Neurofibromatosis tipos 1 y 2 / Neurofibromatosis type 1 and 2

La neurofibromatosis (NF) comprende un grupo de enfermedades genéticas de herencia autosómica dominante, que se clasifican de la siguiente manera: neurofibromatosis tipo 1 (NF1), neurofibromatosis tipo 2 (NF2) y schwannomatosis (también conocida como neurofibromatosis tipo 3). Esta última es una enfermedad muy infrecuente, con una prevalencia aproximada de 1/126 000 personas, por lo que solo profundizaremos las dos primeras. La NF1, también conocida como la enfermedad de Von Recklinghausen, es la más frecuente de las tres y afecta principalmente la piel y el sistema nervioso periférico. Se caracteriza por la presencia de máculas "café con leche", pecas axilares o inguinales, nódulos de Lisch (hamartomas en el iris) y neurofibromas (tumores de la vaina de nervios periféricos). Otras manifestaciones menos frecuentes, aunque de mayor gravedad, incluyen gliomas del nervio óptico, meningiomas, neurofibromas malignos, escoliosis y displasia de la tibia. Su diagnóstico se suele realizar al nacimiento o durante los primeros años de vida, y se estima que un 50% de quienes la padecen presenta dificultades cognitivas. No hay datos concluyentes sobre la mortalidad en los pacientes con NF1, aunque se sabe que la expectativa de vida es menor que en la población general. La NF2 tiene una prevalencia considerablemente menor que la NF1 y su inicio es más tardío, afectando principalmente a adultos jóvenes. La presentación clínica típica se caracteriza por acúfenos, hipoacusia y ataxia en contexto de la presencia de schwannomas vestibulares bilaterales. Otros hallazgos menos frecuentes incluyen schwannomas de nervios periféricos, meningiomas, ependimomas o astrocitomas. La esperanza de vida es de unos 36 años, con una supervivencia media desde el momento del diagnóstico de 15 años. (AU)

Neurofibromatosis (NF) includes a group of genetic diseases with an autosomal-dominant inheritance pattern, and they are classified as follows: Neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and Schwannomatosis (also known as neurofibromatosis type 3). This last one is a very rare disease, with an approximate prevalence of 1/126000, so we will only deepen in the first two. NF1, also known as von Recklinghausen disease, is the most frequent, and mainly affects the skin and peripheral nervous system. Its typical manifestations are the presence of café-au-lait macules, axillary or inguinal freckles, Lisch nodules (hamartomas in the iris) and neurofibromas (peripheral nerve sheath tumors). Less frequent manifestations, although more serious, include optic nerve gliomas, meningiomas, malignant neurofibromas, scoliosis and tibial dysplasia. The diagnosis is usually made at birth or during the first years of life, and approximately 50% of patients present cognitive difficulties. There is no conclusive data on mortality in patients with NF1, although it is known that life expectancy is lower than in general population. NF2 has a considerably lower prevalence than NF1, and its onset is later in life, mainly affecting young adults. Its typical clinical presentation is characterized by tinnitus, hearing loss and ataxia in the context in the presence of bilateral vestibular schwannomas. Less frequent findings include peripheral nerve schwannomas, meningiomas, ependymomas or astrocytomas. Life expectancy is about 36 years old, with a median survival from the moment of diagnosis of 15 years. (AU)

Sporadic Schwannomatosis: A Systematic Review Following the 2005 Consensus Statement.

AIMS: To identify the frequency of reports of sporadic schwannomatosis, the types of patients affected, and the nerves affected. PATIENTS AND METHODS: We identified all case reports and case series that reported on patients with sporadic schwannomatosis according to established criteria. RESULTS: The initial search yielded 1,597 studies, of which 15 were included. A total of 38 of 55 individuals met the inclusion criteria. The mean age of the patients was 48 years; 41% were male. Thirty-three patients had peripheral nerve tumors, and 17 had spinal tumors. Twelve had tumors in both locations. Tumor distribution was unilateral in 25 of 30 cases (83.3%) and segmental (limited to one limb or five or fewer contiguous segments of the spine) in 28 of 38 cases (73.7%). CONCLUSION: This systematic review quantified the number of individuals who meet the criteria for sporadic schwannomatosis and better described this population to facilitate the classification of neurofibromatosis in regard to the 2005 consensus statement. Unilateral or segmental distribution of nerve tumors are key aspects when dealing with multiple noncutaneous schwannomas without involvement of the vestibular nerve.

