Type 1 neurofibromatosis and the pediatric patient

Impact of neurofibromatosis type 1 on quality of life using the Skindex-29 questionnaire quality of life in NF1

BACKGROUND

Neurofibromatosis type 1 (NF1) is one of the most common RASopathies predisposing affected patients to melanic lesions and benign tumors. NF1 is associated with considerable esthetic and functional burden negatively affecting the patient's quality of life (QoL). This study aims to assess the clinical features of NF1 patients and evaluate their impact on QoL. We identified NF1 patients from a public health database of a region in Spain. All patients underwent clinical and ophthalmological evaluation for NF1 features. We measured QoL using the Spanish version of the Skindex-29.

RESULTS

Forty patients fulfilled the NF1 National Institute of Health criteria when we recruited patients. The median age was 42.00 years (IQR 26.5 -53.75). The median total Skindex-29 score was 12.3 (IQR 5.9-22.4); (emotion: 15.0, IQR 5.0-37.5; symptoms 8.9, IQR 0.0-17.9 and functioning 8.3; IQR 0.5-18.3). Women and NF1 patients with lower educational levels were associated with poorer QoL scores. We identified itching and sleep troubles to influence NF1 patients' QoL negatively.

CONCLUSION

NF1 considerably influences the psychological well-being of NF1 patients. We observed that female and low-educated patients scored higher on the emotional dimension of the Skindex-29 and could, therefore, be more at risk of depression. We also pointed out some "minor symptoms" that negatively impact NF1 patients' QoL such, as itching and sleep troubles which doctors could treat if sought by doctors.

Modeling iPSC-derived human neurofibroma-like tumors in mice uncovers the heterogeneity of Schwann cells within plexiform neurofibromas

Plexiform neurofibromas (pNFs) are developmental tumors that appear in neurofibromatosis type 1 individuals, constituting a major source of morbidity and potentially transforming into a highly metastatic sarcoma (MPNST). pNFs arise after NF1 inactivation in a cell of the neural crest (NC)-Schwann cell (SC) lineage. Here, we develop an iPSC-based NC-SC in vitro differentiation system and construct a lineage expression roadmap for the analysis of different 2D and 3D NF models. The best model consists of generating heterotypic spheroids (neurofibromaspheres) composed of iPSC-derived differentiating NF1(-/-) SCs and NF1(+/-) pNF-derived fibroblasts (Fbs). Neurofibromaspheres form by maintaining highly proliferative NF1(-/-) cells committed to the NC-SC axis due to SC-SC and SC-Fb interactions, resulting in SC linage cells at different maturation points. Upon engraftment on the mouse sciatic nerve, neurofibromaspheres consistently generate human NF-like tumors. Analysis of expression roadmap genes in human pNF single-cell RNA-seq data uncovers the presence of SC subpopulations at distinct differentiation states.

Macrocephaly in the Primary Care Provider's Office

Macrocephaly is commonly encountered in the primary care provider's office. It is defined as an occipitofrontal circumference that is greater than 2 standard deviations above the mean for the child's given age. Macrocephaly is a nonspecific clinical finding that may be benign or require further evaluation. An algorithmic approach is useful for aiding in the clinical decision-making process to determine if further evaluation with neuroimaging is warranted. Abnormal findings may signify a harmful underlying cause, requiring referral to a genetic specialist or neurosurgeon.

SPRED proteins and their roles in signal transduction, development, and malignancy

The roles of SPRED proteins in signaling, development, and cancer are becoming increasingly recognized. SPRED proteins comprise an N-terminal EVH-1 domain, a central c-Kit-binding domain, and C-terminal SROUTY domain. They negatively regulate signaling from tyrosine kinases to the Ras-MAPK pathway. SPRED1 binds directly to both c-KIT and to the RasGAP, neurofibromin, whose function is completely dependent on this interaction. Loss-of-function mutations in SPRED1 occur in human cancers and cause the developmental disorder, Legius syndrome. Genetic ablation of SPRED genes in mice leads to behavioral problems, dwarfism, and multiple other phenotypes including increased risk of leukemia. In this review, we summarize and discuss biochemical, structural, and biological functions of these proteins including their roles in normal cell growth and differentiation and in human disease.

Cutting the Brakes on Ras-Cytoplasmic GAPs as Targets of Inactivation in Cancer

Simple Summary

GTPase-Activating Proteins (RasGAPs) are a group of structurally related proteins with a fundamental role in controlling the activity of Ras in normal and cancer cells. In particular, loss of function of RasGAPs may contribute to aberrant Ras activation in cancer. Here we review the multiple molecular mechanisms and factors that are involved in downregulating RasGAPs expression and functions in cancer. Additionally, we discuss how extracellular stimuli from the tumor microenvironment can control RasGAPs expression and activity in cancer cells and stromal cells, indirectly affecting Ras activation, with implications for cancer development and progression.

Abstract

The Ras pathway is frequently deregulated in cancer, actively contributing to tumor development and progression. Oncogenic activation of the Ras pathway is commonly due to point mutation of one of the three Ras genes, which occurs in almost one third of human cancers. In the absence of Ras mutation, the pathway is frequently activated by alternative means, including the loss of function of Ras inhibitors. Among Ras inhibitors, the GTPase-Activating Proteins (RasGAPs) are major players, given their ability to modulate multiple cancer-related pathways. In fact, most RasGAPs also have a multi-domain structure that allows them to act as scaffold or adaptor proteins, affecting additional oncogenic cascades. In cancer cells, various mechanisms can cause the loss of function of Ras inhibitors; here, we review the available evidence of RasGAP inactivation in cancer, with a specific focus on the mechanisms. We also consider extracellular inputs that can affect RasGAP levels and functions, implicating that specific conditions in the tumor microenvironment can foster or counteract Ras signaling through negative or positive modulation of RasGAPs. A better understanding of these conditions might have relevant clinical repercussions, since treatments to restore or enhance the function of RasGAPs in cancer would help circumvent the intrinsic difficulty of directly targeting the Ras protein.

