Intracranial neoplasms in children with neurofibromatosis 1

Molecular Characterization of Medulloblastoma in a Patient with Neurofibromatosis Type 1: Case Report and Literature Review

Brain tumors are the most common solid neoplasms of childhood. They are frequently reported in children with Neurofibromatosis type 1 (NF1). The most frequent central nervous system malignancies described in NF1 are optic pathway gliomas and brainstem gliomas. Medulloblastoma (MB) in NF1 patients is extremely rare, and to our knowledge, only 10 cases without molecular characterization are described in the literature to date. We report the case of a 14-year-old girl with NF1 that came to our attention for an incidental finding of a lesion arising from cerebellar vermis. The mass was completely resected, revealing a localized classic medulloblastoma (MB), subgroup 4. She was treated as a standard-risk MB with a dose-adapted personalized protocol. The treatment proved to be effective, with minor toxicity. Brain and spine MRI one year after diagnosis confirmed the complete remission of the disease. To our knowledge, this is the only case of MB reported in a patient with NF1 with molecular characterization by the methylation profile. The association between NF1 and MB, although uncommon, may not be an accidental occurrence.

MRI-based diagnosis and treatment of pediatric brain tumors: is tissue sample always needed?

Traditional management of newly diagnosed pediatric brain tumors (PBTs) consists of cranial imaging, typically magnetic resonance imaging (MRI), and is frequently followed by tissue diagnosis, through either surgical biopsy or tumor resection. Therapy regimes are typically dependent on histological diagnosis. To date, many treatment regimens are based on molecular biology. The scope of this article is to discuss the role of diagnosis and further treatment of PBTs based solely on MRI features, in light of the latest treatment protocols. Typical MRI findings and indications for surgical biopsy of these lesions are described.

New treatment modalities in NF-related neuroglial tumors

The management of low-grade gliomas (LGGs) and other neuroglial tumors in children with neurofibromatosis type 1 (NF1) has not changed over the past 2-3 decades. With the widespread utilization of chemotherapy for younger children with progressive LGGs, outcomes have been good for most patients who have required treatment. However, some may progress after the initiation of chemotherapy and others, although radiographically responding or with stable disease, may develop progressive neurologic and visual deterioration. Molecular-targeted therapy has become an option for patients who have progressed after receiving chemotherapy and the mTOR inhibitors and bevacizumab have already shown some degree of efficacy. However, the greatest impact has been the introduction of the MEK inhibitors. A variety of different MEK inhibitors are in clinical trials and have already demonstrated the ability to result in radiographic tumor shrinkage in the majority of children with NF1 and progressive LGGs. Because of this efficacy, the MEK inhibitors have moved rapidly from phase I studies to ongoing phase III studies comparing their benefit directly to that of chemotherapy. The long-term ability of these agents to not only control disease, but improve visual and/or neurological function, as well as their short- and long-term safety, are open questions that can only be answered by well-constructed prospective, often randomized, clinical trials.

Nonoptic pathway tumors in children with neurofibromatosis type 1

OBJECTIVE

To define the radiologic features and natural history of nonoptic pathway tumors (non-OPTs) in children with neurofibromatosis type 1 (NF1).

METHODS

We performed a retrospective cross-sectional analysis of 64 children with NF1 harboring 100 probable non-OPTs. Age at diagnosis, sex, tumor location, number of tumors, symptomology, concurrent OPT, radiographic progression (defined as qualitative and quantitative increases in size), and treatment were assessed. Tumor volumes were measured from initial presentation until treatment or end of disease progression.

RESULTS

Sixty-three percent of probable non-OPTs progressed over time, where radiographic progression was concomitantly associated with clinical progression. Fifty-two percent of patients had incidentally identified probable non-OPTs. Twenty-five percent of patients were symptomatic at initial diagnosis, all of whom harbored tumors that grew on subsequent scans and required tumor-directed therapy. There were no clinical differences between probable non-OPTs localized to the brainstem vs other locations with respect to age, sex, concurrent optic pathway glioma, symptomology, and treatment. The average time from diagnosis to stabilization or decrease in tumor size was 2.34 years (SD, 2.15 years). Nineteen biopsied lesions were all histopathologically confirmed as tumor. Six children (9%) had deep extensive tumors, who presented earlier (mean age at diagnosis, 3.88 years), required multiple treatments, and had a shorter mean progression-free survival (48 months).

CONCLUSIONS

Over half of children with NF1 in this study developed probable non-OPTs, the majority of which were clinically and radiographically progressive. While brainstem and nonbrainstem gliomas share similar clinical features and natural history, deep extensive tumors comprise a distinct aggressive group of tumors that warrant close attention.

Role of visual evoked potentials and optical coherence tomography in the screening for optic pathway gliomas in patients with neurofibromatosis type I

PURPOSE

The purpose of the present study was to compare visual function assessment, visual evoked potential, and optical coherence tomography with measurement of retinal nerve fiber layer thickness for the diagnosis of optic pathway glioma in children with neurofibromatosis type 1.

