The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2

Historical Development of Diagnostic Criteria for NF2-related Schwannomatosis

NF2-related schwannomatosis (NF2; previously termed neurofibromatosis type 2) is a tumor-prone disorder characterized by development of multiple schwannomas and meningiomas. The diagnostic criteria of NF2 have been regularly revised. Clinical criteria for NF2 were first formulated at the National Institutes of Health Consensus Conference in 1987 and revised in 1990. Revised criteria were also proposed by the Manchester group in 1992 and by the National Neurofibromatosis Foundation (NNFF) in 1997. The 2011 Baser criteria improved the sensitivity of diagnostic criteria, particularly for patients without bilateral vestibular schwannomas. Revisions to the Manchester criteria were published in 2019, with replacement of "glioma" by "ependymoma," removal of "neurofibroma," addition of an age limit of 70 years for development of vestibular schwannomas, and introduction of molecular criteria, which led to the most widely used criteria. In 2022, the criteria were reviewed and updated by the international committee of NF experts. In addition to changes in diagnostic criteria, the committee recommended the use of "schwannomatosis" as an umbrella term for conditions that predispose to schwannomas. Each type of schwannomatosis was classified by the gene containing the disease-causing pathogenic variant. Molecular data from NF2 patients led to further clarification of the diagnostic criteria for NF2 mosaic phenotypes. Given all these changes, the diagnostic criteria of NF2 may be confusing. Herein, to help healthcare professionals who diagnose NF2 conditions in the clinical setting, we review the historical development of diagnostic criteria.

Quality of life in patients with neurofibromatosis type 1: a nationwide database study in Japan from 2015 to 2019

BACKGROUND

This study examined the association between dermatological, neurological, and bone manifestations of neurofibromatosis type 1 (NF1) and quality of life (QoL) in patients with NF1 using a nationwide database of all patients who newly claimed for medical expense subsidies in Japan from 2015 to 2019.

METHODS

The Japanese Ministry of Health, Labour and Welfare provided the "National Database of Designated Intractable Diseases of Japan" containing clinical and personal records ("Medical Certificates of Designated Intractable Diseases") of all patients with NF1 following approval of the study protocol. To examine the association between the severity of symptoms and QoL, multinominal logistic regression analyses were performed, adjusted for potential confounders.

RESULTS

The final study population consisted of 1,487 patients (775 females and 712 males; mean (standard deviation) age, 45.4 (17.9) years). More than 50% and nearly 45% of participants were recorded as having moderate or severe "pain/discomfort" and "anxiety/depression," respectively. The severity of neurological symptoms was significantly associated with all components of QoL, whereas the severity of dermatological symptoms was significantly associated with only moderate or severe subjective and mental health-related components of QoL, and the severity of bone lesions was associated with only moderate or severe physical health-related components of QoL. Subjective and mental health-related components of QoL tended to be deteriorated more than physical health-related components of QoL in younger and female patients.

CONCLUSIONS

Severities of neurological and dermatological symptoms were significantly associated with subjective and mental health-related components of QoL, while the severity of bone symptoms was associated with only moderate and severe deterioration of physical health-related components of QoL.

MiR-27a-3p/miR-27b-3p Promotes Neurofibromatosis Type 1 via Targeting of NF1

The dysregulation of microRNAs (miRNAs) is a crucial molecular signature of disease development. The potential implication of miRNAs in neurofibromatosis type 1 (NF1) remains poorly investigated. The expression levels of miR-27a-3p, miR-27b-3p, and neurofibromin 1 (NF1) were detected by real-time quantitative polymerase chain reaction (RT-qPCR) analysis. The functional roles of miR-27a-3p and miR-27b-3p in NF1 were explored by CCK8 (Cell Counting Kit-8), 5-ethynyl-2'-deoxyuridine (EdU), terminal deoxynucleoitidyl transferase dUTP nick-end labeling (TUNEL), and transwell assays. Luciferase reporter, RNA pull-down, and RNA binding protein immunoprecipitation (RIP) assays were employed to study the probable target relationship between miRNA and messenger RNA (mRNA). MiR-27b-3p and miR-27a-3p were upregulated in dermal and plexiform human Schwann cells (HSC) from NF1 neurofibromas as well as cell lines of malignant peripheral nerve sheath tumors (MPNSTs). MiR-27a-3p/miR-27b-3p mimics promoted the proliferative, migratory, and invasive ability of dermal HSC and MPNST cell ST88-14, while inhibiting the apoptotic capacity. MiR-27a-3p/miR-27b-3p inhibitors elicited the opposite impacts on the above cellular behaviors in dermal HSC and ST88-14. Intriguingly, NF1 was revealed to be the target of both miR-27a-3p and miR-27b-3p, and was negatively modulated by them. MiR-27a-3p/miR-27b-3p upregulation suppressed the expression of NF1 in dermal HSC and ST88-14. Furthermore, NF1 depletion counterbalanced the functional alteration induced by miR-27a-3p/miR-27b-3p inhibition. Our study suggests that both miR-27b-3p and miR-27a-3p are involved in upstream molecular activity responsible for the depletion of NF1, representing promising targets for therapeutic application in NF1.