Neurofibromatosis and the role of the specialist adviser.

Neurofibromatosis (NF) is a genetic condition that mainly involves the nervous system. There are two types: NF1 affects about one in 2,500 of the population worldwide and NF2 affects one in 35,000. Both types result in complex health problems for patients and can pose significant challenges for all those involved in their management. Established in 1981, The Neuro Foundation is a patient-focused charity that funds a network of specialist advisers who work in partnership with the NHS to offer support and advice for families affected by NF and the professionals who care for them. With a significant level of autonomy, the specialist adviser role is flexible in matching the needs of those affected while working cooperatively alongside the national specialist services for NF1 and NF2.

Methylation-based classification of benign and malignant peripheral nerve sheath tumors.

The vast majority of peripheral nerve sheath tumors derive from the Schwann cell lineage and comprise diverse histological entities ranging from benign schwannomas and neurofibromas to high-grade malignant peripheral nerve sheath tumors (MPNST), each with several variants. There is increasing evidence for methylation profiling being able to delineate biologically relevant tumor groups even within the same cellular lineage. Therefore, we used DNA methylation arrays for methylome- and chromosomal profile-based characterization of 171 peripheral nerve sheath tumors. We analyzed 28 conventional high-grade MPNST, three malignant Triton tumors, six low-grade MPNST, four epithelioid MPNST, 33 neurofibromas (15 dermal, 8 intraneural, 10 plexiform), six atypical neurofibromas, 43 schwannomas (including 5 NF2 and 5 schwannomatosis associated cases), 11 cellular schwannomas, 10 melanotic schwannomas, 7 neurofibroma/schwannoma hybrid tumors, 10 nerve sheath myxomas and 10 ganglioneuromas. Schwannomas formed different epigenomic subgroups including a vestibular schwannoma subgroup. Cellular schwannomas were not distinct from conventional schwannomas. Nerve sheath myxomas and neurofibroma/schwannoma hybrid tumors were most similar to schwannomas. Dermal, intraneural and plexiform neurofibromas as well as ganglioneuromas all showed distinct methylation profiles. Atypical neurofibromas and low-grade MPNST were indistinguishable with a common methylation profile and frequent losses of CDKN2A. Epigenomic analysis finds two groups of conventional high-grade MPNST sharing a frequent loss of neurofibromin. The larger of the two groups shows an additional loss of trimethylation of histone H3 at lysine 27 (H3K27me3). The smaller one retains H3K27me3 and is found in spinal locations. Sporadic MPNST with retained neurofibromin expression did not form an epigenetic group and most cases could be reclassified as cellular schwannomas or soft tissue sarcomas. Widespread immunohistochemical loss of H3K27me3 was exclusively seen in MPNST of the main methylation cluster, which defines it as an additional useful marker for the differentiation of cellular schwannoma and MPNST.

Neurofibromatosis of the head and neck: classification and surgical management.

BACKGROUND: Neurofibromatosis is common and presents with variable penetrance and manifestations in one in 2500 to one in 3000 live births. The management of these patients is often multidisciplinary because of the complexity of the disease. Plastic surgeons are frequently involved in the surgical management of patients with head and neck involvement. METHODS: A 20-year retrospective review of patients treated surgically for head and neck neurofibroma was performed. Patients were identified according to International Classification of Diseases, Ninth Revision codes for neurofibromatosis and from the senior author's database. RESULTS: A total of 59 patients with head and neck neurofibroma were identified. These patients were categorized into five distinct, but not exclusive, categories to assist with diagnosis and surgical management. These categories included plexiform, cranioorbital, facial, neck, and parotid/auricular neurofibromatosis. CONCLUSIONS: A surgical classification system and clinical characteristics of head and neck neurofibromatosis is presented to assist practitioners with diagnosis and surgical management of this complex disease. The surgical management of the cranioorbital type is discussed in detail in 24 patients. The importance and safety of facial nerve dissection and preservation using intraoperative nerve monitoring were validated in 16 dissections in 15 patients. Massive involvement of the neck extending from the skull base to the mediastinum, frequently considered inoperable, has been safely resected by the use of access osteotomies of the clavicle and sternum, muscle takedown, and brachial plexus dissection and preservation using intraoperative nerve monitoring. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Características del neurofibroma plexiforme en pacientes con neurofibromatosis tipo 1, Pinar del Río / Characteristics of plexiform neurofibroma in patients suffering from Type-1 Neurofibromatosis, Pinar del Rio