METHODS

This retrospective observational study included patients with neurofibromatosis type 1 who underwent brain magnetic resonance imaging scan, visual evoked potential study, and peripapillary retinal nerve fiber layer evaluation by optical coherence tomography. Patients were tested with pattern-reversal visual evoked potential and with flash visual evoked potential in case of poor cooperation. Optical coherence tomography was performed with HRA Spectralis (Heidelberg Engineering, Heidelberg, Germany). The area under the curve of receiver operating characteristic curves was used to evaluate the accuracy of each parameter for diagnosing optic pathway glioma.

RESULTS

In all, 110 patients with neurofibromatosis type 1 were included in the study. Fifty of them had an optic pathway glioma diagnosed with magnetic resonance imaging, while 60 did not. Global retinal nerve fiber layer thickness demonstrated the highest diagnostic power for discriminating patients with and without optic pathway glioma (area under the curve = 0.758, sensitivity = 65.3%, specificity = 83.3%), followed visual acuity (area under the curve = 0.723, sensitivity = 51.1%, specificity = 91.7%) and P100 of visual evoked potential (area under the curve = 0.712, sensitivity = 69.6%, specificity = 63.8%).

CONCLUSION

The results of the present study showed that the measurement of retinal nerve fiber layer thickness was the most efficient test for discriminating patients with and without optic pathway glioma. Brain magnetic resonance imaging remains the gold standard to confirm the diagnosis of optic pathway glioma. Longitudinal studies are required to define if the early detection of tumors with optical coherence tomography could prevent vision loss and morbidity.

Pediatric High Grade Gliomas in the Context of Cancer Predisposition Syndromes

Germline mutations in cancer causing genes result in high risk of developing cancer throughout life. These cancer predisposition syndromes (CPS) are especially prevalent in childhood brain tumors and impact both the patient’s and other family members’ survival. Knowledge of specific CPS may alter the management of the cancer, offer novel targeted therapies which may improve survival for these patients, and enables early detection of other malignancies. This review focuses on the role of CPS in pediatric high grade gliomas (PHGG), the deadliest group of childhood brain tumors. Genetic aspects and clinical features are depicted, allowing clinicians to identify and diagnose these syndromes. Challenges in the management of PHGG in the context of each CPS and the promise of innovative options of treatment and surveillance guidelines are discussed with the hope of improving outcome for individuals with these devastating syndromes.

Mobility Functional Outcomes of Neurofibromatosis Patients: A Preliminary Report

OBJECTIVE

The aim of the study was to describe the mobility outcomes of neurofibromatosis (NF) patients who received acute inpatient rehabilitation.

DESIGN

This is a retrospective study of 62 consecutive neurofibromatosis patients of any age who received physical medicine and rehabilitation consultations at a comprehensive cancer center. Postoperative, inpatient rehabilitation admission and discharge functional independence measures (FIM scores) of transfers and gait and length of hospital stay were obtained from 37 patients who were transferred to inpatient rehabilitation (acute rehabilitation) and 25 who had an alternative disposition (consultation only).

RESULTS

Mean age was 34 yrs. Both groups had similar postoperative FIM transfer and gait scores; however, at approximately postoperative day 10, the consultation only group was discharged with median FIM of 5 (supervision level) as compared with the acute rehabilitation group FIM of 4 (P = 0.000). The acute rehabilitation group had improved mobility FIM scores from postoperative to rehabilitation admission and again from rehabilitation admission to discharge (P < 0.0001). At discharge, the acute rehabilitation group ambulated a significantly longer distance (500 f. vs. 300 ft) (P = 0.04). The median length of hospital stay for the acute rehabilitation and consultation only groups was 20 and 10 days, respectively (P = 0.004).

CONCLUSIONS

Acute inpatient rehabilitation leads to improvement in mobility-associated FIM scores for neurofibromatosis patients minimizing caregiver needs at home.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

A multi-institutional study of brainstem gliomas in children with neurofibromatosis type 1

OBJECTIVE

To define the clinical and radiologic features of brainstem gliomas (BSGs) in children with neurofibromatosis type 1 (NF1).

METHODS

We performed a retrospective cross-sectional study of 133 children with NF1 and concurrent BSGs cared for at 4 NF1 referral centers. BSG was determined using radiographic criteria. Age at diagnosis, tumor location and appearance, clinical symptoms, treatment, and presence of a concurrent optic pathway glioma were assessed.