Stem Cell-Derived Models of Neural Crest Are Essential to Understand Melanoma Progression and Therapy Resistance

During development, neural crest (NC) cells are early precursors of several lineages including melanocytes. Along their differentiation from multipotent cells to mature melanocytes, NC cells will go through successive steps which require either proliferative or motile capacities. For example, they will undergo Epithelial to Mesenchymal Transition (EMT) in order the separate from the neural tube and migrate to their final location in the epidermis (Larribere and Utikal, 2013; Skrypek et al., 2017). The differentiated melanocytes are the cells of origin of melanoma tumors which progress through several stages such as radial growth phase, vertical growth phase, metastasis formation, and often resistance to current therapies. Interestingly, depending on the stage of the disease, melanoma tumor cells share phenotypes with NC cells (proliferative, motile, EMT). These phenotypes are tightly controlled by specific signaling pathways and transcription factors (TFs) which tend to be reactivated during the onset of melanoma. In this review, we summarize first the main TFs which control these common phenotypes. Then, we focus on the existing strategies used to generate human NCs. Finally we discuss how identification and regulation of NC-associated genes provide an additional approach to improving current melanoma targeted therapies.

Endocrine implications of neurofibromatosis 1 in childhood

In 1882, von Recklinghausen described a group of patients with multiple tumors arising from the 'endoneurium' of peripheral nerves, and called them 'neurofibromas'. The term von Recklinghausen disease was used up to the end of the 20th century, when the gene of neurofibromatosis (NF1) was cloned on chromosome 17q11.2. The gene product is a cytoplasmic protein termed neurofibromin, regulating proliferation and maturation of both glial and neuronal progenitors during embryogenesis. Loss of neurofibromin function determines the hyperactivation of the proto-oncogene RAS, leading to an increased risk of tumor formation, predominantly affecting the skin, bone and the nervous system. NF1 is clinically and genetically distinct from neurofibromatosis type 2, characterized by bilateral vestibular schwannomas and other nervous system tumors. An increased incidence of central precocious puberty, diencephalic syndrome, GH deficiency and GH hypersecretion has been described in NF1 children. These conditions are commonly complications of optic pathway gliomas (OPG) involving the hypothalamic and sellar region. Nevertheless, these endocrine disorders have been observed also in children without evidence of OPG at magnetic resonance imaging. Clinical and laboratory follow-up is crucial in all children with NF1, particularly in those with an OPG, aiming at the early identification of signs suggestive of secondary endocrine alterations.

A case of neurofibromatosis type 1 coinciding with bilateral pheochromocytomas, multiple gastrointestinal stromal tumors, and malignant peripheral nerve sheath tumor

Neurofibromatosis type 1 (NF1) is associated with benign and malignant neoplasms, but the coincidence of abdominal neoplasms is rare. A 65-year-old woman with NF1 had episodes of nausea, tachycardia, hypertension, and loss of consciousness. Bilateral adrenal tumors were detected by abdominal computed tomography, and plasma and urinary catecholamine levels were elevated. Open bilateral adrenalectomy and histological findings revealed bilateral pheochromocytomas (PCCs). Furthermore, malignant peripheral nerve sheath tumor (MPNST) and multiple gastrointestinal stromal tumors (GISTs) were incidentally found in the abdominal cavity. Early diagnosis of abdominal neoplasms in NF1 patients is important because of the risk of malignancy, organic complications and hemorrhagic-obstructive complications.

Empirical development of improved diagnostic criteria for neurofibromatosis 2

PURPOSE

Four sets of clinical diagnostic criteria have been proposed for neurofibromatosis 2, but all have low sensitivity at the time of initial clinical assessment for the disease among patients with a negative family history who do not present with bilateral vestibular schwannomas. We have empirically developed and tested an improved set of diagnostic criteria that uses current understanding of the natural history and genetic characteristics of neurofibromatosis 2 to increase sensitivity while maintaining very high specificity.

METHODS

We used data from the UK Neurofibromatosis 2 Registry and Kaplan-Meier curves to estimate frequencies of clinical features at various ages among patients with or without unequivocal neurofibromatosis 2. On the basis of this analysis, we developed the Baser criteria, a new diagnostic system that incorporates genetic testing and gives more weight to the most characteristic features and to those that occur before 30 years of age.

RESULTS

In an independent validation subset of patients with unequivocal neurofibromatosis 2, the Baser criteria increased diagnostic sensitivity to 79% (9-15% greater than previous sets of criteria) while maintaining 100% specificity at the age at onset of the first characteristic sign of neurofibromatosis 2.

CONCLUSION

The Baser criteria permit early diagnosis in a greater proportion of patients with neurofibromatosis 2 than previous sets of diagnostic criteria.

Recurrent abdominal complaints caused by a cecal neurofibroma: A case report

Gastrointestinal involvement of neurofibromatosis type 1 (NF1, Von Recklinghausen’s disease) is generally associated with the upper gastrointestinal tract. Abdominal manifestation of NF1 includes several tumors such as malignant peripheral nerve sheath tumors, gastrointestinal stromal tumors and ampulla of vater tumors. However, colonic involvement in NF1 patients is rare. We report a case of a patient presenting with dysphagia, weight loss, intermittent abdominal pain and constipation caused by a single cecal neurofibroma obstructing the ileocecal valve. Also gastrointestinal involvement of the lower tract should be considered in patients with NF1 presenting with abdominal complaints.