El neurofibroma plexiforme es un tumor complejo, que involucra varios tejidos. Llevan a una distorsión masiva del lugar donde se encuentran, originando problemas estéticos y médicos. Con este trabajo se pretende conocer la frecuencia de los neurofibromas plexiformes, en los pacientes con neurofibromatosis tipo 1, la localización, sexo y otras características clínico-genéticas y diseñar un protocolo de diagnóstico y tratamiento de los neurofibromas plexiformes en la provincia. Se realizó un estudio descriptivo, transversal a pacientes, con neurofibroma plexiforme. Del total de pacientes, 34 presentaron neurofibroma plexiforme, predominando el sexo femenino. La mayoría de los neurofibromas plexiformes se localizaron en extremidades, tronco y cráneo-cara. La hiperpigmentación y la hipertricosis resultaron los signos clínicos más frecuentes. Se diseñó un protocolo para el diagnóstico y tratamiento de los afectados(AU)

Plexiform neurofibroma is a complex tumor involving several tissues, this tumor provokes a massive distortion of the region where it is located leading to esthetical and medical problems. This work was aimed at knowing the frequency of plexiform neurofibromas in patients suffering from Type-1 neurofibromatosis, location, prevalence of sex and other clinical-genetic characteristics to design a protocol of diagnosis and treatment of plexiform neurofibromas in Pinar del Rio province. A descriptive, cross-sectional study was carried out in patients suffering from plexiform neurofibroma. Out of the total of patients, 34 presented plexiform neurofibroma, female sex prevailed. The majority of plexiform neurofibromas were located in limbs, torso and skull-face. The hyperpigmentation and the hypertrichosis were the most frequent clinical signs. A protocol was designed to accomplish the diagnosis and treatment of the patients affected(AU)

Reporte de familias con neurofibromatosis y otras enfermedades genéticas / Reports of families suffering from neurofibromatosis and other genetic disorders

La neurofibromatosis tipo 1, es una enfermedad genética que primariamente afecta el desarrollo y crecimiento celular del sistema nervioso, clínicamente se caracteriza por máculas café con leche, neurofibromas, pecas en regiones no expuestas al sol, nódulos de Lisch, lesiones óseas y glioma óptico. En el presente trabajo se describen dos familias, en las cuales algunos individuos padecen esta enfermedad y otros miembros de la misma familia muestran una diferente enfermedad genética. La coexistencia intrafamiliar de dos enfermedades genéticas diferentes es muy poco frecuente, es por ello, que se decide realizar la revisión y publicación científica sobre el tema...(AU)

Neurofibromatosis type-1 is a genetic condition that affects the development and cellular growth of the nervous system, which is clinically characterized by multiple café-au-lait spots, neurofibromas, freckles in non-sun exposed regions, Lisch nodules, osseous lesions and optic glioma. The present paper describes two families, having some individuals suffering from this condition and other members of the same family who present a different genetic condition. The intrafamilial coexistence of two different genetic conditions is very rare, that is why a literature review and a scientific research about the topic were carried out...(AU)

Short mandible, maxilla and cranial base are common in patients with neurofibromatosis 1.

Neurofibromatosis type 1 (NF1) is an autosomal-dominant neuro-cutaneous-skeletal syndrome. Neurofibromatosis type 1 is one of the Rasopathies, and at the cellular level NF1 results in a hyperactive Ras pathway. In the current investigation, our aim was to study lateral skull X-rays (cephalograms) to assess NF1-related craniofacial morphology. A total of 85 Finnish patients with NF1, including four patients with plexiform neurofibroma of the 5th cranial nerve, and their age- and gender-matched controls, were enrolled in the study. The results showed that patients with NF1 typically had a short mandible, maxilla, and cranial base compared with healthy controls, irrespective of age, but the results were statistically significant only in adults. The length of the mandible, the maxilla and the cranial base correlated with the height of patients under 19 yr of age, but this correlation was absent in adult patients. Thus, a tall adult patient with NF1 may have short jaws and a short cranial base. In conclusion, the NF1 gene apparently influences the growth of craniofacial bones, thus contributing to the craniofacial morphology in NF1.

Orbitotemporal neurofibromatosis: classification and treatment.