RESULTS

The average age at BSG diagnosis was 7.2 years, and tumors occurred most often in the midbrain and medulla (66%). The majority of children with NF1-BSGs were asymptomatic (54%) and were not treated (88%). Only 9 of the 72 asymptomatic children received treatment because of progressive tumor enlargement. In contrast, 61 children presented with clinical signs/symptoms attributable to their BSG; these individuals were older and more often had focal lesions. Thirty-one patients underwent treatment for their tumor, and 14 received CSF diversion only. Progression-free survival was ∼3 years shorter for children receiving tumor-directed therapy relative to those who had either no treatment or CSF diversion only. Overall survival was 85% for the tumor-directed therapy group, whereas no deaths were reported in the untreated or CSF diversion groups.

CONCLUSIONS

Unlike children with sporadically occurring BSGs, most children with NF1-BSGs were asymptomatic, and few individuals died from complications of their tumor. Those requiring tumor-directed treatment tended to be older children with focal lesions, and had clinically more aggressive disease relative to those who were not treated or underwent CSF diversion only.

Connections between constitutional mismatch repair deficiency syndrome and neurofibromatosis type 1

Constitutional mismatch repair (MMR) deficiency (CMMRD) is a rare childhood cancer susceptibility syndrome resulting from biallelic germline loss-of-function mutations in one of the MMR genes. Individuals with CMMRD have high risk to develop a broad spectrum of malignancies and frequently display features reminiscent of neurofibromatosis type 1 (NF1). Evaluation of the clinical findings of genetically proven CMMRD patients shows that not only multiple café-au-lait macules but also any of the diagnostic features of NF1 may be present in a CMMRD patient. This phenotypic overlap may lead to misdiagnosis of CMMRD patients as having NF1, which impedes adequate management of the patients and their families. The spectrum of CMMRD-associated childhood malignancies includes high-grade glioma, acute myeloid leukaemia or rhabdomyosarcoma, also reported as associated with NF1. Reported associations between NF1 and these malignancies are to a large extent based on studies that neither proved the presence of an NF1 germline mutation nor ruled-out CMMRD in the affected. Hence, these associations are challenged by our current knowledge of the phenotypic overlap between NF1 and CMMRD and should be re-evaluated in future studies. Recent advances in the diagnostics of CMMRD should render it possible to definitely state or refute this diagnosis in these individuals.

Neurocutaneous Syndromes and Brain Tumors

The etiology of most childhood cancer remains largely unknown, but is likely attributable to random or induced genetic aberrations in somatic tissue. However, a subset of children develops cancer in the setting of an underlying inheritable condition involving a germline genetic mutation or chromosomal aberration. The term "neurocutaneous syndrome" encompasses a group of multisystem, hereditary disorders that are associated with skin manifestations as well as central and/or peripheral nervous system lesions of variable severity. This review outlines the central nervous system tumors associated with underlying neurocutaneous disorders, including neurofibromatosis type 1, neurofibromatosis type 2, schwannomatosis, tuberous sclerosis complex, Von Hippel Lindau, and nevoid basal cell carcinoma syndrome. Recognizing the presence of an underlying syndrome is critically important to both optimizing clinical care and treatment as well as genetic counseling and monitoring of these affected patients and their families.

Histologically benign, clinically aggressive: Progressive non-optic pathway pilocytic astrocytomas in adults with NF1

Although optic pathway gliomas are the most common brain tumors associated with neurofibromatosis type 1 (NF1), extra-optic gliomas occur and may behave more aggressively with outcomes that differ by age. A retrospective case-control study was designed to describe the clinical course of adult NF1 patients with progressive extra-optic pilocytic astrocytomas (PAs) and compare to a pediatric cohort. Data for patients treated at the Johns Hopkins Comprehensive Neurofibromatosis Center from 2003 to 2013 were reviewed to identify cases (adults, age >18) and controls (pediatric, age <18) with clinically or radiographically progressive extra-optic PAs. Demographic, clinical, histologic, and radiographic data were collected. Three adult NF1 cases and four pediatric NF1 controls were identified. Mean age was 32.3 ± 9.5 years, 66% male (cases); 12.8 ± 4.2 years, 100% male (controls). Symptomatic progression occurred in two-of-three adults (67%) while the majority of pediatric patients presented with isolated radiographic progression (n = 3, 75%). Onset tended to be more rapid in adults (4 ± 1 vs. 14 ± 8.3 months, P = 0.10). Subtotal resection was the treatment for all pediatric patients. Radiotherapy (n = 2), chemotherapy (n = 2), and targeted, biologic agents (n = 2) were administered in adults. Although all pediatric patients are living, outcomes were universally poor in adults with progression to death in all (median survival 17.1 months, range 6.6-30.3). In conclusion, despite grade I histology, all three adult NF1 patients with progressive extra-optic PAs suffered an aggressive clinical course which was not seen in pediatric patients. Clinicians should be aware of this clinico-histologic discrepancy when counseling and managing adult NF1 patients with progressive extra-optic PAs. © 2016 Wiley Periodicals, Inc.