Validating indicators of CNS disorders in a swine model of neurological disease

Genetically modified swine disease models are becoming increasingly important for studying molecular, physiological and pathological characteristics of human disorders. Given the limited history of these model systems, there remains a great need for proven molecular reagents in swine tissue. Here, to provide a resource for neurological models of disease, we validated antibodies by immunohistochemistry for use in examining central nervous system (CNS) markers in a recently developed miniswine model of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumor predisposition disorder stemming from mutations in NF1, a gene that encodes the Ras-GTPase activating protein neurofibromin. Patients classically present with benign neurofibromas throughout their bodies and can also present with neurological associated symptoms such as chronic pain, cognitive impairment, and behavioral abnormalities. As validated antibodies for immunohistochemistry applications are particularly difficult to find for swine models of neurological disease, we present immunostaining validation of antibodies implicated in glial inflammation (CD68), oligodendrocyte development (NG2, O4 and Olig2), and neuron differentiation and neurotransmission (doublecortin, GAD67, and tyrosine hydroxylase) by examining cellular localization and brain region specificity. Additionally, we confirm the utility of anti-GFAP, anti-Iba1, and anti-MBP antibodies, previously validated in swine, by testing their immunoreactivity across multiple brain regions in mutant NF1 samples. These immunostaining protocols for CNS markers provide a useful resource to the scientific community, furthering the utility of genetically modified miniswine for translational and clinical applications.

Endovascular Management of Neurofibromatosis Type I-Associated Vasculopathy: A Case Series and Brief Review of the Literature

Purpose:

Neurofibromatosis type 1 (NF1) is an autosomal-dominant disorder found in approximately 1 of every 3000 individuals. Neurofibromatosis type 1 can have vascular manifestations including aneurysms, stenoses, and arteriovenous malformations. The purpose of this article is to describe the clinical manifestations of NF1 vasculopathy, discuss therapeutic options, and highlight endovascular therapies from our institutional experience.

Materials and Methods:

The radiology information system was searched for cases of NF1. Cases with vasculopathy managed with endovascular therapies were included. Demographics, clinical histories, procedural details, and outcomes were recorded. A review of the literature for the management strategies of NF1 vasculopathy was performed.

Results:

Two pediatric patients with NF1 were identified, both of whom presented with hypertension found to be secondary to renal artery stenosis. One of the patients also had infrarenal aortic narrowing. Both patients were successfully treated with balloon angioplasty, resulting in improved blood pressures. The review of the literature identified case series of pharmacologic, surgical, and endovascular therapies, although, endovascular therapies appear to be preferred due to lower morbidity and mortality.

Conclusions:

NF1 vasculopathy is a rare condition that most often presents with hypertension due to renal artery stenosis. In these situations, endovascular management is the preferred approach.

A comparison of neuropsychological function between monozygotic twins with neurofibromatosis, type 1: A case report

Objective: Neurofibromatosis type 1 (NF-1) is an autosomal dominant genetic disorder that commonly presents with cognitive impairment and greater rates of learning disorders and academic difficulty compared to the general population. Investigations of neurological and physiological expression of NF-1 in monozygotic twins identified intrapair similarities and differences. Monozygotic twins with NF-1 have been found to have similar IQ scores as well as concordant diagnoses of attention-deficit/hyperactivity disorder and learning disabilities. There have been no previous reports on similarities and differences in neuropsychological profiles between monozygotic twins with NF-1. The purpose of this article is to examine the results of comprehensive neuropsychological evaluations for a pair of monozygotic twins with NF-1.Method: A pair of 19-year-old female, African-American monozygotic twins with NF-1 underwent neuropsychological evaluations in an outpatient clinic. Findings are reported following the CAse REport (CARE) guidelines.Results: The twins demonstrated similar impairment in processing speed, working memory, and attention span; however, differences also were found.Conclusions: Intrapair similarities and differences on neuropsychological assessment were found between monozygotic twins with NF-1. Primary deficits were suggestive of a frontal-subcortical pattern and could be consistent with remote neuroimaging. When differences did occur, performance was typically better for Twin A, who had also showed greater improvement on neuroimaging. Implications and directions for future research are discussed. Specifically, this case demonstrates the need for inclusion of neuropsychological assessment in studies of larger cohorts of monozygotic twins with NF-1 and correlation of neuropsychological findings with neuroimaging and postzygotic mutations.

Macrocephaly: Solving the Diagnostic Dilemma

Macrocephaly is a relatively common clinical condition affecting up to 5% of the pediatric population. It is defined as an abnormally large head with an occipitofrontal circumference greater than 2 standard deviations above the mean for a given age and sex. Megalencephaly refers exclusively to brain overgrowth exceeding twice the standard deviation. Macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, whereas megalencephaly is more often syndromic. Megalencephaly can be divided into 2 subtypes: metabolic and developmental, caused by genetic defects in cellular metabolism and alterations in signaling pathways, respectively. Neuroimaging plays an important role in the evaluation of macrocephaly, especially in the metabolic subtype which may not be overtly apparent clinically. This article outlines the diverse etiologies of macrocephaly, delineates their clinical and radiographic features, and suggests a clinicoradiological algorithm for evaluation.

A porcine model of neurofibromatosis type 1 that mimics the human disease

Loss of the NF1 tumor suppressor gene causes the autosomal dominant condition, neurofibromatosis type 1 (NF1). Children and adults with NF1 suffer from pathologies including benign and malignant tumors to cognitive deficits, seizures, growth abnormalities, and peripheral neuropathies. NF1 encodes neurofibromin, a Ras-GTPase activating protein, and NF1 mutations result in hyperactivated Ras signaling in patients. Existing NF1 mutant mice mimic individual aspects of NF1, but none comprehensively models the disease. We describe a potentially novel Yucatan miniswine model bearing a heterozygotic mutation in NF1 (exon 42 deletion) orthologous to a mutation found in NF1 patients. NF1+/ex42del miniswine phenocopy the wide range of manifestations seen in NF1 patients, including café au lait spots, neurofibromas, axillary freckling, and neurological defects in learning and memory. Molecular analyses verified reduced neurofibromin expression in swine NF1+/ex42del fibroblasts, as well as hyperactivation of Ras, as measured by increased expression of its downstream effectors, phosphorylated ERK1/2, SIAH, and the checkpoint regulators p53 and p21. Consistent with altered pain signaling in NF1, dysregulation of calcium and sodium channels was observed in dorsal root ganglia expressing mutant NF1. Thus, these NF1+/ex42del miniswine recapitulate the disease and provide a unique, much-needed tool to advance the study and treatment of NF1.