LEOPARD syndrome (PTPN11, T468M) in three boys fulfilling neurofibromatosis type 1 clinical criteria

Noonan syndrome (NS) and neurofibromatosis type 1 (NF1) are well-defined entities. The association of both disorders is called neurofibromatosis-Noonan syndrome (NFNS), a disorder that has been related to mutations in the NF1 gene. Both NS and NFNS display phenotypic overlapping with LEOPARD syndrome (LS), and differential diagnosis between these two entities often represents a challenge for clinicians. We report on three patients (two brothers and a not-related patient) diagnosed as having NFNS. They fulfilled NF1 diagnostic criteria and had some features of NS. The three of them had hypertophic cardiomyopathy while neurofibromas, Lisch nodules, and unidentified bright objects on MRI were absent. PTPN11 gene assays revealed a T468M mutation, typical of LS. Thorough clinical examinations of the patients revealed multiple lentigines, which were considered to be freckling in the initial evaluation. We conclude that NF1 clinical criteria should be used with caution in patients with features of NS. Patients with hyperpigmented cutaneous spots associated with cardiac anomalies, even if fulfilling the minimal NF1 criteria for diagnosis, should be strongly considered for LS diagnosis.

Quality of life and depression assessment in nevoid basal cell carcinoma syndrome

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS) is a rare genetic disease which causes a variety of dermatological lesions, especially basal cell carcinomas (BCCs), often on the face, neck, and head.

METHODS

Persons attending a national NBCCS support group meeting were asked to participate in survey-based assessments of quality of life and depressive symptoms. Inclusion criteria required a self-reported NBCCS diagnosis, voluntary agreement to participate, and age over 18 years. Exclusion criteria included cognitive impairment. Skin-related quality of life was assessed with Skindex-29, completed by 32 participants. Depressive symptomatology was determined with the Center for Epidemiological Studies Depression Scale (CES-D), completed by 18 participants. Sociodemographic, medical, and social variables were also analyzed.

RESULTS

Median Skindex-29 scores for the emotions, symptoms, and functioning scales were 42.50, 32.14, and 28.13, respectively (means: 41.17, 37.05, and 29.30, respectively). These scores were slightly higher than those observed in patients with neurofibromatosis type 1, a similar genetic disease with skin symptoms. The CES-D scores (median = 15.50, mean = 17.50) suggested that 50% of participants had significant depressive symptomatology. Variables showing moderate associations with the scores included diet, number of affected family members, and treatment type. Interestingly, the number of BCCs had no effect.

CONCLUSIONS

Nevoid basal cell carcinoma syndrome impacts the quality of life of its subjects in a similar manner to other genodermatoses. Depressive symptoms are particularly prevalent. Several demographic, medical, and social characteristics affect these outcomes. Thus, the psychological impact of this disorder should be evaluated in the course of considering the care of persons with NBCCS.

Effects of splicing mutations on NF2-transcripts: transcript analysis and information theoretic predictions

This study examined the effects of 22 putative splicing mutations in the NF2 gene by means of transcript analysis and information theory based prediction. Fourteen mutations were within the dinucleotide acceptor and donor regions, often referred to as (AG/GT) sequences. Six were outside these dinucleotide regions but within the more broadly defined splicing regions used in the information theory based model. Two others were in introns and outside the broadly defined regions. Transcript analysis revealed exon skipping or activation of one or more cryptic splicing sites for 17 mutations. No alterations were found for the two intronic mutations and for three mutations in the broadly defined splicing regions. Concordance and partial concordance between the calculated predictions and the results of transcript analysis were found for 14 and 6 mutations, respectively. For two mutations, the predicted alteration was not found in the transcripts. Our results demonstrate that the effects of splicing mutations in NF2 are often complex and that information theory based analysis is helpful in elucidating the consequences of these mutations.

A novel NF1 gene mutation in an Italian family with neurofibromatosis type 1

PURPOSE

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder with an estimated incidence of one in 3,500 births. Clinically, NF1 is characterized by café-au-lait (CAL) spots, neurofibromas, freckling of the axillary or inguinal region, Lisch nodules, optic nerve glioma, and bone dysplasias. NF1 is caused by inactivating mutations of the 17q11.2-located NF1 gene. We present a clinical and molecular study of an Italian family with NF1.

METHODS

The proband, a 10-year-old boy, showed large CAL spots and freckling on the axillary region and plexiform neurofibromas on the right side only. His father (47 years old) showed, in addition to the similar signs, numerous neurofibromas of various sizes on his thorax, abdomen, back, and shoulder. Two additional family members (a brother and a sister of the proband) presented only small CAL spots. The coding exons of NF1 gene were analyzed for mutations by denaturing high-performance liquid chromatography and sequencing in all family members.

RESULTS

The mutational analysis of the NF1 gene revealed a novel frameshift insertion mutation in exon 4c (c.654 ins A) in all affected family members. This novel mutation creates a shift on the reading frame starting at codon 218 and leads to the introduction of a premature stop at codon 227.

CONCLUSIONS

The segregation of the mutation with the affected phenotype and its absence in the 200 normal chromosomes suggest that it is responsible for the NF1 phenotype.

Mortality associated with neurofibromatosis type 1: a study based on Italian death certificates (1995-2006)

BACKGROUND

Persons affected by neurofibromatosis type 1 (NF1) have a decreased survival, yet information on NF1-associated mortality is limited. METHODS/AIM: The National Mortality Database and individual Multiple-Causes-of-Death records were used to estimate NF1-associated mortality in Italy in the period 1995-2006, to compare the distribution of age at death (as a proxy of survival) to that of the general population and to evaluate the relation between NF1 and other medical conditions by determining whether the distribution of underlying causes of NF1-associated deaths differs from that of general population.