Recognition of genetic predisposition in pediatric cancer patients: An easy-to-use selection tool

Genetic predisposition for childhood cancer is under diagnosed. Identifying these patients may lead to therapy adjustments in case of syndrome-related increased toxicity or resistant disease and syndrome-specific screening programs may lead to early detection of a further independent malignancy. Cancer surveillance might also be warranted for affected relatives and detection of a genetic mutation can allow for reproductive counseling. Here we present an easy-to-use selection tool, based on a systematic review of pediatric cancer predisposing syndromes, to identify patients who may benefit from genetic counseling. The selection tool involves five questions concerning family history, the type of malignancy, multiple primary malignancies, specific features and excessive toxicity, which results in the selection of those patients that may benefit from referral to a clinical geneticist.

Neurofibromatosis type 1 and malignancy in childhood

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.

[Neurofibromatoses]

Neurofibromatosis type 1 (NF1) and type 2 (NF2) are hereditary autosomal dominant neurocutaneous disorders, the phacomatoses, characterized by the development of tumors derived from the cells of the peripheral nerve sheath and also includes schwannomatosis. Regarding the clinical and genetic aspects they are, however, two distinct entities which are described separately in the following review. In addition to the typical clinical presentation and diagnostic criteria, characteristic imaging findings are presented especially in terms of the role of imaging in the diagnosis, follow-up and assessment of prognostic aspects in these multisystemic disorders.

Intracerebral schwannomas: a rare disease with varying natural history

Although intracerebral schwannomas are typically regarded as benign intracranial tumors, malignancy and recurrence have been reported among patients harboring such neoplasms. The available literature consists of case reports and small series that present variable characteristics distinguishing these unusual lesions. Little advancement has been made to further the understanding and management of these tumors. The authors present 3 cases from their institution that highlight the difference between typical benign intracerebral schwannomas and histopathological variants that may portend more aggressive behavior. Also provided is a review of the literature in the hope of gaining a better understanding of these rare tumors.

Clinical sensitivity and specificity of multiple T2-hyperintensities on brain magnetic resonance imaging in diagnosis of neurofibromatosis type 1 in children: diagnostic accuracy study

Aim

To determine the prevalence, number, and location of multiple (≥2) T2-hyperintensities on brain magnetic resonance imaging (MRI) in children with neurofibromatosis type 1 (NF1) and their correlation with age, and to establish their sensitivity, specificity, and accuracy for the diagnosis of NF1 in children, especially in the early age (2-7 years).

Methods

We performed a cross-sectional study of 162 patients with NF1 from Croatian Neurofibromatosis Association Database and 163 control children between the ages of 2 and 18 years who underwent brain MRI between 1989 and 2009.

Results

Multiple T2-hyperintensities were present in 74% of NF1 patients and 1.8% of controls. They were mainly located in the basal ganglia, brainstem, and cerebellum and were significantly decreased in prevalence and number in the older age. T2-hyperintensities had excellent diagnostic accuracy with the area under the receiver operating characteristic (ROC) curve of 0.849 and 95% confidence interval (CI) of 0.805-0.886. The diagnostic sensitivity, specificity, and accuracy rate of T2-hyperintensities for NF1 were highest in the youngest age (2-7 years): 81% (95% CI 71%-89.1%), 99% (95% CI 92.3%-100%), and 85.8 (95% CI 83.3-93.8), respectively.

Conclusion

This study strongly suggests the inclusion of T2-hyperintensities on brain MRI on the list of diagnostic criteria for NF1, especially in children of early age, when the clinical penetration of the NF1 gene has not yet been completely finished.

Extended endoscopic endonasal skull base surgery: from the sella to the anterior and posterior cranial fossa

Skull base surgery has gone through significant changes with the development of extended endoscopic endonasal approaches over the last decade. Initially used for the transphenoidal removal of hypophyseal adenomas, the endoscopic transnasal approach gradually evolved into a way of accessing the whole ventral skull base. Improved visualization, avoidance of brain retraction, the ability to access directly tumours with minimal damage to critical neurosurgical structures as well lack of external scars are among its obvious benefits. However, it presents the surgeons with a number of challenges, including the need to deal endoscopically with potential arterial bleeding, complicated reconstruction requirements as well as the need for a true team approach. In this review drawing from our experience as well as published series, we present an overview of current indications, challenges and limitations of the expanded endonasal approaches to the skull base.

Tumors of central and peripheral nervous system associated with inherited genetic syndromes

There are several genetic syndromes that predispose to the development of tumors of the nervous system. In the present study, we provide a review of the tumors that are associated with neurofibromatosis type 1, neurofibromatosis type 2, tuberous sclerosis complex, von Hippel-Lindau disease, Li-Fraumeni syndrome, Cowden disease, Turcot syndrome, nevoid basal cell carcinoma syndrome (Gorlin syndrome) and rhabdoid predisposition syndrome, which are the most common.

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.