High prevalence of elevated blood pressure among children with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a common neurocutaneous disease characterized by café-au-lait spots, axillary and inguinal freckling, neurofibromas, and optic gliomas. Increased rates of hypertension (HTN) were reported among NF1 patients, however, the prevalence of HTN and pre-HTN in pediatric NF1 patients has not been clarified.

METHODS

Blood pressure (BP) measurements, weight, and renal ultrasound were assessed in 224 NF1 pediatric patients followed in a specialized NF1 clinic.

RESULTS

The cohort's mean age was 9.1 ± 4.1 years. Overweight and obesity were found in 12.9 and 10.3 % of them, respectively. BP was measured averagely 2.9 times per patient on different occasions. Blood pressure was in the pre-HTN and HTN ranges in 14.9 and 16.9 % of measurements, respectively. BP >95th was detected in 20.5 % at the first measurement. Of 114 children with at least three BP measurements, 18.4 % had two values in the HTN range and 6.14 % had at least three. Overweight was not associated with HTN among children with NF1. Urinary tract ultrasonographic abnormalities were detected in 6.8 % (11/161) of cases.

CONCLUSIONS

The prevalence of increased BP in pediatric NF1 is much higher than in the general pediatric population. BP has to be regularly assessed and managed in this high-risk population.

Perinatal (fetal and neonatal) astrocytoma: a review

INTRODUCTION

The purpose of this review is to document the various types of astrocytoma that occur in the fetus and neonate, their locations, initial findings, pathology, and outcome. Data are presented that show which patients are likely to survive or benefit from treatment compared with those who are unlikely to respond.

MATERIALS AND METHODS

One hundred one fetal and neonatal tumors were collected from the literature for study.

RESULTS

Macrocephaly and an intracranial mass were the most common initial findings. Overall, hydrocephalus and intracranial hemorrhage were next. Glioblastoma (GBM) was the most common neoplasm followed in order by subependymal giant cell astrocytoma (SEGA), low-grade astrocytoma, anaplastic astrocytoma, and desmoplastic infantile astrocytoma (DIA). Tumors were detected most often toward the end of the third trimester of pregnancy.

CONCLUSION

A number of patients were considered inoperable since their tumor occupied much of the intracranial cavity involving large areas of the brain. High-grade astrocytomas were more common than low-grade ones in this review. Fetuses and neonates with astrocytoma have a mixed prognosis ranging from as low as 20 % (GBM) to a high of 90 %. The overall survival was 47/101 or 46 %.

Bilateral Optic Pathway Ganglioglioma: The Fifth Case in the Literature

Gangliogliomas are mixed tumors which contain both glial and neuronal elements. The optic pathway is a very rare location for gangliogliomas, with less than 23 cases reported in the literature. Bilateral involvement of the entire optic pathway was reported in only 4 cases before. Because of similar radiological appearance of other pathological entities such as gliomas and craniopharyngiomas, histopathological diagnosis is essential. We report a ganglioglioma case that involved both optic pathways. A 12-year-old patient suffering from visual deterioration for 6 months was evaluated. After a visual field test and radiological examinations, a microsurgical biopsy procedure was performed. Pathological examination revealed dysplastic/neoplastic ganglion cells and neoplastic glial cells, and the diagnosis was a World Health Organization (WHO) grade 1 ganglioglioma. The patient is scheduled for adjuvant radiotherapy with the hope of prevention of progression.

Heat hyperalgesia and mechanical hypersensitivity induced by calcitonin gene-related peptide in a mouse model of neurofibromatosis

This study examined whether mice with a deficiency of neurofibromin, a Ras GTPase activating protein, exhibit a nociceptive phenotype and probed a possible contribution by calcitonin gene-related peptide. In the absence of inflammation, Nf1^+/− mice (B6.129S6 Nf1<tm1Fcr>/J) and wild type littermates responded comparably to heat or mechanical stimuli, except for a subtle enhanced mechanical sensitivity in female Nf1^+/− mice. Nociceptive phenotype was also examined after inflammation induced by capsaicin and formalin, which release endogenous calcitonin gene-related peptide. Intraplantar injection of capsaicin evoked comparable heat hyperalgesia and mechanical hypersensitivity in Nf1^+/− and wild type mice of both genders. Formalin injection caused a similar duration of licking in male Nf1^+/− and wild type mice. Female Nf1^+/− mice licked less than wild type mice, but displayed other nociceptive behaviors. In contrast, intraplantar injection of CGRP caused greater heat hyperalgesia in Nf1^+/− mice of both genders compared to wild type mice. Male Nf1^+/− mice also exhibited greater mechanical hypersensitivity; however, female Nf1^+/− mice exhibited less mechanical hypersensitivity than their wild type littermates. Transcripts for calcitonin gene-related peptide were similar in the dorsal root ganglia of both genotypes and genders. Transcripts for receptor activity-modifying protein-1, which is rate-limiting for the calcitonin gene-related peptide receptor, in the spinal cord were comparable for both genotypes and genders. The increased responsiveness to intraplantar calcitonin gene-related peptide suggests that the peripheral actions of calcitonin gene-related peptide are enhanced as a result of the neurofibromin deficit. The analgesic efficacy of calcitonin gene-related peptide receptor antagonists may therefore merit investigation in neurofibromatosis patients.