PURPOSE: To review the clinical findings in orbitotemporal neurofibromatosis and discuss treatment options. Clinical features, histopathologic characteristics, and treatment options are reviewed. METHODS: A Medline literature search from 1966 to 2004 was performed, using the key words: orbitotemporal neurofibromatosis, orbitopalpebral neurofibromatosis, orbitofacial neurofibromatosis, cranio-orbital neurofibromatosis, and cranio-orbital-temporal neurofibromatosis, and the pertinent literature was reviewed. Additionally, our experience with two patients is reported. The surgical procedures are discussed. CONCLUSION: The management of orbitotemporal neurofibromatosis is challenging. The planned surgical approach and extent of resection depend on the severity of the orbital soft tissue and bony involvement and on the visual potential. Ultimately, orbital exenteration may be needed for rehabilitation and cosmesis.

Intestinal neurofibromatosis is a subtype of familial GIST and results from a dominant activating mutation in PDGFRA.

BACKGROUND & AIMS: Intestinal neurofibromatosis (Online Mendelian inheritance in Man database number 162220) is an alternate form of neurofibromatosis. Patients present with neurofibromas limited to the intestine in the absence of any other typical features of NF1 and NF2. At present, the molecular basis of intestinal neurofibromatosis remains elusive. The aim of the present study was to find the gene responsible for intestinal neurofibromatosis and to characterize functionally the mutation. METHODS: Three candidate genes (NF1, KIT, and PDGFRA) were screened for mutations in 3 sisters diagnosed with intestinal neurofibromatosis. Five tumors were available for pathologic examination. Activation (phosphorylation) of PDGFRalpha was subsequently tested by Western blot analysis on a transfected 293T and Ba/F3 cell line. RESULTS: We found an inherited mutation (Y555C) in the juxtamembrane domain of PDGFRA in the affected individuals. The Y555C mutation leads to autophosphorylation and thus activation of PDGFRalpha. These observations confirm that PDGFRalpha(Y555C) is an oncogenic kinase. The clinical phenotype in the reported family resembles the syndrome of familial gastrointestinal stromal tumors (familial GIST). Somatic activating mutations in KIT and PDGFRA are frequent in sporadic GISTs, and mutations in both genes have also been described in familial GISTs. The tumors in the reported family are morphologically identical to intestinal neurofibromas, but, immunohistochemically, they do not express S100 or any of the known GIST markers. CONCLUSIONS: The inherited PDGFRA mutation in the reported family shows that intestinal neurofibromatosis is allelic to familial GIST caused by PDGRA mutations. We therefore propose that these tumors be classified as familial KIT-negative gastrointestinal stromal tumors.

Lack of evidence for an association between neurofibromatosis and pulmonary fibrosis.

STUDY OBJECTIVES: To reassess the association between neurofibromatosis and pulmonary fibrosis. DESIGN: Retrospective single-center study with analysis of patients' chest radiographs, CT scans, and medical records. SETTING: Tertiary care, referral medical center. PATIENTS: One hundred fifty-six adult patients with neurofibromatosis seen over a 6-year period between 1997 and 2002. RESULTS: A review of chest radiographs revealed abnormal findings in 70 patients (44.9%). The most common radiographic abnormalities were extrapulmonary nodules or masses seen in 22 patients (14.1%), followed by skeletal abnormalities in 16 patients (10.3%). Bilateral interstitial infiltrates were noted in only three patients (1.9%), all of whom had potential causes other than neurofibromatosis for their lung infiltrates, including smoking-related interstitial lung disease, rheumatoid lung disease, recurrent pneumonias, and a history of ARDS. CT scans were available in two of these patients and revealed nonspecific patterns of abnormalities with no honeycombing. Six patients had bullae or cystic airspaces demonstrated on chest radiography or CT scan; all of these findings occurred in the context of smoking-related emphysema. Combined together, bilateral interstitial lung infiltrates or cystic airspaces were demonstrated in five patients (3.2%) by chest radiography, and in eight patients (5.1%) by chest radiography or CT scanning; one patient had both findings on the CT scan. CONCLUSIONS: We found little evidence to support an association between neurofibromatosis and pulmonary fibrosis or any other form of parenchymal lung disease. Interstitial lung disease and bullae described in association with neurofibromatosis in previous reports may have, in part, represented smoking-induced manifestations.

Segmental neurofibromatosis.

A 74-year-old man presented with skin-colored nodules in his left antecubital fossa. The lesions had been present for 35 years and were asymptomatic. Nodules elsewhere on the body, cafe-au-lait spots, axillary freckling, and Lisch nodules were absent. No family members had similar nodules. A diagnosis of segmental neurofibromatosis was made, and a biopsy specimen of a nodule showed a neurofibroma. As the patient had no complications of neurofibromatosis 1, no treatment was needed.