Pleomorphic xanthoastrocytoma and moyamoya disease in a patient with neurofibromatosis type 1 - case report -

A 32-year-old man with familial neurofibromatosis type 1 presented with a rare case of coexisting pleomorphic xanthoastrocytoma (PXA) and moyamoya disease manifesting as progressive right hemiparesis. Magnetic resonance (MR) imaging with gadolinium showed an enhanced mass lesion in the left basal ganglia extending to the left parietal lobe. Preoperative angiography showed severe stenosis of the bilateral internal carotid arteries, and moyamoya vessels. The patient underwent open biopsy. Histological examination showed the characteristic findings of PXA. After radiation therapy and chemotherapy, MR imaging showed decreased size and enhancement of the tumor, but his clinical condition worsened with generalized convulsions and consciousness disturbance. He died 1 year and 6 months after the first presentation. Autopsy findings demonstrated necrosis in the main mass and tumor cell dissemination without anaplastic change. The rare combination of PXA and moyamoya disease in the basal ganglia limited treatment options. Injured moyamoya vessels and ischemic condition might have caused tumor progression and dissemination. Radiation therapy, in combination with moyamoya disease, induced decreased cerebral blood flow (CBF) in the left frontal lobe. Tumor dissemination, CBF decrease, and hydrocephalus led to the clinical deterioration of this patient.

Primary cerebellar pilocytic astrocytoma with anaplastic features in a patient with neurofibromatosis type 1 - case report -

A 70-year-old woman with neurofibromatosis type 1 (NF-1) presented with a primary cerebellar pilocytic astrocytoma (PA) with anaplastic features manifesting as worsening headache and ataxia. Magnetic resonance (MR) imaging on admission showed a diffusely enhanced solid mass in the left cerebellar hemisphere, although MR imaging showed no abnormalities 2 years before admission. Histological examination after gross total removal of the tumor exhibited a biphasic pattern with marked Rosenthal fibers, together with some malignant features including frequent mitoses and invasive growth pattern. The final diagnosis was PA with anaplastic features. Previous PA cases with mitotic activity and endothelial proliferation, and/or palisading necrosis have been classified as anaplastic PA (or PA with anaplastic features). In the present case, the tumor histology corresponded to this designation. The present case indicates that PAs with anaplastic features can occur in patients with NF-1.

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.

Neurofibromatosis type 1 and high-grade tumors of the central nervous system

PURPOSE

Neurofibromatosis type 1 (NF1), a common genetic disorder, predisposes patients to the development of both benign and malignant tumors. Although the most common central nervous system (CNS) tumor is a low-grade pilocytic astrocytoma of the optic pathway, there have been sporadic reports of NF1 patients with more aggressive CNS lesions. We investigated the incidence of aggressive CNS lesions in NF1 patients at our institution.

METHODS

We conducted a retrospective review of all patients with NF1 and any CNS tumor being followed in the Children's Memorial Hospital NF1 Clinic.

RESULTS

Seven hundred forty patients with a diagnosis of NF1 were identified. Of these, 145 (20%) patients had CNS tumors, 99 (68%) of whom had optic pathway tumors (OPTs). Five patients (3%) were identified as having high-grade tumors, which consisted of anaplastic medulloblastoma (n = 1) and high-grade glioma (n = 4). The mean age at diagnosis of NF1 was 2 years. Three of the five patients had a history of an OPT prior to the development of their high-grade lesions. The clinical courses and treatment of these five patients varied. Currently, two patients are alive and receiving therapy at a mean of 10 months following diagnosis.

CONCLUSION

High-grade CNS tumors may occur in children with NF1. Although tumors in NF patients are generally benign, clinicians should have a high index of suspicion of malignancy in patients whose tumors are in an unusual location or behave in an uncharacteristically aggressive manner.

Inherited disorders as a risk factor and predictor of neurodevelopmental outcome in pediatric cancer

Each year in the United States, an average of one to two children per 10,000 develop cancer. The etiology of most childhood cancer remains largely unknown but is likely attributable to random or induced genetic aberrations in somatic tissue. However, a subset of children develops cancer in the setting of an underlying inheritable condition involving a germline genetic mutation or chromosomal aberration. Despite overall improved survival rates for children with cancer over recent decades, many patients experience neurological and neurocognitive complications during the course of their illness and/or as late effects of treatment. Improvements in therapy, longer survival times, and improved imaging techniques have all increased both the time that patients are at risk and the ability to detect such complications. How an underlying inherited disorder influences the incidence, timing, etiology, and treatment of such sequelae has not been extensively documented, but evidence exists for an increased risk for secondary malignancies and in some cases life-threatening sensitivity/toxicity to conventionally dosed cancer treatments, thus emphasizing the need for the early recognition of such syndromes. This review outlines the major tumor- and treatment-related neurodevelopmental sequelae in pediatric cancer patients, with particular attention to children with an underlying inheritable disorder.