RESULTS

Of the nearly 6.75 million deaths in the study period, 632 had a diagnosis of NF1, yet for nearly three-fourths of them the underlying cause was not coded as neurofibromatosis. The age distribution showed that NF1-associated deaths also occurred among the elderly, though mortality in early ages was high. The mean age for NF1-associated death was approximately 20 years lower than that for the general population. The gender differential may suggest that women are affected by more severe NF1-related complications, or they may simply reflect a greater tendency for NF1 to be reported on the death certificates of young women. Regarding the relation with other medical conditions, we found an excess, as the underlying cause of death, for malignant neoplasm of connective and other soft tissue and brain, but not for other sites. We also found an excess for obstructive chronic bronchitis and musculoskeletal system diseases among elderly persons.

CONCLUSION

This is the first nationally representative population-based study on NF1-associated mortality in Italy. It stresses the importance of the Multiple-Causes-of-Death Database in providing a more complete picture of mortality for conditions that are frequently not recorded as the underlying cause of death, or to study complex chronic diseases or diseases that have no specific International Classification of Diseases code, such as NF1. It also highlights the usefulness of already available data when a surveillance system is not fully operational.

Gonadotropin-dependent precocious puberty: neoplastic causes and endocrine considerations

Premature activation of the hypothalamic-pituitary-gonadal (HPG) axis manifests as gonadotropin-dependent precocious puberty. The mechanisms behind HPG activation are complex and a clear etiology for early activation is often not elucidated. Though collectively uncommon, the neoplastic and developmental causes of gonadotropin-dependent precocious puberty are very important to consider, as a delay in diagnosis may lead to adverse patient outcomes. The intent of the current paper is to review the neoplastic and developmental causes of gonadotropin-dependent precocious puberty. We discuss the common CNS lesions and human chorionic gonadotropin-secreting tumors that cause sexual precocity, review the relationship between therapeutic radiation and gonadotropin-dependent precocious puberty, and finally, provide an overview of the therapies available for height preservation in this unique patient population.

Spinal ependymomas in neurofibromatosis Type 2: a retrospective analysis of 55 patients

OBJECT

The aim of this paper was to define the clinical characteristics of spinal ependymomas associated with neurofibromatosis Type 2 (NF2).

METHODS

The authors retrospectively reviewed the clinical records of patients with NF2 who had imaging findings consistent with ependymomas and were seen at Massachusetts General Hospital between 1994 and 2007. Clinical characteristics of these patients were obtained from hospital records, imaging studies, surgical reports, and pathology reports. Mutational analysis of the NF2 gene was performed in 37 of 44 unrelated patients.

RESULTS

Fifty-five patients met inclusion criteria for the study. The median age at diagnosis of NF2 was 21 years; the median time after diagnosis until identification of ependymomas was 5 years. Multiple ependymomas were present in 58% of patients. The most common site of involvement was the cervical cord or cervicomedullary junction (86% of imaging studies), followed by the thoracic and lumbar cords (62% and 8%, respectively). The majority of patients had no symptoms related to their tumors (42 patients [76%]). After a median follow-up of 50 months, surgery was performed in 11 patients (20%) for symptomatic progression (indications for surgery). Mutational analysis of the NF2 gene detected alterations in 28 (76%) of 37 unrelated patients, with nonsense and frameshift mutations accounting for 64% of detected mutations. The high rate of truncating mutations may help explain the high tumor burden in these patients.

CONCLUSIONS

Neurofibromatosis Type 2-related ependymomas exhibit an indolent growth pattern with tumor progression limited to a minority of patients. The authors believe that surveillance is reasonable for asymptomatic ependymomas, including those with cystic areas that expand the cord. For symptomatic tumors, resection may be warranted depending on age, overall clinical status, and ease of resectability.

Rare and unusual endocrine cancer syndromes with mutated genes

The study of a number of rare familial syndromes associated with endocrine tumor development has led to the identification of genes involved in the development of these tumors. Major advances have expanded our understanding of the pathophysiology of these rare endocrine tumors, resulting in the elucidation of causative genes in rare familial diseases and a better understanding of the signaling pathways implicated in endocrine cancers. Recognition of the familial syndrome associated with a particular patient's endocrine tumor has important implications in terms of prognosis, screening of family members, and screening for associated conditions.

Bone resorption in syndromes of the Ras/MAPK pathway

Disorders of the Ras/mitogen-activated protein kinase (MAPK) pathway have an overlapping skeletal phenotype (e.g. scoliosis, osteopenia). The Ras proteins regulate cell proliferation and differentiation and neurofibromatosis type 1 (NF1) individuals have osteoclast hyperactivity and increased bone resorption as measured by urine pyridinium crosslinks [pyridinoline (Pyd) and deoxypyridinoline (Dpd)]. Pyd and Dpd are hydroxylysine-derived crosslinks of collagen found in bone and cartilage and excreted in the urine. Dpd is most abundant in bone. The aim of this study was to evaluate if other syndromes of the Ras/MAPK pathway have increased bone resorption, which may impact the skeletal phenotype. Participants were individuals with Noonan syndrome (n = 14), Costello syndrome (n = 21), and cardiofaciocutaneous (CFC) syndrome (n = 14). Pyridinium crosslinks from two consecutive first morning urines were extracted after acid hydrolysis and analyzed by high performance liquid chromatography. Three separate analyses of covariance were performed to compare Pyd, Dpd, and Dpd/Pyd ratio of each group to controls after controlling for age. Data were compared to 99 healthy controls. The Dpd and the Dpd/Pyd ratio were elevated (p < 0.0001) in all three conditions compared to controls suggesting that collagen degradation was predominantly from bone. The data suggest that the Ras/MAPK signal transduction pathway is important in bone homeostasis.

