children with NF1 and JXG are at higher risk of developing JMML than children with NF1 alone. We present the case of a boy primarily diagnosed with NF1 with coexisting JXG who developed JMML at the age of 22 months. The clinical course from initial presentation to final diagnosis is detailed and the genetic features and hematologic characteristics are discussed. We report this case to underscore the importance of close monitoring of blood count and strict clinical follow-up in children presenting with concurrent NF1 and JXG and provide a possible explanation for this association.

Successful cochlear implantation in two profoundly deafened patients with neurofibromatosis type 1: further evidence to support a cochlear site of lesion

OBJECTIVE

To investigate the usefulness of cochlear implantation and to examine the evidence for a cochlear or retrocochlear site of lesion for deafness in Neurofibromatosis Type 1 (NF1).

PATIENTS

Two profoundly deafened NF1 patients who underwent cochlear implantation.

INTERVENTIONS

Preoperative electrophysiologic and audiologic evaluation including pure-tone audiometry, auditory brainstem response, speech audiometry, otoacoustic emission, and promontory stimulation test. Intraoperative electrophysiologic tests were also performed.

MAIN OUTCOME MEASURES

Results of preoperative diagnostic workup. Cochlear implant performances were evaluated in the auditory-only condition in both closed-set and open-set formats.

RESULTS

Preoperative diagnostic assessment suggested cochlear impairment with preserved auditory pathway at the basis of the sensorineural hearing loss in both patients. Intraoperative electrically evoked auditory nerve and brainstem responses confirmed the integrity of the neural population all along the length of the cochlea. To date, with a follow-up of 2 and 10 years, both patients gained excellent open-set, auditory-only, speech understanding and were able to converse on the telephone without a code.

CONCLUSION

Cochlear impairment with preserved auditory pathways can be responsible for sensorineural hearing loss in NF1 patients. When their hearing deficit meets criteria for cochlear implantation, this type of auditory rehabilitation can restore social hearing in these patients while dramatically improving their quality of life.

FRAX597, a small molecule inhibitor of the p21-activated kinases, inhibits tumorigenesis of neurofibromatosis type 2 (NF2)-associated Schwannomas

The p21-activated kinases (PAKs) are immediate downstream effectors of the Rac/Cdc42 small G-proteins and implicated in promoting tumorigenesis in various types of cancer including breast and lung carcinomas. Recent studies have established a requirement for the PAKs in the pathogenesis of Neurofibromatosis type 2 (NF2), a dominantly inherited cancer disorder caused by mutations at the NF2 gene locus. Merlin, the protein product of the NF2 gene, has been shown to negatively regulate signaling through the PAKs and the tumor suppressive functions of Merlin are mediated, at least in part, through inhibition of the PAKs. Knockdown of PAK1 and PAK2 expression, through RNAi-based approaches, impairs the proliferation of NF2-null schwannoma cells in culture and inhibits their ability to form tumors in vivo. These data implicate the PAKs as potential therapeutic targets. High-throughput screening of a library of small molecules combined with a structure-activity relationship approach resulted in the identification of FRAX597, a small-molecule pyridopyrimidinone, as a potent inhibitor of the group I PAKs. Crystallographic characterization of the FRAX597/PAK1 complex identifies a phenyl ring that traverses the gatekeeper residue and positions the thiazole in the back cavity of the ATP binding site, a site rarely targeted by kinase inhibitors. FRAX597 inhibits the proliferation of NF2-deficient schwannoma cells in culture and displayed potent anti-tumor activity in vivo, impairing schwannoma development in an orthotopic model of NF2. These studies identify a novel class of orally available ATP-competitive Group I PAK inhibitors with significant potential for the treatment of NF2 and other cancers.

The riddle of multinucleated "floret-like" giant cells and their detection in an extensive gluteal neurofibroma: a case report

Introduction

The neurofibromatoses are inherited tumor predisposition syndromes involving two major clinical phenotypes: neurofibromatosis type 1 (von Recklinghausen's disease) is linked to chromosome 17q, and tends to occur seven times more frequently than neurofibromatosis type 2. Neurofibromatosis type 1 entails a distinctive cutaneous manifestation prevailed upon by benign neurofibromas, which may vary in size, number and distribution. On the histological level, neurofibromas are composed of an admixture of neurilemmal cells, including Schwann cells, fibroblasts, and – to a lesser extent – perineurial cells.