Neurofibromatosis type 1 revisited

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition with a worldwide incidence of approximately 1 per 2500 to 3000 individuals. Caused by a germ-line-inactivating mutation in the NF1 gene on chromosome 17, the disease is associated with increased morbidity and mortality. In the past several years, significant progress has been made in standardizing management of the major clinical features of neurofibromatosis type 1. Moreover, improved understanding of how the neurofibromatosis type 1 protein, neurofibromin, regulates cell growth recently provided insight into the pathogenesis of the disease and has led to the development of new therapies. In this review, we describe the clinical manifestations, recent molecular and genetic findings, and current and developing therapies for managing clinical problems associated with neurofibromatosis type 1.

Visual outcome of a cohort of children with neurofibromatosis type 1 and optic pathway glioma followed by a pediatric neuro-oncology program

We evaluated the visual outcome of a cohort of children with neurofibromatosis type 1 (NF1) and optic pathway glioma (OPG) treated according to standardized therapeutic guidelines. The study population consisted of all consecutive patients with NF1 and OPG referred to a specialized pediatric neuro-oncology program between 1994 and 2004. Treatment was instituted only in cases of progressive disease or clinical deterioration. Treatment modalities were chemotherapy (based on vincristine/carboplatin) for children younger than 5 years and radiotherapy for all others. Ten boys and 10 girls (seven with a positive family history) entered the trial (median age at diagnosis of OPG, 29 months). At a median follow-up time of 78 months, seven patients had been treated with chemotherapy only, four with radiotherapy, and four with chemotherapy plus radiotherapy. Five patients were observed only. Currently, 18 are alive and two have died. Eight patients were treated for progressive visual loss in the face of stable disease, five for tumor volume increase without visual deterioration, and two for symptomatic tumor volume increase. At referral, six children had a visual acuity (VA) of < 30% in both eyes; eight children had 100% VA bilaterally. At referral, the visual field (VF) could be assessed in three children: One had VF loss in both eyes, one had VF loss in one eye, and one had normal VF. At last follow-up, eight children had VA < 20% in both eyes; only two children had 100% VA in both eyes. Among 11 children who had some visual function, three had VF loss in one eye and three in both eyes, and five had an intact VF. Contrast and color sensitivity were abnormal in seven and six patients, respectively. Thirteen children fell into the WHO hypovision category. In summary, among the 15 children treated, one had a definitive and two a mild improvement in VA. In conclusion, the visual outcome of this selected cohort of NF1 patients with OPG is unsatisfactory. A critical reappraisal of the therapeutic strategy adopted is needed.

Mice with GFAP-targeted loss of neurofibromin demonstrate increased axonal MET expression with aging

Neurofibromatosis 1 (NF1) is a common genetic disease that predisposes patients to peripheral nerve tumors and central nervous system (CNS) abnormalities including low-grade astrocytomas and cognitive disabilities. Using mice with glial fibrillary acidic protein (GFAP)-targeted Nf1 loss (Nf1(GFAP)CKO mice), we found that Nf1(-/-) astrocytes proliferate faster and are more invasive than wild-type astrocytes. In light of our previous finding that aberrant expression of the MET receptor tyrosine kinase contributes to the invasiveness of human NF1-associated malignant peripheral nerve sheath tumors, we sought to determine whether MET expression is aberrant in the brains of Nf1 mutant mice. We found that Nf1(-/-) astrocytes express slightly more MET than wild-type cells in vitro, but do not express elevated MET in situ. However, fiber tracts containing myelinated axons in the hippocampus, midbrain, cerebral cortex, and cerebellum express higher than normal levels of MET in older (> or =6 months) Nf1(GFAP)CKO mice. Both Nf1(GFAP)CKO and wild-type astrocytes induced MET expression in neurites of wild-type hippocampal neurons in vitro, suggesting that astrocyte-derived signals may induce MET in Nf1 mutant mice. Because the Nf1 gene product functions as a RAS GTPase, we examined MET expression in the brains of mice with GFAP-targeted constitutively active forms of RAS. MET was elevated in axonal fiber tracts in mice with active K-RAS but not H-RAS. Collectively, these data suggest that loss of Nf1 in either astrocytes or GFAP(+) neural progenitor cells results in increased axonal MET expression, which may contribute to the CNS abnormalities in children and adults with NF1.

Detection and measurement of neurofibromatosis-1 mouse optic glioma in vivo

One of the major limitations to preclinical mouse therapeutic evaluation is the inherent difficulty in imaging small tumors in vivo. We present a rapid and reliable method to detect optic glioma (OPG) in a mouse neurofibromatosis-1 model (Nf1(flox/mut)GFAP-Cre mice) in vivo using Manganese-Enhanced Magnetic Resonance Imaging (MEMRI). In a blinded study, 23 mice were chosen randomly from a cohort of Nf1(flox/mut)GFAP-Cre mice and two sets of age-matched controls. In all cases, OPG presence or absence was correctly identified. In addition, the OPG size and shape were accurately measured in vivo, facilitating the use of this model for preclinical drug studies.