Pediatric 25-hydroxyvitamin D concentrations in neurofibromatosis type 1

OBJECTIVE

Low 25-hydroxyvitamin D (25OHD) concentrations have been associated with tumors and osteopenia or fractures in adults with neurofibromatosis type 1 (NF1). We report 25OHD concentrations in 109 children with NF1 and 218 controls matched for age, sex, geographic location, and time of year.

METHODS

Children with NF1 were recruited (n=109; 2-17 years), and clinical data and dual-energy X-ray absorptiometry measurements were obtained. 25OHD concentrations were measured in subjects and controls.

RESULTS

More NF1 individuals (50%) were in the 25OHD insufficient or deficient range (<30 ng/mL) (1 ng/mL = 2.496 nmol/L) compared to controls (36%) (p = 0.0129). 25OHD concentrations were higher in individuals with neurofibromas after controlling for age (p = 0.0393), and were negatively associated with whole-body subtotal bone mineral density (BMD) z-scores (p = 0.0385).

CONCLUSIONS

More children with NF1 had 25OHD concentrations <30 ng/mL, potentially because of increased pigmentation and/or decreased sunlight exposure. In contrast to adults, decreased 25OHD concentrations were not associated with neurofibromas, and there was no positive association between 25OHD and BMD.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

CONCLUSION

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

HRCT findings in the lungs of non-smokers with neurofibromatosis

PURPOSE

Interstitial lung disease in neurofibromatosis (NF) has been disputed and attributed to smoking-related changes. The aim of this study was to describe HRCT findings in the lungs of non-smokers with NF.

MATERIALS AND METHODS

Six never-smokers with NF underwent lung HRCT. Two radiologists evaluated the HRCT scans and a final decision was reached by consensus. The HRCT scans were analyzed with regard to the number, size, location (upper, middle or lower lung zone) and distribution (peripheral and central) of lung cysts and the presence of ground-glass density centrilobular micronodules.

RESULTS

All patients with NF had small (2-18 mm) thin wall cysts and upper-lobe predominant patchy areas of ground-glass density centrilobular micronodules. In five cases, there were 3-17 cysts and in one there were numerous (>100). Lung cysts were central (1), subpleural (1) and in both locations (4).

CONCLUSION

Interstitial lung disease in NF is not associated with smoking and may be entirely asymptomatic. HRCT may reveal small cysts, with barely perceptible walls therefore not representing emphysema and occasionally a minimal micronodular pattern of ground glass opacity. There was no radiologic evidence of lung fibrosis, honeycombing or severe bullous disease.

Neurofibromatosis type 1 associated with bilateral central giant cell granuloma of the mandible

Neurofibromatosis type 1, or von Recklinghausen disease, is one of the most common hereditary neurocutaneous disorders in humans. Clinically, Neurofibromatosis type 1 is characterized by café-au-lait spots, freckling, skin neurofibroma, plexiform neurofibroma, bony defects, Lisch nodules and tumors of the central nervous system. Central giant cell granuloma is a benign central lesion of bone, primarily involving the jaws, of variably aggressive nature characterized by aggregates of multinucleated giant cells in a background of cellular vascular fibrous connective tissue and spindle-shaped mononuclear stromal cells. The association between neurofibromatosis and central giant cell granuloma has been reported in the literature. A case of mandibular bilateral central giant cell granuloma in a patient with Neurofibromatosis type 1 was conservatively but successfully treated by adequate surgical curettage of mandibular bone lesions.

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.

Podoplanin and CD34 in peripheral nerve sheath tumours: focus on neurofibromatosis 1-associated atypical neurofibroma

Patients suffering from neurofibromatosis type 1 and 2 (NF1 and NF2) are the main risk groups to develop peripheral nerve sheath tumours (PNSTs). In the present study, adhesion molecules CD34 and podoplanin were assessed in regard to their value for tumour classification and as indicators for tumour progression. A total of 103 NF1-, NF2- and schwannomatosis-associated neurofibromas, schwannomas and malignant peripheral nerve sheath tumours (MPNST), as well as 20 sporadic vestibular schwannomas and 9 control tissue samples, were labelled immunohistochemically for detection of podoplanin and CD34. CD34 was shown to be expressed in MPNST and all benign PNSTs except for the compact cellular parts of both, schwannomas and atypical neurofibromas. Podoplanin showed an inverse expression pattern to CD34 labelling mainly the compact parts of schwannoma and atypical neurofibroma. MPNSTs were characterized by strong podoplanin staining at the invasive front. NF1-patients who suffered from atypical neurofibromas did not develop MPNST at a higher frequency than other NF1-patients, although these tumours expressed podoplanin. Ki-67 proliferation indices did not differ significantly between neurofibromas, atypical neurofibromas and schwannomas. In accordance with other studies, CD34 was found to be of limited value for classification and grading of PNST due to its ubiquitous expression. Podoplanin expression in schwannoma and atypical neurofibroma adds to other phenotypic and genotypic similarities between these tumours, like nuclear atypia, regressive changes and euploid polyploidisation. Podoplanin expression in atypical neurofibroma was not associated with tumour progression towards MPNST.

