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PubMed2001

The clinical and diagnostic implications of mosaicism in the neurofibromatoses.

Neurofibromatosis type 1 and type 2 both occur in mosaic forms. Mosaicism results from somatic mutations. Early somatic mutations cause generalized disease, clinically indistinguishable from nonmosaic forms. Later somatic mutation gives rise to localized disease often described as segmental. In individuals with mosaic or localized manifestations of neurofibromatosis type 1 (segmental neurofibromatosis type 1), disease features are limited to the affected area, which varies from a narrow strip to one quadrant and occasionally to one half of the body. Distribution is usually unilateral but can be bilateral, either in a symmetric or asymmetrical arrangement. Patients with localized neurofibromatosis type 2 have disease-related tumors localized to one part of the nervous system; for example a unilateral vestibular schwannoma with ipsilateral meningiomas or multiple schwannomas in one part of the peripheral nervous system. The recognition of mosaic phenotypes is important. Individuals with the mosaic form, even with a generalized phenotype, are less likely to have severe disease. They also have lower offspring recurrence risk than individuals with the nonmosaic form. The mosaic forms of neurofibromatosis provide a good example of the effects of somatic mutation. It is increasingly recognized that mild and unusual forms of many dominantly inherited disorders are caused by the same mechanism.

Humans↗
PubMedDate not supplied

Neurofibromatoses.

Explore the source record for details and available documents.

Humans↗
PubMed1998

[Neurofibromatosis].

Neurofibromatoses regroup at least two different autosomal dominant disorders, neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). NF1 gene and NF2 genes have been respectively localized on chromosomes 17 and 22. NF1 represents 95% of neurofibromatoses cases. Its incidence is 1 for 3,500 newborns, its prevalence 1 for 4,500. NF1 is characterized by its cutaneous manifestations, café au lait spots, lentigines and neurofibromas. NF2 incidence is 1 for 33,000-40,000 newborns. NF2 is characterized by bilateral vestibular schwannomas (former acoustic neurinomas) and other tumors of the central nervous system. The hallmark of schwannomatosis (neurilemmomatosis) is multiple cutaneous or subcutaneous schwannomas without vestibular schwannomas. Different neurofibromatoses are characterized by different prognosis, complications, and genetic counseling. Multidisciplinary centers with trained physicians are ideal structures for management of neurofibromatoses patients.

Diagnosis, Differential↗
PubMed1998

[Recklinghausen neurofibromatosis. Report of a case].

Neurofibromatoses are genetic disorders of the nervous system that primarily affect the development and growth of neural cell tissues. These disorders produce other abnormalities such as skin changes and bone deformities. Neurofibromatoses occur in both sexes and in all races and ethnic groups. Scientists have classified these disorders as neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). Other types of neurofibromatoses may exist, but are not yet identified. Nearly 50% of the cases shows a well definited familiarity for the disease, according to an autosomal dominant transmission, while the other 50% of patients shows a negative history of familiarity, according to a new chromosomal mutation interesting the same autosomal genes of the dominant transmission. Oral localization is more rare showing an incidence ranging from 4 to 7% in most series of different authors. The most frequent involvement site in oral neurofibromatosis is the tongue, followed by the oral mucosa and floor of the mouth; palate and maxillary-mandibular bones are a rare localization of the disease. In the present, the clinical, radiological, histopathological and therapeutical aspects of a clinical case of neurofibromatosis, presenting as mandibular tumor, are examined. The clinical case reported, a 37 year old man, was essentially characterized by a positive family history for the disease, a neurofibroma of the oral mucosa.

Adult↗
PubMed2001

Neurofibromatosis: clinical presentations and anaesthetic implications.

The neurofibromatoses are autosomal dominant diseases that have widespread effects on ectodermal and mesodermal tissue. The commonest member of the group is neurofibromatosis type 1 (NF1) which varies in severity but which can affect all physiological systems. Neurofibromas are the characteristic lesions of the condition and not only occur in the neuraxis but may also be found in the oropharnyx and larynx; these may produce difficulties with laryngoscopy and tracheal intubation. Pulmonary pathology includes pulmonary fibrosis and cystic lung disease. The cardiovascular manifestations of NF1 include hypertension, which may be associated with phaeochromocytoma or renal artery stenosis. Neurofibromas may also affect the gastrointestinal tract and carcinoid tumours may be found in the duodenum. This review documents the aetiology and clinical manifestations of the neurofibromatoses and discusses their relevance to the anaesthetist.

Anesthesia↗
PubMed2006

[Difficulties of the management of head and neck neurofibromatosis].