Cutaneous manifestations of internal malignancy: diagnosis and management

An association between systemic malignancy and cutaneous manifestations has long been recognized. The cutaneous features that can occur are numerous and heterogeneous, and many different etiologic mechanisms are represented - from direct tumor invasion of skin or distant metastases to a wide variety of inflammatory dermatoses that may occur as paraneoplastic phenomena. In addition, there are a number of inherited syndromes that carry an increased risk of cutaneous as well as internal malignancies. While some of these inherited syndromes and paraneoplastic phenomena are exceedingly rare, all clinicians will be aware of the common cutaneous manifestations of advanced malignant disease such as generalized xerosis and pruritus. This review classifies these wide-ranging cutaneous manifestations of internal malignancy into five basic groups and provides practical advice regarding diagnosis and screening of patients who initially present with a cutaneous complaint. Also included is up-to-date information on two rapidly expanding and exciting areas of research that are likely to have far-reaching clinical implications: (i) clarification of underlying humoral mechanisms, for example, in the malignant carcinoid syndrome; and (ii) identification of an increasing number of specific genetic defects that confer a susceptibility to malignancy.Increased clinician awareness regarding the associations between these lesions and internal malignancy or inherited syndromes will facilitate screening and early diagnosis.

Neurosurgical implications of neurofibromatosis Type I in children

Neurofibromatosis Type 1 (NF1) is one of the most common inherited diseases in humans. It is caused by a mutation in the NF1 gene on chromosome 17, and is associated with numerous central and peripheral nervous system manifestations. Children with NF1 are at high risk of harboring numerous lesions that may require the attention of a neurosurgeon. Some of these include optic nerve gliomas, hydrocephalus, intraspinal tumors, and peripheral nerve tumors. Although most of the neoplasms that affect the brain, spine, and peripheral nerves of children are low-grade lesions, there is a small but real risk that some of these lesions may become high grade over time, requiring other forms of therapy than surgery alone. Other associated disorders that may result from NF1 in childhood include Chiari malformation Type I, scoliosis, and pulsating exophthalmos from the absence of the sphenoid wing. In this review, the major lesions that are found in children with NF1 are reviewed as well as the types of treatment that are offered by neurosurgeons and other members of the treating team. Today, optimum care of the child with NF1 is provided by a multidisciplinary team comprising neurosurgeons, neurologists, ophthalmologists, radiologists, orthopedic surgeons, and plastic surgeons.

Advances in treatment of pediatric brain tumors

The long-term survival of children with brain tumor has improved considerably in the last three decades, owing to advances in neuroimaging, neurosurgical, and radiation therapy modalities, coupled with the application of conventional chemotherapy. MRI, MR spectroscopy and diffusion-weighted MRI have contributed to more accurate diagnosis, prognostication and better treatment planning. Neurosurgical treatment has been advanced by the use of functional MRI, and intraoperative image-guided stereotactic techniques and electrophysiologic monitoring. The use of 3-D conformal and intensity-modulated radiation therapy, stereotactic radiosurgery, and radiosensitizing agents has made radiation therapy safer and more effective. Conventional chemotherapy, administered either alone or combined with radiation therapy has improved survival and quality of life of children with brain tumors. These improved outcomes have also occurred, due, in part, to their treatment on collaborative national and international studies. Recent promising diagnostic and therapeutic strategies have resulted from advances in understanding molecular brain tumor biology. Important new approaches include the refinement of drug-delivery strategies, the evaluation of biologic markers to stratify patients for optimal treatment and to exploit these molecular differences using "targeted" therapeutic strategies. These approaches include blocking tumor cell drug resistance mechanisms, immunotherapy, inhibition of molecular signal transduction pathways important in tumorigenesis, anti-angiogenic therapy, and gene therapy. The thrust of such approaches for children with brain tumors is especially directed at reducing the toxicity of therapy and improving quality-of-life, as well as increasing disease-free survival.

Optic pathway gliomas

Optic pathway gliomas represent approximately 5% of all pediatric intracranial tumors. While these tumors are most frequently low grade astrocytomas, they follow a highly variable clinical course, and accordingly, there is much debate regarding their optimal management. Their propensity to occur in very young children and infants further complicates selection of therapy. Historically, surgery and radiotherapy have played a primary role in management, however, in the last 15 years, chemotherapy has evolved into the first-line treatment of choice. Nonetheless, chemotherapy frequently fails, but serves to delay implementation of radiotherapy or surgery until the child has progressed neuropsychologically. An overall favorable prognosis for this tumor emphasizes the need for careful selection of therapy. Herein, we review the major features of optic pathway glioma, including epidemiology, pathology, therapeutic interventions, outcome, and treatment sequelae.