Phenotypic variability among café-au-lait macules in neurofibromatosis type 1

BACKGROUND

Café-au-lait macules (CALMs) in neurofibromatosis type 1 (NF1) are an early and accessible phenotype in NF1, but have not been extensively studied.

OBJECTIVE

We sought to more fully characterize the phenotype of CALMs in patients with NF1.

METHODS

In all, 24 patients with a diagnosis of NF1 confirmed through clinical diagnosis or molecular genetic testing were recruited from patients seen in the genetics department at the University of Alabama at Birmingham. CALM locations were mapped using standard digital photography. Pigment intensity was measured with a narrowband spectrophotometer, which estimates the relative amount of melanin based on its absorption of visible light. The major response was defined as the difference between the mean melanin from the CALM and the mean melanin from the surrounding skin. The major response for each spot was compared with spots within an individual and across individuals in the study population.

RESULTS

There was significant variability of the major response, primarily attributable to intrapersonal variability (48.4%, P < .0001) and secondly to interpersonal variability (33.0%, P < .0094). Subsequent analysis based on genetic mutation type showed significantly darker spots in individuals with germline mutations leading to haploinsufficiency.

LIMITATIONS

The study was performed on a small population of patients and the method has not yet been used extensively for this purpose.

CONCLUSIONS

CALMs vary in pigment intensity not only across individuals, but also within individuals and this variability was unrelated to sun exposure. Further studies may help elucidate the molecular basis of this finding, leading to an increased understanding of the pathogenesis of CALMs in NF1.

Endocrine tumours in neurofibromatosis type 1, tuberous sclerosis and related syndromes

Neurofibromatosis type 1 (NF-1) and tuberous sclerosis complex (TSC) are two familial syndromes known as phakomatoses that may be associated with endocrine tumours. These hereditary cutaneous conditions affect the central nervous system and are characterised by the development of hamartomas. Over the past 20 years, there have been major advances in our understanding of the molecular basis of these diseases. Both NF-1 and TSC are disorders of unregulated progression through the cell cycle, in which causative genes behave as tumour suppressor genes. The pathogenesis of these familial syndromes is linked by the shared regulation of a common pathway, the protein kinase mammalian target of rapamycin (mTOR). Additional related disorders that also converge on the mTOR pathway include Peutz-Jeghers syndrome and Cowden syndrome. All of these inherited cancer syndromes are associated with characteristic skin findings that offer a clue to their recognition and treatment. The discovery of mTOR inhibitors has led to a possible new therapeutic modality for patients with endocrine tumours as part of these familial syndromes.

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

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

Inherited predisposition to gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract and are a relatively recently identified category of mesenchymal tumors. Germline mutations in a number of different genes predispose to GIST. This article discusses familial GIST syndrome, Carney triad, Carney-Stratakis syndrome, and neurofibromatosis type 1, and addresses the recognition of an inherited predisposition in GIST patients.

[Solitary neurofibroma presenting as a tender soft-to-firm tumor at the temporal head region masquerading as temporal arteritis]

We reported a 59-year-old woman who had complained of right temporalgia for 5 years. She was first diagnosed with a carious tooth, but treatment did not alleviate the pain. She then developed right facial pain and numbness at the right side of the tongue tip. In spite of repetitive examinations and medications, temporalgia worsened in August, 2007. Neurological examination on admission revealed a palpable soft-to-firm tumor with tenderness at the right temporal head region, right facial pain radiating to the right forehead induced by tapping on the middle of the forehead, and dysesthesia at the right tip of the tongue, C-reactive protein was negative and erythrocyte sedimentation rate was normal. Ultrasonographic examination showed beads-like tumors with low-echoic lesions without blood flow. MRI demonstrated multiple small ovoid lesions in the right subcutaneous tissue of the right temporal head. Although we initially suspected temporal arteritis, these findings were contrary. Tumor biopsy finally revealed solitary neurofibroma of the right auriculotemporal nerve. A sporadic localized intraneural neurofibroma at the extracranial region is an uncommon entity. Furthermore, nerve sheath tumors of the trigeminal nerve rarely manifest with intermittent painful burning or crawling sensations simulating trigeminal neuralgia. The present case manifested as a tumor with tenderness at the right auriculotemporal nerve and mimicked temporal arteritis. Therefore, it is important to understand that neurofibroma of the auriculotemporal nerve can mimic temporal arteritis and manifest with trigeminal neuralgia-like pain.

Hereditary colorectal cancer: MYH-associated polyposis and other newly identified disorders

Historically, discussions of familial adenomatous polyposis and hereditary non-polyposis colon cancer have dominated lectures and writings on hereditary predisposition to colorectal cancer. In the last decade, the subject has grown well beyond the two entities. In this paper, five topics relevant to genetic risk assessment for colorectal cancer are reviewed. These include the autosomal recessive MYH-associated polyposis, hyperplastic polyposis and serrated pathway syndrome, the association of autosomal dominant juvenile polyposis with hereditary hemorrhagic telangiectasia, familial colorectal cancer type X, and the syndrome of biallelic DNA mismatch repair gene mutations. Knowledge of these entities may assist clinicians to recognize and manage cases that do not fit into the more common syndromes of colorectal cancer predisposition.

Genetics and molecular pathology of neuroendocrine gastrointestinal and pancreatic tumors (gastroenteropancreatic neuroendocrine tumors)

PURPOSE OF REVIEW

Gastrointestinal and pancreatic neuroendocrine tumors (GEP-NETs) originate from cells of the diffuse endocrine system. Most GEP-NETs are sporadic, however, some of them, especially pancreatic endocrine tumors, may occur as part of familial syndromes. The genetic and molecular pathology of neuroendocrine tumor development is incomplete and remains largely unknown. However, the WHO classification introduced in clinical practice will give more insight into genetic and molecular changes related to tumor subtypes.