INTRODUCTION: Neurofibromatoses represent a group of 7 diseases having the same cutaneous signs due to a common embryologic origin. The types 1 and 2 are the most frequent and the most studied. Neurofibromatosis type 1 (NF1) or Von Recklinghausen's neurofibromatosis is an autosomal dominantly inherited disease, whose prevalence is 1/4500. The cranio-orbitotemporal lesions exist in 1 to 10% of the cases. Neurofibromatosis type 2 (NF2) is also an autosomal dominantly inherited disease, but is ten times less frequent than the NF1 and is characterized by bilateral vestibular schwannomas (former acoustic neurinomas). The purpose of this work was to detail the clinical features, highlighting the diagnostic and therapeutic difficulties. MATERIAL AND METHODS: Nine patients managed between 1990 and 2005 were reviewed retrospectively. Eight patients were found carrier of NF1 and one patient carrier of NF2 according to the diagnostic criteria of the 1988's National Institute of Health consensus. RESULTS: Five women and four men were managed; patient age varied between 13 and 62 years and the mean age was 26 years. Surgical resection of the tumor was carried out among 8 patients with bone reconstruction of the orbit on 3 patients and cutaneous expansion on one other. The results are difficult to appreciate especially that the surgery was iterative. However, all our patients were satisfied with the result and we noted recurrence in a patient presenting a retro-auricular tumor, which filled the external auditory canal requiring a further surgery. The patient having NF2 was treated by neurosurgery and showed a good result. DISCUSSION: The NF1 manifestations are extremely variable. Facial neurofibromatoses are difficult to control given the presence of soft tissues infiltration and the associated osseous dysplasia. The results are modest and recurrence is frequent. Cancer risks and the disease's completely unpredictable evolution urge a regular and multidisciplinary patient follow-up.

Adolescent↗
PubMed2002

Neurofibroma and schwannoma.

PURPOSE OF REVIEW: Neurofibromas and schwannomas are benign peripheral nerve sheath tumours that occur as isolated sporadic lesions, but have their major clinical impact on the neurocutaneous diseases neurofibromatosis 1 and neurofibromatosis 2. The gene products neurofibromin and merlin (schwannomin), respectively, are thought to act as tumour suppressors. The aim of this review is to document recent advances in our understanding of the clinical characteristics and pathogenesis of neurofibromas and schwannomas in the neurofibromatoses. RECENT FINDINGS: Animal models have shed light on the pathogenesis of neurofibromas confirming that the Schwann cell initiates neurofibroma formation. New data suggest that individuals with neurofibromatosis 1 have a 10% lifetime risk of developing malignant peripheral nerve sheath tumours. Positron emission tomography with the glucose analogue 18-fluorodeoxyglucose might be helpful in the diagnosis of malignant peripheral nerve sheath tumours. Such tumours associated with neurofibromatosis 1 show a loss of neurofibromatosis 1 expression and high levels of Ras, but malignant transformation requires additional genetic events that inactivate key cell cycle regulators. Neurofibromatosis 2-associated vestibular schwannomas have variable growth rates that tend to decline with age. Early microsurgery for small tumours results in optimal preservation of hearing and facial nerve function. Currently, radiosurgery for these lesions produces similar results. Systematic follow-up of both groups will determine the best treatment method. Merlin's function as a tumour suppressor has not been elucidated. The control of cell cycle progression and abnormal intracellular and extracellular signalling could all play a part. SUMMARY: Molecular advances will allow a biological approach to targeted therapies for neurofibromas, malignant peripheral nerve sheath tumours and schwannomas. Knowledge of the pathogenesis of these tumours will have implications for our understanding of the neurofibromatoses and of the formation of sporadic tumours.

Animals↗
PubMed1983

Surgical treatment of vertebral deformities in neurofibromatosis.

Vertebral deformity in neurofibromatosis can present in two basic forms which determine the prognosis and treatment. In the first form, which is rare, there are no gross dystrophic changes, while in the second, which is the more common, such changes are widespread. Neurofibromatosic scoliosis where there are no signs of bone dystrophy poses no particular therapeutic problems. However, the surgical treatment of the dystrophic form is much more complex and the results far more uncertain. There is a high incidence of pseudarthrosis following posterior arthrodesis and fixation with Harrington rods, and this has shown the need for combined posterior and anterior arthrodesis in all cases of neurofibromatosic kyphoscoliosis. Furthermore, posterior arthrodesis alone does not provide protection against future relapse even when kyphosis is initially absent. Delayed kyphosis, due to subsidence of the vertebral bodies, frequently appears after six months and necessitates a second operation to reinforce the posterior arthrodesis. However, a greater guarantee of stability can be achieved simply by performing combined anterior and posterior arthrodesis at the outset.