Neurosurgical implications of neurofibromatosis Type I in children

Neurofibromatosis Type 1 (NF1) is one of the most common inherited diseases in humans. It is caused by a mutation in the NF1 gene on chromosome 17, and is associated with numerous central and peripheral nervous system manifestations. Children with NF1 are at high risk of harboring numerous lesions that may require the attention of a neurosurgeon. Some of these include optic nerve gliomas, hydrocephalus, intraspinal tumors, and peripheral nerve tumors. Although most of the neoplasms that affect the brain, spine, and peripheral nerves of children are low-grade lesions, there is a small but real risk that some of these lesions may become high grade over time, requiring other forms of therapy than surgery alone. Other associated disorders that may result from NF1 in childhood include Chiari malformation Type I, scoliosis, and pulsating exophthalmos from the absence of the sphenoid wing. In this review, the major lesions that are found in children with NF1 are reviewed as well as the types of treatment that are offered by neurosurgeons and other members of the treating team. Today, optimum care of the child with NF1 is provided by a multidisciplinary team comprising neurosurgeons, neurologists, ophthalmologists, radiologists, orthopedic surgeons, and plastic surgeons.

The optic nerve: radiologic, clinical, and pathologic evaluation

The radiologic investigation of the optic nerve plays an integral part in the diagnostic evaluation of diverse lesions of the optic pathways including inflammatory diseases, vascular disorders and benign and malignant tumors and these radiologic modalities consist principally of CT and MR imaging and, in vascular lesions, MR angiography and conventional angiography. The selection of radiologic studies and their focus is based on the ophthalmologic examination where the ophthalmologist can often determine the suspected location of lesions in the anterior or posterior visual pathways. Furthermore, inspection of the eye, including adnexal structures and funduscopy, provides additional information in the clinical assessment of these patients. With technical advances in the last few years, CT and MR imaging can detect lesions and determine their location and extent with high sensitivity and specificity. This article discusses the radiologic, clinical, and pathologic evaluation of the optic nerve.

Ophthalmological manifestations in VHL and NF 1: pathological and diagnostic implications

Von Hippel-Lindau disease (VHL) and neurofibromatosis type 1 (NF 1) are hereditary multitumor syndromes that show associated ocular manifestations. Capillary retinal angioma, a benign vascular tumor, is the classical ocular lesion in VHL. It often appears as the first manifestation of the disease and may thus lead to the diagnosis of VHL. Since small angiomas can be treated easily by laser photocoagulation, a regular ocular screening of VHL patients is recommended. Ocular manifestations of NF 1 are more diverse as compared to VHL. Lisch nodules of the iris are an important diagnostic criteria of NF 1 since they can be found in almost every affected patient. Optic glioma can occur both intraorbitally and intracranially. The intraorbital form causes progressive protrusion of the globe and eventually blindness. Extension of the tumor beyond the chiasm worsens the prognosis quoad vitam. The hallmark of NF 1, namely cutaneous neurofibroma can cause visual impairment when affecting the skin of the eyelids. The rare intraorbital pexiform neurofibroma is associated with abnormal development of the orbital bones and infantile glaucoma. It may result in orbital mass effects and therefore may need surgical excision.

Multicentric pleomorphic xanthoastrocytoma in a patient with neurofibromatosis Type 1

✓ The authors report an unusual case of multicentric pleomorphic xanthoastrocytoma (PXA) in a 36-year-old woman with neurofibromatosis Type 1 (NF1). Both lesions were diagnosed as PXA but demonstrated different neuroimaging features and very different outcomes. Although the occipital lesion was cured surgically, the cerebellar tumor recurred three times and underwent malignant transformation into an anaplastic oligodendroglioma.

The authors discuss the causes of PXA and suggest that it could originate from common bipotential precursor cells with two phenotypes.

Brain Tumors in Neurofibromatosis

The neurofibromatoses are common neurocutaneous syndromes with multisystem involvement. These disorders place patients at increased risk for the development of malignancies. In particular, there is a predisposition to develop central nervous system and peripheral nervous system neoplasms. Distinct tumor types develop in association with neurofibromatosis type 1 (NF-1) different from those that are typically associated with neurofibromatosis type 2 (NF-2). In general, the tumors associated with NF-1 and NF-2 tend to demonstrate a more indolent course than similar tumors in patients without neurofibromatosis. An exception would be earlier presentation of tumors in each of these disorders. Management decisions are based on multiple factors. These include tumor location, presumed or known histology, and patient symptoms at time of diagnosis or evidence of progression either clinically or as demonstrated by neuroimaging. Once all of these factors have been weighed, therapeutic considerations include expectant observation, surgery, and radiation or chemotherapy. The overall philosophy of treatment is that of attempting to preserve neurologic function for as long as possible, because these are progressive disorders. At times, it may be preferable to keep interventions to a minimum in order to achieve this goal. A multidisciplinary approach is crucial in the care of these patients.