Familial schwannomatosis: exclusion of the NF2 locus as the germline event.

BACKGROUND: Schwannomatosis is a recently recognized disorder, defined as multiple pathologically proven schwannomas without vestibular tumors diagnostic of neurofibromatosis 2 (NF2). Some investigators have questioned whether schwannomatosis is merely an attenuated form of NF2. METHODS: The authors identified eight families in which a proband met their diagnostic criteria for schwannomatosis. Archived and prospectively acquired tumor specimens were studied by mutational analysis at the NF2 locus, loss of heterozygosity analysis along chromosome 22, and fluorescent in situ hybridization analysis of NF2 and the more centromeric probe BCR. Linkage analysis could be performed in six of eight families. RESULTS: Clinical characterization of these kindreds showed that no affected family member harbored a vestibular tumor. Molecular analysis of 28 tumor specimens from 17 affected individuals in these kindreds revealed a pattern of somatic NF2 inactivation incompatible with our current understanding of NF2 as an inherited tumor suppressor gene syndrome. Linkage analysis excluded the NF2 locus in two kindreds, and showed a maximum lod score of 6.60 near the more centromeric marker D22S1174. CONCLUSIONS: Schwannomatosis shows clinical and molecular differences from NF2 and should be considered a third major form of neurofibromatosis. Further work is needed to identify the inherited genetic element responsible for familial schwannomatosis.

Neurofibromatosis segmentaria / Segmentary neurofibromatosis

Comunicamos un caso de neurofibromatosis segmentaria en un paciente de sexo masculino de 65 años de edad. Los neurofibromas se ubicaban en la región escapular derecha. La evolución de los mismos es de cinco años. No fueron constatadas manchas café con leche ni otra alteración característica de la neurofibromatosis tipo 1. En nuestro caso el principal diagnóstico diferencial fue con acrocordones-nevos fibromatosos. Efectuamos una breve revisión de la literatura (AU)

[Neurofibromatoses. Types, classification and diagnostic criteria]. / Nevrofibromatozi. Vidove, klasifikatsiia i diagnostichni kriterii.

According to the worldwide-accepted classification of the neurofibromatoses only neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2) are well defined. Other described forms of neurofibromatosis are rare. The aim of this paper is to review the contemporary classification and diagnostic criteria of the different types of neurofibromatoses.

[Multiple intracranial and intraspinal meningiomas in the neurocristopathy (phacomatosis) type of neurofibromatosis]. / Mnohopocetné intrakraniálne a intraspinálne meningiómy v rámci neurokristopatie (fakomatózy) typu neurofibromatózy.

Presentation of a case of a "central type" neurofibromatosis in a 56-year old woman, clinically diagnosed erroneously as multiple sclerosis with a 20 years long course. Disturbances of hearing, walking, sight, sensitivity, incontinentia, intracranial hypertension and headache represented the main symptoms. More than 120 intracranial and tens of intraspinal meningiomas represented the leading postmortem finding. In a lesser frequency spinal plexiform neurofibromas and schwannomas were also found. The death was attributed to aspiration purulent bronchopneumonia. Various types of meningioma were seen microscopically, including secretory type and a type with amyloid. Immunostaining was positive with S-100 protein and EMA. Negative expression was found with vimentin, CEA, smooth muscle actin, estrogen and progesterone receptors, amyloid A and cytokeratins. With regard to the presence or absence of key morphological features the presented case was placed according to Sobol et al. (29) into the seventh category of neurofibromatosis (NF7).

Neurofibromatosis. Nosological considerations.

The neurofibromatosis (NF) represent a set of conditions having different clinical manifestations, prognosis and inheritance. It has been presented--on clinical grounds--seven types of NF, but for only two of these National Institute of Health Consensus Development Conference (NIHCDC) advent a set of diagnostic criteria. The genes responsible for NF1 and NF2 were mapped to the long arm of chromosome 17 (17q11.2) and respectively 22 (22q11.2), and their protein product (neurofibromin and respectively merlin or schwanomin) was identified. Recent studies are proved that NF1 and NF2 genes act as a tumour suppressor gene. Up to now, only a limited number of mutations in these genes have been characterized but even in these cases the genotype/fenotype correlation has not provided enough information to allow speculation on the etiologic role NF1 or NF2 mutations might play in the variant forms of NF. Further studies are required to elucidate the genes functions and mutation spectrum. This should provide a framework for the molecular classification and diagnosis and the development of new therapy for NF.