Ras protein/cAMP-dependent protein kinase signaling is negatively regulated by a deubiquitinating enzyme, Ubp3, in yeast

Ras proteins and cAMP-dependent protein kinase (protein kinase A, PKA) are important components of a nutrient signaling pathway that mediates cellular responses to glucose in yeast. The molecular mechanisms that regulate Ras/PKA-mediated signaling remain to be fully understood. Here, we provide evidence that Ras/PKA signaling is negatively regulated by a deubiquitinating enzyme, Ubp3. Disrupting the activity of Ubp3 leads to hyperactivation of PKA, as evidenced by much enhanced phosphorylation of PKA substrates, decreased accumulation of glycogen, larger cell size, and increased sensitivity to heat shock. Levels of intracellular cAMP and the active forms of Ras proteins are also elevated in the ubp3Δ mutant. Consistent with a possibility that the increased cAMP is responsible for the abnormal signaling behavior of the ubp3Δ mutant, overexpressing PDE2, which encodes a phosphodiesterase that hydrolyzes cAMP, significantly relieves the cell size increase and heat shock sensitivity of the mutant. Further analysis reveals that Ubp3 interacts with a Ras GTPase-accelerating protein, Ira2, and regulates its level of ubiquitination. Together, our data indicate that Ubp3 is a new regulator of the Ras/PKA signaling pathway and suggest that Ubp3 regulates this pathway by controlling the ubiquitination of Ras GTPase-accelerating protein Ira2.

Genetics of human enteric neuropathies

Knowledge of molecular mechanisms that underlie development of the enteric nervous system has greatly expanded in recent decades. Enteric neuropathies related to aberrant genetic development are thus becoming increasingly recognized. There has been no recent review of these often highly morbid disorders. This review highlights advances in knowledge of the molecular pathogenesis of these disorders from a clinical perspective. It includes diseases characterized by an infantile aganglionic Hirschsprung phenotype and those in which structural abnormalities are less pronounced. The implications for diagnosis, screening and possible reparative approaches are presented.

Decreased expression of neurofibromin contributes to epithelial-mesenchymal transition in neurofibromatosis type 1

Plexiform and/or dermal neurofibromas are nerve sheath tumors of the peripheral nervous system that are usually present in individuals with neurofibromatosis type 1 (NF1). Neurofibromas arise from Schwann cells with biallelic inactivation of NF1, the gene that encodes neurofibromin. This protein is responsible for regulation of the Ras-mediated pathway, which has been shown to play a crucial role in epithelial-to-mesenchymal transition (EMT). EMT is a biological process that occurs during embryogenesis and wound healing and is involved in pathological processes such as organ fibrosis and cancer metastasis. However, the relationship between neurofibromin and EMT has not been elucidated. We investigated whether the EMT-related signaling pathway was upregulated in NF1-associated neurofibromas and Schwann cells by assessing the expression levels of the EMT-related transcription factors Snail, Slug, Twist, ZEB1 and ZEB2. Immunohistochemical studies and quantitative reverse transcription polymerase chain reaction revealed an increase in the expression levels of EMT-related transcription factors in neurofibroma specimens and NF1-derived Schwann cells (sNF96.2). In addition, the silencing of NF1 by siRNA induced the expression of EMT-related transcription factors in normal human Schwann cells and in epithelial-like breast cancer cells. Our findings suggest that the loss of neurofibromin activated the EMT-related signaling pathway and that the excessive mesenchymal reaction may play a key role in the development of NF1-associated neurofibromas.

The RasGAP proteins Ira2 and neurofibromin are negatively regulated by Gpb1 in yeast and ETEA in humans

The neurofibromatosis type 1 (NF1) gene encodes the GTPase-activating protein (GAP) neurofibromin, which negatively regulates Ras activity. The yeast Saccharomyces cerevisiae has two neurofibromin homologs, Ira1 and Ira2. To understand how these proteins are regulated, we utilized an unbiased proteomics approach to identify Ira2 and neurofibromin binding partners. We demonstrate that the Gpb1/Krh2 protein binds and negatively regulates Ira2 by promoting its ubiquitin-dependent proteolysis. We extended our findings to show that in mammalian cells, the ETEA/UBXD8 protein directly interacts with and negatively regulates neurofibromin. ETEA contains both UBA and UBX domains. Overexpression of ETEA downregulates neurofibromin in human cells. Purified ETEA, but not a mutant of ETEA that lacks the UBX domain, ubiquitinates the neurofibromin GAP-related domain in vitro. Silencing of ETEA expression increases neurofibromin levels and downregulates Ras activity. These findings provide evidence for conserved ubiquitination pathways regulating the RasGAP proteins Ira2 (in yeast) and neurofibromin (in humans).

Health supervision for children with neurofibromatosis

Neurofibromatosis 1 is a multisystem disorder that primarily involves the skin and nervous system. Its population prevalence is 1 in 3500. The condition usually is recognized in early childhood, when cutaneous manifestations are apparent. Although neurofibromatosis 1 is associated with marked clinical variability, most affected children do well from the standpoint of their growth and development. Some features of neurofibromatosis 1 are present at birth, and others are age-related abnormalities of tissue proliferation, which necessitate periodic monitoring to address ongoing health and developmental needs and to minimize the risk of serious medical complications. This clinical report provides a review of the clinical criteria needed to establish a diagnosis, the inheritance pattern of neurofibromatosis 1, its major clinical and developmental manifestations, and guidelines for monitoring and providing intervention to maximize the growth, development, and health of an affected child.

An orthotopic xenograft model of intraneural NF1 MPNST suggests a potential association between steroid hormones and tumor cell proliferation

Malignant peripheral nerve sheath tumors (MPNST) are the most aggressive cancers associated with neurofibromatosis type 1 (NF1). Here we report a practical and reproducible model of intraneural NF1 MPNST, by orthotopic xenograft of an immortal human NF1 tumor-derived Schwann cell line into the sciatic nerves of female scid mice. Intraneural injection of the cell line sNF96.2 consistently produced MPNST-like tumors that were highly cellular and showed extensive intraneural growth. These xenografts had a high proliferative index, were angiogenic, had significant mast cell infiltration and rapidly dominated the host nerve. The histopathology of engrafted intraneural tumors was consistent with that of human NF1 MPNST. Xenograft tumors were readily examined by magnetic resonance imaging, which also was used to assess tumor vascularity. In addition, the intraneural proliferation of sNF96.2 cell tumors was decreased in ovariectomized mice, while replacement of estrogen or progesterone restored tumor cell proliferation. This suggests a potential role for steroid hormones in supporting tumor cell growth of this MPNST cell line in vivo. The controlled orthotopic implantation of sNF96.2 cells provides for the precise initiation of intraneural MPNST-like tumors in a model system suitable for therapeutic interventions, including inhibitors of angiogenesis and further study of steroid hormone effects on tumor cell growth.