Case presentation

The case of a 39-year-old Caucasian man with a voluminous recurrent neurofibroma of 27×15cm extending from the left gluteal region to thoraco-lumbar levels Th6 through L4 is reported. Within the soft tissue tumor a pseudocyst of 7.3×9.3cm was found preoperatively.

Conclusion

Histopathological study of the excised mass was conspicuous for revealing a large number of multinucleated floret-like giant cells within an otherwise classical soft tissue neurofibroma.

Previous reports on neurofibromas with multinucleated floret-like giant cells are distinctly scant. Available evidence from the literature does not suggest any consistent correlation of multinucleated floret-like giant cells in neurofibromas with gender, age, traumatic antecedents, size of the lesion, recurrence, or malignant transformation. Furthermore, the presence of such cells may not be specific for neurofibromatosis type 1, as they occasionally are encountered in some unrelated mesenchymal neoplasms as well.

Sciatic nerve tumor and tumor-like lesions - uncommon pathologies

Sciatic nerve mass-like enlargement caused by peripheral nerve sheath tumors or neurocutaneous syndromes such as neurofibromatosis or schwannomatosis has been widely reported. Other causes of enlargement, such as from perineuroma, fibromatosis, neurolymphoma, amyloidosis, endometriosis, intraneural ganglion cyst, Charcot-Marie-Tooth disease, and chronic inflammatory demyelinating polyneuropathy are relatively rare. High-resolution magnetic resonance imaging (MRI) is an excellent non-invasive tool for the evaluation of such lesions. In this article, the authors discuss normal anatomy of the sciatic nerve and MRI findings of the above-mentioned lesions.

Peripheral and cranial nerve sheath tumors-a clinical spectrum

To analyze the incidence of nerve sheath tumors in a tertiary care hospital over a period of 5 years and review the literature. Medical case records from last 5 years were retrieved and histopathology and operative details were studied in a retrospective analysis. There is a slight male preponderance when it comes to nerve sheath tumors and acoustic schwannomas accounted for the largest fraction among schwannomas. Nerve sheath tumors include a wide spectrum of schwannomas, neurofibromas and malignant peripheral nerve sheath tumors. Hence combination of clinical, pathological and surgical expertise is needed to diagnose accurately.

Comparison of the background, needs, and expectations for genetic counseling of adults with experience with Down syndrome, Marfan syndrome, and neurofibromatosis

We describe an analysis of the responses of 605 adults with experience with Down syndrome, Marfan syndrome, or neurofibromatosis (NF) to the BNE Scale, a scale specifically designed to assess the background, needs, and expectations (BNE) of genetic counseling patients. Significant group differences were found. Specifically, the respondents in the Down syndrome group reported more favorable beliefs about the condition and the availability of social support than the respondents in the other groups. Respondents in the NF group reported more unsureness about their condition and a greater need for genetic information than members of the other groups. Notably, having positive feelings about the condition was negatively correlated with support group interest for respondents of the Marfan syndrome group (r = -0.159, P < 0.01). Having an affected child was associated with interest in health provider input (t = -3.4; P = 0.001) and the desire to talk about psychosocial issues (t = -2.9; P = 0.004). However, previous experience with genetic counseling was not found to affect BNE. These results support the usefulness of the BNE Scale to compare the BNE of patient groups, as well as provide important insight into the BNE of individuals seeking counseling about Down syndrome, Marfan syndrome, and NF.

Solitary plexiform neurofibroma, a pitfall in diagnosis of lipoma

Plexiform neurofibromatosis is almost invariably associated with neurofibromatosis type I. A case of an isolated back plexiform neurofibroma, initially thought to be a lipoma, is presented, with emphasis on the importance of eliciting family history in reaching a diagnosis of neurofibromatosis. Currently, surgical resection is still the treatment of choice though a management plan is not well defined. Patients need appropriate regular follow-up to detect malignancy or early recurrence.