Adolescent↗
PubMed1996

[Natural evolution of neurocutaneous syndrome in adults].

Neurofibromatoses (NF1 and NF2) are genetic diseases with an extremely wide range of manifestations, particularly NF1. In order to gain insight into their prognosis, we have conducted a follow-up study of 100 patients with neurofibromatoses, 89 NF1 patients and 11 NF2 patients all of them presenting neurological manifestations. Four deaths occurred in the NF1 group (3 neurofibrosarcomas) and two in the NF2 group (after neurosurgery). We describe a series of NF1 brainstem tumors as being pilocytic astrocytomas, much less aggressive than non-NF1 brainstem tumors but more symptomatic than brainstem UBOs ('unidentified bright objects') in NF1. The series of optic nerve tumors also demonstrate the poor and non-progressive evolution of tumors with the same histopatological estructure. Hydrocephalus related to aqueductal stenosis is a frequent and tratable manifestation in NF1 patients. Data are presented which suggest that a severe form of NF2 is much more frequent than a mild form but it is rule that number and progressivity of tumors render the prognosis always severe in NF2 patients. A long term follow-up study has been carried among 20 patients with tuberous sclerosis: patients who presented seizures before the age of 5 years have mental retardation in spite of disappearing, often spontaneously, the seizures. The initial symptoms in Von Hippel-Lindau patients depend often on the hemangioblastoma of the spinal cord and a strict control is proposed for patients with risk of suffering spinal-cerebello-retino hemangioblastomatosis. Other phakomatoses are also being considered in their general prognosis.

Adolescent↗
PubMed2005

Aneurysm of the popliteal artery in neurofibromatosis.

The neurofibromatoses are a heterogeneous set of genetic disorders having clinical manifestations that involve the skin, the nervous system, or both. In addition, the disease can be confounded by a broad spectrum of complications, such as various kinds of osseous lesion, vascular lesions, aqueduct stenosis, optic glioma, and learning disabilities. Neurofibromatosis results in vascular involvement in approximately 10% of cases. Stenotic lesions predominate, but aneurysms have been documented as well. Rarely noted, however, have been peripheral aneurysms. In this report, we discuss the case of a 66-year-old woman with type 1 neurofibromatosis and a popliteal artery aneurysm who was operated upon because of threatened limb ischemia. Histological findings confirmed neurofibromatous invasion of the vessel wall.

Aged↗
PubMedDate not supplied

Establishing priorities in neurofibromatosis research: a workshop summary.

Progress in understanding the biology of the neurofibromatoses (NF1 and NF2) offers hope for the development of new, effective methods of treatment. In May 2000, the National Institute of Neurological Disorders and Stroke (NINDS) hosted a workshop that included leading researchers and clinicians from the NF community. The goal of the meeting was to assess current knowledge and identify priorities for future research. Needs identified included the development of better animal models, further study of the function of the NF1 and NF2 genes, and investigation of the role of modifier genes. The participants agreed that it will also be important to define further the natural history of NF1 and NF2 and to develop an infrastructure to support clinical trials. They also discussed the possible creation of research consortia and NF centers to promote the integration of basic and clinical research.

Animals↗
PubMed1992

Aspects in neurofibromatosis from the viewpoint of dermatology.

The neurofibromatoses are a heterogenous set of conditions having clinical manifestations such as skin, nervous system, bone and eye disorders. The clinical pictures of the patients will obviously differ, and there is considerable variation of manifestations even within a family. During the last twenty-five years, one thousand and two hundred patients with neurofibromatosis were personally examined. Almost all our patients had classical von Recklinghausen disease. But in addition to these cases, there are 28 cases of NF-2 and 10 patients which we call multiple neurilemmomatosis. Also, there are related groups of patients with conditions which were not neurofibromatosis, such as 40 cases of localized multiple neurofibromas and 61 cases of localized café-au-lait spots. The features of neurofibromatosis in Japan are not different, compared with foreign countries, except increased pigmentation is more common. In addition to café-au-lait spots, some 20% of Japanese neurofibromatosis patients have pigmentary conditions which I termed hairy fuscoceruleus spots. These spots are blue-brown in colour, and one can see coarse hairs in them. Our recent study indicates that the patients with neurilemmomatosis have loss of heterozygosity of chromosome 22, the same position as the site of patients with NF-2. Neurilemmomatosis may be classified as an NF-2 without acoustic tumors.

Adolescent↗
PubMed2005

Malignant transformation and new primary tumours after therapeutic radiation for benign disease: substantial risks in certain tumour prone syndromes.