Periapical cemental dysplasia is common in women with NF1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a genetic disorder with skeletal involvement. Periapical cemental dysplasia is a rare finding in the normal population.

METHOD

A total of 55 patients with NF1, 29 female and 26 male patients, were evaluated with orthopantomograms, supplemented with periapical radiographs if necessary. The vitality of the teeth was measured by two different testing methods.

RESULTS

A novel finding was the occurrence of cemental dysplasia affecting the periapical area of vital mandibular teeth in 8 adult women with NF1. Thus, cemental dysplasia was detected in 34.8% of the adult female NF1 patients, while cemental dysplasia was not present in men or children with NF1.

CONCLUSION

Periradicular cemental dysplasia is indeed a new NF1 related bone lesion type. Our finding suggests that this is the first reported sexual dimorphism in the manifestations of NF1. Cemental dysplasia of NF1 patients should not be confused with periapical findings caused by endodontic pathoses. The former do not require active therapy whereas in the latter root canal treatment is necessary.

Treatments for astrocytic tumors in children: current and emerging strategies

Strategies for the treatment of childhood cancer have changed considerably during the last 50 years and have led to dramatic improvements in long-term survival. Despite these accomplishments, CNS tumors remain the leading cause of death in pediatric oncology. Astrocytic tumors form the most common histologic group among childhood brain tumors. They are a heterogeneous group that from a practical therapeutic point of view can be subdivided into low-grade astrocytomas (LGA), optic pathway gliomas (OPG), high-grade astrocytomas (HGA), and brainstem gliomas (BSG). This article focuses on the practical application of treatments that lead to long-term survival, improved quality of life, and reduced long-term complications. Improvement in therapy has led to better outcomes for patients with LGA and OPG. Careful follow-up without any treatment is indicated for a small percentage of patients diagnosed with LGA with an indolent course including children with neurofibromatosis type 1 (NF1). Surgery is the main recommended treatment for children with resectable LGA. Radiation therapy is generally recommended for children with progressive LGA, or after failure of chemotherapy, accomplishing tumor control at 10 years in over 60% of patients. Cytotoxic chemotherapy is usually reserved for children who have had treatment failure with surgery and radiation therapy. It is also offered for children who are too young to be treated with radiation or to defer or avoid radiotherapy. Carboplatin and vincristine achieve 5% complete and 28% partial responses but the use of vincristine is criticized due to poor penetration of the CNS. A regimen of tioguanine, procarbazine, mitolactol, lomustine, and vincristine is frequently administered as an alternative to carboplatin and vincristine in LGA. The introduction of temozolomide has allowed better responses, including a 24% complete response rate compared with 0-5% complete response rates with the previous regimens. OPG are usually histologically LGA, and are treated with similar chemotherapy regimens. OPG is the most common type of brain tumor associated with NF1. Tumor growth in some of these patients is slow with no treatment recommended for an extended period of time. The prognosis for children with the remaining types of astrocytomas remains poor. Surgical resection is typically the first step in the treatment of HGA followed in older children by radiation therapy. The data regarding chemotherapy are mixed. Combination chemotherapy before or after radiation, including cisplatin, carmustine, cyclophosphamide, and vincristine or carboplatin, ifosfamide, cyclophosphamide, and etoposide has provided disappointing results. Clinical trials with temozolomide and agents directed against single targets have not shown substantially better results, but it is hoped that currently conducted studies will provide better outcomes. Diffuse intrinsic BSG are among the most difficult-to-treat brain tumors. Surgical treatment is not recommended for diffuse intrinsic BSG and standard radiation therapy is typically given in children aged >3 years. None of the numerous chemotherapy regimens, including temozolomide, has provided a significant response rate or an improvement in survival. It is expected that newer agents affecting multiple targets such as AEE-788 and antineoplastons, and combinations of single-targeted agents with chemotherapy will provide better results. Careful evaluation of histology, location of the tumor, patient age, and consideration of treatment-related morbidity play an important part in selecting between clinical observation, surgery, radiation, chemotherapy, or investigational agents. The goals of treatment for astrocytic tumors should extend well beyond objective responses and increased survival. Improvement of quality of life is an equally important objective of treatment. Radiation therapy and chemotherapy result in serious late toxicities.

From the Archives of the AFIP: neoplasms of the urinary bladder: radiologic-pathologic correlation

In the United States, primary bladder neoplasms account for 2%-6% of all tumors, with bladder cancer ranked as the fourth most common malignancy. Ninety-five percent of bladder neoplasms arise from the epithelium; the most common subtype is urothelial carcinoma, which accounts for 90% of cases. Squamous cell carcinoma accounts for 2%-15%, with rates varying widely according to geographic location. Adenocarcinoma (primary bladder, urachal, or metastatic) represents less than 2%. Bladder cancer typically occurs in men aged 50-70 years and is related to smoking or occupational exposure to carcinogens. Most urothelial neoplasms are low-grade papillary tumors, which tend to be multifocal and recur but have a relatively good prognosis. High-grade invasive tumors are less common and have a much poorer prognosis. Squamous cell carcinoma and adenocarcinoma occur in the setting of chronic bladder infection and irritation. Mesenchymal tumors represent the remaining 5% of bladder tumors, with the most common types being rhabdomyosarcoma, typically seen in children, and leiomyosarcoma, a disease of adults. Rarer mesenchymal tumors include paraganglioma, lymphoma, leiomyoma, and solitary fibrous tumor. Although imaging findings are not specific for these tumors, patterns of growth and tumor characteristics may allow differentiation. For accurate staging, computed tomography and magnetic resonance imaging are the modalities of choice.