A Rare Case of Radiologically Not Distinguishable Coexistent Meningioma and Vestibular Schwannoma in the Cerebellopontine Angle - Case Report and Literature Review

Background

The simultaneous occurrence of cerebellopontine angle (CPA) meningioma and vestibular schwannoma (VS) in the absence of neurofibromatosis type 2 or history of irradiation is very rare. We report a case with coexistent CPA meningioma and VS, which were radiologically not distinguishable in preoperative imaging.

Case Description

A 46-year-old female presented with acute hearing loss, tinnitus and gait ataxia. Otorhinolaryngological diagnostic workup and imaging studies showed an intra- and extrameatal homogenous contrast enhancing lesion. The neuroradiological diagnosis was VS. The patient was operated via the retrosigmoid approach.

Intraoperatively two distinct tumors were found: a small, mainly intrameatally located VS and a larger meningioma originating from the dura of the petrous bone. Both tumors were completely microsurgically removed. The patient experienced no new neurological deficit after surgery; particularly facial nerve function was completely preserved. Histopathological examination revealed a fibromatous meningioma and a VS, respectively.

Conclusions

The coincidental occurrence of CPA meningioma and VS is very rare. Careful interpretation of imaging studies before surgery is crucial. Even such rare cases should be kept in mind when discussing the therapeutic options with the patient. More studies are needed for a better understanding of mechanisms leading to multiple tumor growth.

Development of small-molecule inhibitors of the group I p21-activated kinases, emerging therapeutic targets in cancer

The p21-activated kinases (PAKs), immediate downstream effectors of the small G-proteins of the Rac/cdc42 family, are critical mediators of signaling pathways regulating cellular behaviors and as such, have been implicated in pathological conditions including cancer. Recent studies have validated the requirement for PAKs in promoting tumorigenesis in breast carcinoma and neurofibromatosis. Thus, there has been considerable interest in the development of inhibitors to the PAKs, as biological markers and leads for the development of therapeutics. While initial approaches were based on screening for competitive organic inhibitors, more recent efforts have focused on the identification of allosteric inhibitors, organometallic ATP-competitive inhibitors and the use of PAK1/inhibitor crystal structures for inhibitor optimization. This has led to the identification of highly selective and potent inhibitors, which will serve as a basis for further development of inhibitors for therapeutic applications.

A 38-year review of oral schwannomas and neurofibromas in a Brazilian population: clinical, histopathological and immunohistochemical study

The benign peripheral nerve sheath tumours are rare lesions mainly represented by schwannoma and neurofibroma. The present work evaluated the clinical and histopathological features of schwannomas and neurofibromas of the oral cavity diagnosed in a Brazilian population. Among 9.000 cases of oral lesions archived from 1970 to 2008, four schwannomas and 12 neurofibromas were identified, microscopically revised and immunohistochemically certified through a panel including monoclonal antibodies (anti-S100, vimentin, HHF-35 and desmin). From biopsy and histological sections records, clinical and histopathological data were retrieved, reviewed and statistically analysed. Predominantly, schwannomas affected non-white males (3:1), with an age and size averages of 34.7 years and 2.8 cm, respectively. Neurofibromas preferentially occurred on the gingival/alveolar ridge of white females (5:1), with 35.7-year mean age, peak of incidence between 3rd and 5th decade, and size average of 1.7 cm. (12 cases, 75%). The studied tumours exhibited more frequently as a painless, sessile and slow growth very similar to other oral lesions, but their microscopic features differed significantly. Schwannomas and neurofibromas are extremely uncommon in the oral cavity, exhibiting clinical features very similar but specific and peculiar microscopic findings that are useful in the establishment of the diagnosis, which in some particular cases must be confirmed by immunohistochemistry.

Juvenile xanthogranuloma in a child with previously unsuspected neurofibromatosis type 1 and juvenile myelomonocytic leukemia

The association of neurofibromatosis 1 (NF1), juvenile xanthogranulomas (JXG), and juvenile myelomonocytic leukemia (JMML) has been previously reported. We describe herein this triad in a Caucasian male infant with a pathogenic mutation in the NF1 gene (neurofibromin). The clinical course from initial presentation to final diagnosis is detailed; the physical features and hematologic characteristics are discussed. The patient underwent bone marrow transplantation and is currently in remission. Children with concurrent cutaneous café-au-lait and JXG lesions should be evaluated and monitored closely for the possible development of JMML.

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.