In recent years the use of radiation treatment for benign tumours has increased with the advent of stereotactic delivery and, in particular, single high dose gamma knife therapy. This has been particularly true for benign CNS (central nervous system) tumours such as vestibular schwannoma, meningioma, pituitary adenoma, and haemangioblastoma. While short term follow up in patients with isolated tumours suggests this treatment is safe, there are particular concerns regarding its use in childhood and in tumour predisposing syndromes. We have reviewed the use of radiation treatment in these contexts with particular regard to malignant transformation and new tumour induction. This review indicates that much more caution is warranted regarding the use of radiation treatment for benign tumours in childhood and in tumour prone conditions such as the neurofibromatoses.

Basal Cell Nevus Syndrome↗
PubMed1992

Constitutional ring chromosomes and tumour suppressor genes.

The types of malignancy reported in carriers of constitutional ring chromosomes r(11), r(13), and r(22) are concordant with the chromosomal assignment of tumour suppressor loci associated with Wilms' tumour, retinoblastoma, and meningioma. It is suggested that the somatic instability of ring chromosomes may play a role in this association and that constitutional ring chromosomes may be a source for mapping of tumour suppressor loci with the potential for covering most or all of the human genome. The hypothesis predicts the presence of a locus on chromosome 10 associated with follicular carcinoma of the thyroid, in line with previous cytogenetic findings of rearrangements involving chromosome 10 in thyroid tumours, and a locus on chromosome 22 associated with testicular cancer. Development of neurofibromatoses (NF) that do not fulfil the clinical criteria of neurofibromatosis type 2 (NF2) in carriers with r(22) suggests either the presence of an additional NF locus on chromosome 22 or that ring chromosome mediated predisposition to somatic mutation of a specific tumour suppressor may be associated with atypical development of features usually associated with germline mutations.

Adenocarcinoma↗
PubMed1995

-Coexistence of neural proliferations with early epithelial neoplasias and benign ectopias of the uterine cervix-.

OBJECTIVE: The study wanted to test the hypothesis that stromal systems can influence the development of the epithelium. METHOD: The stroma of specimens obtained by conizations of the cervix was histologically investigated. RESULTS: Neural proliferations such as neuromas, neurofibromas and vascular neurofibromatoses were found. They were common in the presence of epithelial lesions. CONCLUSION: Thus, the frequency of neural proliferations correlated with the nature of the epithelial abnormality. This association argues against the conventional concept that the growth of cervical intraepithelial neoplasias is absolutely autonomous.

Biopsy↗
PubMed2006

Neurofibromatosis--review of the literature and case report.

Neurofibromatoses are genetic disorders of the nervous system that primarily affect the development and growth of neural (nerve) cell tissues. These disorders cause tumors to grow on nerves, and produce other abnormalities such as skin changes and bone deformities. Although many affected persons inherit the disorder, between 30 and 50 percent of new cases arise spontaneously through mutation in the individual's genes. We report on seven cases of type 1 neurofibromatosis (NF1) diagnosed from 2001 to 2006 at our Department. There were four female and three male patients, mean age 46.1 and 49 years, respectively. All patients showed neurofibromas accompanied by fibromas, café au lait spots, cases showed five axillary freckling (lentigines) and one case showed five plexiform neurofibromas and pruritus belonging to NF1 category. All patients had affected first degree relatives. Systemic findings were rare and included optic glioma in one case and Lisch hamartoma nodules in three cases. In all cases, the diagnosis was established according to the National Institutes of Health criteria, including at least two of the diagnostic criteria for NF1 diagnosis. None of our cases had malignancies or gastrointestinal tract involvement.

Female↗
PubMed1994

Head and neck manifestations of neurofibromatosis.

The neurofibromatoses are one of four neurocutaneous syndromes inherited in an autosomal dominant pattern and characterized by generalized cutaneous neurofibromas. They are often associated with central and peripheral nervous system tumors, café-au-lait spots, skeletal abnormalities, and a myriad of associated abnormalities. Neurofibromatosis 1 (NF-1) and neurofibromatosis 2 (NF-2) are clinically and genetically distinct diseases. The diseased gene for NF-1 is the long arm of chromosome 17 and for NF-2 it is the long arm of chromosome 22. Universal signs for NF-1 include Lisch nodules (melanocytic iris hamartomas), optic nerve gliomas, and axillary freckling. The hallmark of NF-2 is bilateral acoustic neuromas. The incidence of head and neck lesions in NF-1 and NF-2 is approximately 37% with a 3.5% malignant transformation rate. A team approach is essential for management of both NF-1 and NF-2 due to multiple organ system involvement.

Head and Neck Neoplasms↗