Potential clinical role of FDG-PET in detecting sarcomatous transformation in von Recklinghausen's disease: a case study and review of the literature

BACKGROUND

The diagnosis of sarcomatous transformation of plexiform neurofibromas in Neurofibromatosis-1 (NF 1) is a clinical and radiological challenge. Considerable overlap exists in the clinical and the radiological characteristics between the benign enlarging neurofibromas and their counterparts undergoing malignant changes. Surgical biopsy to rule out suspicious malignant transformation is often a problem in deep seated lesions.

METHODS

We, in this paper, explore the clinical utility of FDG-PET in detecting and assessing this life threatening complication of neurofibromas. A case is described with FDG-PET and MRI documentation of such transformation and subsequent histopathological correlation. The case upholds the potential advantages of a FDG-PET over the conventional imaging modalities. A review of the existing literature is also carried out; a total of four published reports on this issue were identified in English literature by searches of Pubmed.

RESULTS AND CONCLUSION

FDG-PET appeared a reliable as well as sensitive noninvasive technique that might minimize unnecessary deep surgical biopsy to rule out malignant transformation in cases of NF-1 with features of enlargement of a preexisting peripheral nerve sheath tumour, pain or neurodeficit.

Neurocutaneous syndromes: behavioral features

Neurocutaneous syndromes are disorders characterized by a neurological abnormality and cutaneous manifestations. Three of the more common neurocutaneous syndromes are Sturge-Weber syndrome, tuberous sclerosis, and neurofibromatosis. This review focuses on the cognitive and behavioral features of these syndromes.

Spinal deformity in neurofibromatosis type-1: diagnosis and treatment

Spinal deformity is the commonest orthopaedic manifestation in neurofibromatosis type-1 and is categorized into dystrophic and non-dystrophic types. Management should be based on a meticulous assessment of the spine with plain radiography and magnetic resonance imaging (MRI) to rule out the presence of dysplastic features that will determine prognosis and surgical planning. MRI of the whole spine should also be routinely obtained to reveal undetected intraspinal lesions that could threaten scheduled surgical interventions. Non-dystrophic curvatures can be treated with similar decision-making criteria to those applied in the management of idiopathic scoliosis. However, close observation is necessary due to the possibility of modulation with further growth and due to the increased reported risk of pseudarthrosis after spinal fusion. The relentless progressive nature of dystrophic curves necessitates aggressive operative treatment, which often has a significant toll on the quality of life of affected patients through their early childhood. Bracing of dystrophic curves has been unsuccessful. Combined anterior/posterior spinal arthrodesis including the entire structural component of the deformity is indicated in most cases, particularly in the presence of associated sagittal imbalance. This should be performed using abundant autologous bone graft and segmental posterior instrumentation to minimize the risk of non-union and recurrence of the deformity.

Is a plexiform neurofibroma pathognomonic of neurofibromatosis type I?

OBJECTIVES/HYPOTHESIS

Several prominent textbooks have claimed that a plexiform neurofibroma is pathognomonic for neurofibromatosis type I. This is not in agreement with the National Institutes of Health criteria, which require two signs to be present, one of which can be a plexiform neurofibroma. Is a plexiform neurofibroma pathognomonic for neurofibromatosis type I?

STUDY DESIGN

Retrospective chart review.

METHODS

Fifty-one patients with surgically resected plexiform neurofibromas between the years 1991 and 2001 were identified, and their charts reviewed. The presence and absence of any manifestation of neurofibromatosis type I as detailed in the National Institutes of Health criteria were recorded. The pathology database at the Hospital for Sick Children (HSC) was searched retrospectively.

RESULTS

Five of the 51 patients had a single solitary plexiform neurofibroma. They were followed at the neurofibromatosis clinic at the HSC with regular detailed examinations and no other stigmata were found.

CONCLUSION

Although plexiform neurofibromas are highly suggestive of neurofibromatosis type I, they are not pathognomonic as claimed.

Neuroimaging findings in neurofibromatosis type 1 and 2

Neuroimaging, particularly MR imaging, plays an important role in the diagnosis and management of the patient with neurofibromatosis type 1 and 2. These phakomatoses are complex disorders affecting multiple cell types and multiple systems of the body with a wide range of expression. This article summarizes the neuroradiologic central nervous system findings in these neurocutaneous disorders.

Neuropsychological outcome in children with optic pathway tumours when first-line treatment is chemotherapy

Standard treatment of optic pathways gliomas consists of radiotherapy and surgery when feasible. Owing to the toxicity of irradiation, chemotherapy has emerged as an interesting therapeutic option, especially in young children. This study describes the neuropsychological profile of 27 children (aged between 1.5 and 15.7 years) with optic pathways gliomas treated with chemotherapy as first-line treatment. Eight of them also received radiotherapy as salvage treatment. Eight had neurofibromatosis type 1 (NF1). Intellectual outcome was preserved in children treated with chemotherapy only (mean=107±17) compared to children also receiving radiotherapy (mean IQ=88±24) or children having NF1 and treated with chemotherapy (mean IQ=80±13). Scores for abstract reasoning, mental arithmetic, chessboard/coding, perception, judgement of line orientation were lower in children irradiated than in those treated only by chemotherapy. Children with Nf1 showed subnormal IQ scores with marked impairment of short- and long-term memory. With respect to long-term neuropsychological outcome, our study shows that a chemotherapy-first strategy can preserve the intellectual outcome of these patients either by avoiding the need of radiotherapy or by delaying its use as much as possible.

I. Perinatal brain tumors: a review of 250 cases

Central nervous system tumors occur considerably less often in the fetus and neonate than in the older child. These tumors are not entirely the same as those found later in life. Their location, biologic behavior, response to therapy, and histologic types are different. Reports of 250 fetal and neonatal brain tumors were collected from the literature and studied for this review. The overall survival rate was 28%. The entire cranial cavity may be filled with tumor, and stillbirth is not uncommon. Macrocephaly was the most frequent presentation regardless of histology. Outcome is related to the size and location of the tumor, the histologic type, surgical resectability, and the condition of the infant at the time of diagnosis. Neonates with choroid plexus papillomas, gangliogliomas, and low-grade astrocytomas have the best prognosis, whereas those with teratomas and primitive neuroectodermal tumors have the worst prognosis.