RECENT FINDINGS

In sporadic endocrine pancreatic tumors, losses of chromosome 1 and 11q as well as gain on 9q appear to be early invents in development of pancreatic tumors because they are already present in small tumors. Multiple genetic defects may accumulate with time and result in pancreatic neuroendocrine tumor progression and malignancy. Gastrointestinal endocrine tumors (carcinoids) show predominantly genetic alterations concentrated on chromosome 18. There are losses of the entire chromosome as well as smaller deletions. The most frequently reported mutated gene in gastrointestinal neuroendocrine tumors is b-catenin. Overexpression of cyclin D1 and cMyc has also been reported. Recently, a set of genes NAP1L1, MAGE-2D and MTA1 has been correlated with malignant behavior of small intestinal carcinoids.

SUMMARY

Molecular profiling of GEP-NETs demonstrates that pancreatic endocrine tumors and gastrointestinal neuroendocrine tumors (carcinoids) display different genetic changes and should, therefore, be considered to be different tumor entities; thereby, also differently managed clinically. Although the number of genetic changes is higher in malignant tumors, we are still far away from defining a malignant profile in GEP-NETs.

Congenital pseudarthrosis of neurofibromatosis type 1: impaired osteoblast differentiation and function and altered NF1 gene expression

Three patients with neurofibromatosis 1 (NF1) were operated for congenital pseudarthrosis (PA) of the tibia. Three non-NF1 patients served as reference. Both NF1 mRNA and protein were detected in the PAs and in rows of osteoblasts and numerous osteoclasts next to the NF1-related PA arguing against inactivation of both NF1 alleles in the resident cells. Analyses on mesenchymal stem cells (MSCs) cultured from the red bone marrow of 1) next to PA of the affected NF1 tibiae, 2) the non-affected NF1 iliac crest of the same patients, and from 3) non-NF1 bone marrow demonstrated that the potential to form bone in vitro was the lowest in cells from the affected NF1-tibiae. The latter cells also displayed reduced levels of NF1 mRNA and protein, and upregulated phosphorylated p44/42 MAPK levels, consistent with an upregulated Ras-pathway. An exhaustive NF1 gene analysis detected constitutional mutation in each case, but no second hits or loss of heterozygosity were found. However, one patient displayed a mutation resulting in two potential active splice sites ultimately affecting exon 6. Interestingly, only one of the respective transcripts was detected in cells from the iliac crest, but two novel transcripts were detected in MSCs cultured from site next to PA. This finding may identify a novel mechanism how a single NF1 gene mutation may exert distinct effects on separate anatomical locations. The molecular pathogenesis of NF1-related PA apparently may not be entirely explained by second mutations or loss of heterozygosity of the NF1 gene.

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.

Giant Chiari network mimics intracardiac tumor in a case of neurofibramatosis

Neurocutaneos syndromes are associated with cardiac or heart related extracardiac tumors, as well as atrial or ventricular septal defect, pulmonary stenosis, coarctation of aorta. Here we describe a case of neurofibromatosis with valvular pulmonary stenosis and giant Chiari network, which mimics a right atrial tumor originating from interatrial septum.

Diffusion-weighted imaging of retroperitoneal malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1

We present the diffusion-weighted imaging (DWI) findings for a malignant peripheral nerve sheath tumor arising in a retroperitoneal plexiform neurofibroma in a patient with neurofibromatosis type 1. Signal intensity of the malignant area was high on DWI and low on the apparent diffusion coefficient map and differed from findings for the benign area. DWI enabled clear differentiation between malignant and benign areas of the tumor.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are rare autosomal-dominant conditions that predispose affected individuals to benign and malignant tumors of the pituitary, thyroid, parathyroids, adrenals, endocrine pancreas, paraganglia, or nonendocrine organs. The classic MEN syndromes include MEN type 1 and MEN type 2. However, several other hereditary conditions should also be considered in the category of MEN: von Hippel-Lindau syndrome, the familial paraganglioma syndromes, Cowden syndrome, Carney complex, and hyperparathyroidism jaw-tumor syndrome. In addition, researchers are becoming aware of other familial endocrine neoplasia syndromes with an unknown genetic basis that might also fall into the category of MEN. This article reviews the clinical features, diagnosis, and surgical management of the various MEN syndromes and genetic risk assessment for patients presenting with one or more endocrine neoplasms.

Myelopathy in a 6-year-old girl caused by neurofibromatosis Type 1: a case report

BACKGROUND CONTEXT

Even when there is radiological evidence of spinal involvement, young patients with neurofibromatosis Type 1 (NF-1) seldom have symptoms. We report the case of a child who developed rapidly progressive myelopathy.

PURPOSE

To describe a technique used to prevent postoperative spinal deformity and instability, after removal of a dumbbell-shaped tumor in a 6-year-old child.

STUDY DESIGN

Case report.

PATIENT SAMPLE

A 6-year-old female.

METHODS

Retrospective case review.

RESULTS

The patient underwent a resection of the cervical dumbbell tumor using an osteoplastic laminectomy technique to prevent postoperative spinal deformity. At 2-year follow-up, there was no clinical or radiographic evidence of complications or spinal kyphotic deformity.