Orthopaedic manifestations of neurofibromatosis in children: an update

Neurofibromatosis is one of the most common genetic disorders affecting mankind. Despite extensive basic science research, the diagnosis still is based largely on well-defined clinical criteria, which often present gradually during childhood. Approximately 50% of patients have significant musculoskeletal manifestations, with scoliosis and congenital pseudarthrosis of the tibia most common. Approximately 20% of children with Type I neurofibromatosis present with scoliosis with or without the classic dystrophic features, such as vertebral scalloping and rib penciling. Dystrophic curves portend rapid progression and require early fusion. Surgical treatment often is challenging because of the common presence of neurofibromas adjacent to the spinal cord, significant multiplanar deformity, and poor bone quality. Congenital pseudarthrosis of the tibia also continues to present significant difficulties. The use of a brace is the mainstay of early treatment, whereas intramedullary rodding commonly is used for operative fixation. Grafting of the free fibula and correction using techniques of distraction and compression histiogenesis with Ilizarov fixators have been reported for refractory cases with varying degrees of success. Multiple heroic, operative attempts may have a tremendous toll on the quality of life of affected children through their early childhood. In addition to these and other distinctive musculoskeletal lesions, affected children often suffer from various medical problems.

Neurofibromas in children with neurofibromatosis 1

Neurofibromatosis 1 is a common autosomal dominant disease reported in approximately 1 in 3000 individuals. Although some features of neurofibromatosis 1, such as café-au-lait spots and Lisch nodules, are clinically silent, neurofibromas cause a significant degree of morbidity, mortality, and cosmetic disfigurement. Childhood through early adulthood is a vulnerable period for the growth of these lesions. Neurofibromas are a heterogeneous group of benign tumors that grow from intraneural and extraneural tissues. These tumors take on different morphology, grow at variable rates, and occur in multiple locations. Symptoms arise as neurofibromas enlarge, compressing and distorting local structures. The unpredictable nature of neurofibromas has a serious impact on the quality of life of patients with neurofibromatosis 1, and their management is challenging for physicians. Surgical removal remains the mainstay of treatment. However, advances in the understanding of the genetics and pathogenesis of neurofibromatosis 1 have led to the development of promising new biologically directed therapies. The purpose of this review is to summarize the defining characteristics, incidence, clinical course, management options, and outcome of neurofibromas in children with neurofibromatosis 1.

Intracranial neoplasms in children with neurofibromatosis 1

Neurofibromatosis 1 is associated with an increased risk for the development of benign and malignant tumors involving neural and non-neural tissues. Children as well as adults with neurofibromatosis 1 are affected. Central nervous system neoplasms represent a significant portion of these malignancies and appear primarily in children less than 10 years of age. Optic pathway gliomas and brainstem gliomas are the most common intracranial neoplasms found in neurofibromatosis 1, although there also is an increased incidence of other brain tumors in this population. The majority of these intracranial neoplasms are benign pilocytic astrocytomas, which may behave in a less aggressive manner than histologically identical tumors in non-neurofibromatosis 1 patients. Owing to the indolent nature of these tumors, conservative management with close follow-up is recommended. When intervention is required, conventional treatment with surgery, radiation, or chemotherapy has been used with variable results. The current challenge lies in understanding the pathogenesis of gliomas in neurofibromatosis 1, which may lead to the development of biologically directed therapies with less associated morbidity and mortality for neurofibromatosis 1 as well as non-neurofibromatosis 1 children.

Cardiovascular disease in neurofibromatosis 1: report of the NF1 Cardiovascular Task Force

PURPOSE

Patients with neurofibromatosis 1 (NF1) are at increased risk for a variety of cardiovascular disorders, but the natural history and pathogenesis of these abnormalities are poorly understood.

METHODS

The National Neurofibromatosis Foundation convened an expert task force to review current knowledge about cardiovascular manifestations of NF1 and to make recommendations regarding clinical management and research priorities related to these features of the disease.

RESULTS

This report summarizes the NF1 Cardiovascular Task Force's current understanding of vasculopathy, hypertension, and congenital heart defects that occur in association with NF1. Recommendations are made regarding routine surveillance for cardiovascular disease and diagnostic evaluation and management of cardiovascular disorders in individuals with NF1.

CONCLUSION

Our understanding of the natural history and pathogenesis of cardiovascular disease in NF1 has improved substantially in the past few years, but many clinically important questions remain unanswered.

Molecular genetics in pediatric dermatology

The field of pediatric dermatology continues to be enriched by the insights offered through molecular genetics. For some genetic skin disorders, including neurofibromatosis, tuberous sclerosis complex, and several forms of epidermolysis bullosa, genetic research has resulted in an evolving understanding of the relationship between genotype and phenotype, with the ability to predict some of the features of these disorders on the basis of the genetic defect. However, widespread use of molecular genetics for diagnostic testing of these disorders has not been possible because of genetic heterogeneity, limited availability, and reduced sensitivity. The appropriate use of genetic services is emphasized in this, the molecular era.

Genetic aspects of cerebrovascular malformations

SUMMARY

In the last decade there have been fundamental advances in our understanding of the pathogenesis of vascular malformations. These advances have resulted from the application of molecular methods to identify disease genes, rather than from immunohistochemical or physiological studies. This presentation reviews the genetic basis of a variety of cerebral vascular malformations which occur as part of well-characterised diseases inherited in an autosomal dominant manner. These highlight the diversity of mechanisms which can perturb vascular development, and should have significant implications for the development of new therapies.