CONCLUSIONS

The case of a 6-year-old girl with cervical myelopathy caused by NF-1 was reported. The tumor was removed after osteoplastic laminectomy, which could prevent postoperative kyphotic deformity.

Immunohistochemical analysis supports a role for INI1/SMARCB1 in hereditary forms of schwannomas, but not in solitary, sporadic schwannomas

The INI1/SMARCB1 protein product (INI1), a component of a transcription complex, was recently implicated in the pathogenesis of schwannomas in two members of a single family with familial schwannomatosis. Tumors were found to have both constitutional and somatic mutations of the SMARCB1 gene and showed a mosaic pattern of loss of INI1 expression by immunohistochemistry, suggesting a tumor composition of mixed null and haploinsufficient cells. To determine if this finding could be extended to all tumors arising in familial schwannomatosis, and how it compares with other multiple schwannoma syndromes [sporadic schwannomatosis and neurofibromatosis 2 (NF2)] as well as to sporadic, solitary schwannomas, we performed an immunohistochemistry analysis on 45 schwannomas from patients with multiple schwannoma syndromes and on 38 solitary, sporadic schwannomas from non-syndromic patients. A mosaic pattern of INI1 expression was seen in 93% of tumors from familial schwannomatosis patients, 55% of tumors from sporadic schwannomatosis, 83% of NF2-associated tumors and only 5% of solitary, sporadic schwannomas. These results confirm a role for INI1/SMARCB1 in multiple schwannoma syndromes and suggest that a different pathway of tumorigenesis occurs in solitary, sporadic tumors.

[NF1 mutation analysis in a Chinese family with neuro- fibromatosis type]

A Chinese family affected with autosomal dominant disorder-neurofibromatosis type I was identified in this study. Linkage analysis was performed, and DNA sequencing for whole coding region of NF1 was carried out to identify the disease-causing mutation. The disease gene of the Chinese NF1 family was linked to NF1 locus, and a nonsense mutation, G1336X in the NF1 gene was identified. This mutation truncates the NF1 protein by 1 483 amino acid residues at the C-terminus, and is co-segregate with all the patients, but not present in unaffected individuals in the family. The present study demonstrated that G1336X mutation in the NF1 gene cause Neurofibromatosis type I in the family. To our knowledge, this mutation is firstly reported in Chinese population.

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.

Auditory brainstem implants: current state and future directions with special reference to the subtonsillar approach for implantation

In this article, the authors describe the current state of the auditory brainstem implant (ABI), comparing it to that of the cochlear implant (CI). The CI restores hearing by stimulating the cochlear nerve in the cochlea in patients whose deafness has been caused by inner ear disease; the ABI restores hearing by stimulating the cochlear nucleus of the brainstem in patients who are deaf because of bilateral cochlear nerve dysfunction. Up to now, about 500 patients worldwide have undergone ABI and had their hearing restored, most of whom suffer from neurofibromatosis type 2. Hearing performance, however, is not as good as that offered by the cochlear implant. To improve the quality of hearing, new techniques such as advanced coding strategies and penetrating electrodes, are now being introduced.

Modeling NF2 with human arachnoidal and meningioma cell culture systems: NF2 silencing reflects the benign character of tumor growth

Meningiomas, common tumors arising from arachnoidal cells of the meninges, may occur sporadically, or in association with the inherited disorder, neurofibromatosis 2 (NF2). Most sporadic meningiomas result from NF2 inactivation, resulting in loss of tumor suppressor merlin, implicated in regulating membrane-cytoskeletal organization. To investigate merlin function in an authentic target cell type for NF2 tumor formation, we established primary cultures from genetically-matched meningioma and normal arachnoidal tissues. Our studies revealed novel and distinct cell biological and biochemical properties unique to merlin-deficient meningioma cells compared to merlin-expressing arachnoidal and meningioma cells, and other NF2-deficient cell types. Merlin-deficient meningioma cells displayed cytoskeletal and cell contact defects, altered cell morphology and growth properties, most notably cell senescence, implicating the activation of senescence pathways in limiting benign meningioma growth. Merlin suppression by RNAi in arachnoidal cells replicated merlin-deficient meningioma features, thus establishing these cell systems as disease-relevant models for studying NF2 tumorigenesis.

Soft-tissue perineurioma in a 20-year-old patient with neurofibromatosis type 1 (NF1): report of a case and review of the literature

BACKGROUND

Perineurioma is a rare benign soft-tissue tumor composed of cells showing differentiation toward the perineurial cells of the nerve sheath. Although mutations in the neurofibromatosis 2 (NF2) gene have been documented in this tumor, there is no known association between perineuriomas and type 1 or 2 NF.

METHODS

This is the first report of a case of soft-tissue perineurioma occurring in a patient with NF1.

RESULTS

Histopathologic examination revealed a 2.0-cm well-circumscribed, spindle-cell neoplasm with slender, elongated, bipolar, wavy cytoplasmic processes and wavy, elongated nuclei in a hyalinized stroma with focal myxoid areas. The architecture was composed predominantly of short fascicles with areas exhibiting a storiform pattern. Immunohistochemistry showed positive labeling for epithelial membrane antigen (EMA) but no staining for S-100 and smooth muscle actin (SMA).

CONCLUSION

This case illustrates that perineurioma can occur in association with NF1. Perineuriomas can be confused with other spindle-cell neoplasms, and relevant features and immunohistochemistry of these lesions are outlined. The patient has not had a recurrence with limited follow-up.