Site-specific DNA methylation in the neurofibromatosis (NF1) promoter interferes with binding of CREB and SP1 transcription factors

Tumour suppressor genes and growth regulatory genes are frequent targets for methylation defects that can result in aberrant expression and mutagenesis. We have established a methylation map of the promoter region of the neurofibromatosis (NF1) gene and demonstrated functional sensitivity for methylation at specific sites for the SP1 and CRE binding (CREB) proteins in the NF1 regulatory region. We evaluated the methylation status of CpG dinucleotides within five promoter subregions in the human and mouse homologues of the neurofibromatosis (NF1) genes. Three 5' subregions were found to be consistently methylated in all the tissues analysed. In contrast, DNA methylation was absent in the vicinity of the transcription start site bounded by SP1 recognition sequences. Gelshift assays showed that methylation specifically inhibits the CREB transcription factor from binding to its recognition site at the NF1 transcription start site. Furthermore, SP1 elements within the NF1 promoter are methylation sensitive, particularly when methylation is present on the antisense strand. We propose that for NF1 as with several other tumour suppressor genes, CpG methylation occurs in a complex, site-specific manner with the maintenance of a methylation-free promoter region bounded by SP1 binding sites that allow an accessible promoter to be retained. When these SP1 boundaries are breached, methylation can sweep in, rendering the promoter inaccessible for specific methylation-sensitive transcription factors and leading to a loss of functional integrity of the methylation-free CpG island.

Neurofibromatosis 1 in childhood

Neurofibromatosis 1 (NF1) is an autosomal-dominant disorder with an incidence of approximately 1 in 3,000. The cardinal features of the disorder are cafe au lait spots, axillary freckling, cutaneous neurofibromas, and iris hamartomas (Lisch nodules). Common complications include learning disability, scoliosis, and optic gliomas. Other complications (e.g., peripheral nerve malignancy, bony deformities, and epilepsy) are individually rare. The mainstay of care for patients with NF1 is anticipatory guidance, and the early detection and symptomatic treatment of disease complications. Counseling of patients and their families should provide a realistic overview of possible disease complications, while emphasizing that most individuals with NF1 lead healthy and productive lives. The gene for NF1 has been identified, and future cell biology research will focus on understanding the pathogenetic mechanisms that underly the diverse manifestations of the disorder.

MRI and nonverbal cognitive deficits in children with neurofibromatosis 1

Magnetic resonance imaging brain scans and neuropsychological assessments of 17 children who met the NIH consensus diagnostic criteria for neurofibromatosis Type 1 were carried out in order to determine if there is a relationship between presence of high intensity signal abnormalities on MRI scans and nonverbal cognitive deficits. Cranial MRI scans in 10 patients (58.8%) demonstrated high intensity signal abnormalities, most frequently in the cerebral peduncles. Fifteen patients had nonverbal cognitive deficits (88.2%), including difficulty judging the orientation of lines, matching complex visual stimulus configurations, recalling pictures of faces, as well as copying and drawing from memory a complex geometric figure. There was not a significant association between nonverbal neuropsychological deficits and presence of high intensity signal abnormalities on MRI scans, possibly because the location of these hyperintense abnormalities was typically below the level of the basal ganglia. These findings suggest that the high intensity signal lesions seen on the MRI scans of children with neurofibromatosis Type 1 do not predict or explain their nonverbal cognitive deficits.

Neurofibromatosis type 1--an update and review for the primary pediatrician

With an incidence of 1 in 3,000, neurofibromatosis type 1 (NF1), or von Recklinghausen disease, is one of the most common genetic disorders encountered by primary care physicians. NF1 is a multisystem disease that affects more than one million people worldwide (more than 80,000 in the United States). Although most pediatricians have patients with NF1 in their practices, many affected individuals go undiagnosed as children. This article is intended to facilitate the diagnosis and management of young patients with NF1.

Sporadic acute lymphocytic leukemia arising in a patient with neurofibromatosis and xanthogranulomatosis

We present a case report of a child who developed acute lymphoblastic leukemia, neurofibromatosis, optic glioma, and xanthogranulomatosis. This complex is unusual, not previously described, and appears to be a coincidence of different diseases. The importance of this case is that it may offer a clue to the genetic base of neurofibrosis syndromes including leukemic associations.

Neurofibromatosis type I gene mutation in a patient with features of LEOPARD syndrome

Multiple lentigines (LEOPARD) syndrome has been delineated as an autosomal dominant disorder with lentigines, cardiac abnormalities, variable mental retardation, and typical craniofacial features as the most characteristic findings. LEOPARD syndrome shows a great clinical overlap with neurofibromatosis type 1 (NF1). In this report we describe a de novo missense mutation (M 1035R) in exon 18 of the NF1 gene in a young woman with a prior diagnosis of LEOPARD syndrome. We hypothesize that some patients now diagnosed with LEOPARD syndrome have in fact a mutation in the NF1 gene, whereas in other patients with LEOPARD syndrome, a different gene might be involved.

Neurocutaneous syndromes associated with pigmentary skin lesions

Tremendous strides have been made in our understanding of genetic disorders, including those that involve both the skin and the nervous system. The list of well-established neurocutaneous syndromes has increased during a few decades from a few classical phakomatoses to more than 30 entities. The dermatologist has the opportunity to facilitate precise diagnosis and optimal care for these patients by recognition of the cutaneous markers for these diseases. We have attempted to provide an overview of some recent advances in those syndromes manifested by pigmentary skin changes, emphasizing the clinical spectrum of each disorder and providing guidelines for an approach to management.

Encephalocraniocutaneous lipomatosis with a mutation in the NF1 gene

Encephalocraniocutaneous lipomatosis (ECCL) is a congenital hamartomatous disorder characterised by unilateral skin lesions, lipomas, and ipsilateral ophthamological and cerebral malformations. The disorder is thought to represent a localised form of Proteus syndrome. In this report, a child is described with ECCL and a de novo nonsense mutation in exon 29 (S1745X) of the neurofibromatosis type 1 (NF1) gene. Although it is possible that both ECCL and NF1 occur coincidentally in this patient, we favour the hypothesis that in exceptional cases a mutation in the NF1 gene might give rise to severe congenital malformations such as ECCL. Possible pathogenetic mechanisms for these malformations are discussed.