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PubMed1990

Plexiform neurofibromatosis of the liver and mesentery in a child.

Plexiform neurofibromatosis of the liver was recognized by needle biopsy of the liver in an 11-yr-old boy who had a 2-yr history of diarrhea, intermittent abdominal pain, failure to gain weight and progressive abdominal distention. Imaging studies demonstrated a large retroperitoneal mass; a laparotomy was performed. At surgery, the mesentery was greatly thickened by neurofibromas, and plexiform neurofibroma extended through the hilum of the liver. Light and electron microscopy demonstrated that in addition to the direct involvement by tumor, neural hyperplasia existed throughout the liver. The most distal ramifications of the portal spaces were filled with Schwann cells, bundles of unmyelinated nerves and perineurium-surrounded nerves containing myelinated and unmyelinated fibers. The ultrastructural findings were consistent with stimulation of proliferation of all the portal neural elements and tumoral tissue. The nontumoral response was more than simple hyperplasia because it appeared to result in fibrotic changes in the most involved areas and active breaching of the limiting plate with destruction of hepatocytes and collagen deposition throughout the liver.

Biopsy, Needle↗
PubMed2006

NF1 mutation rather than individual genetic variability is the main determinant of the NF1-transcriptional profile of mutations affecting splicing.

A significant number of neurofibromatosis type 1 (NF1) mutations result in exon skipping. The majority of these mutations do not occur in the canonical splice sites and can produce different aberrant transcripts whose proportions have not been well studied. It has been hypothesized that differences in the mutation-determined NF1-transcriptional profile could partially explain disease variability among patients bearing the same NF1 splice defect. In order to gain insight into these aspects, we analyzed the proportion of the different transcripts generated by nine NF1-splicing mutations in 30 patients. We assessed the influence of the mutation in the NF1-related transcriptional profiles and investigated the existence of individual differences in a global manner. We analyzed potential differences in tissue-specific transcriptional profiles and evaluated the influence of sample processing and mRNA nonsense-mediated decay (NMD). Small transcriptional differences were found in neurofibromas and neurofibroma-derived Schwann cells (SC) compared to blood. We also detected a higher cell culture-dependent NMD. We observed that mutation per se explains 93.5% of the profile variability among mutations studied. However, despite the importance of mutation in determining the proportion of NF1 transcripts generated, we found certain variability among patients with the same mutation. From our results, it seems that genetic factors influencing RNA processing play a minor role in determining the NF1-transcriptional profile. Nevertheless neurofibromin studies would clarify whether these small differences translate into significant functional changes that could explain the great clinical expressivity observed in the disease or any of the disease-related traits.

Alleles↗
PubMed2006

Atypical and malignant peripheral nerve-sheath tumors of the brachial plexus: report of three cases and review of the literature.

Tumor involvement of the brachial plexus is uncommon. The most common intrinsic neoplasms involving the brachial plexus are benign neurilemmomas and neurofibromas that are usually associated with neurofibromatosis-1 (NF-1). Solitary neurofibromas unassociated with NF-1 are very uncommon. Malignant peripheral nerve-sheath tumors (MPNST) are rare at this site, arising spontaneously or in the context of NF-1. This presentation discusses the clinical presentation, pathology, and management of these tumors, which usually occur in young adults. MPNST are intermediate or high-grade sarcomas with a high risk of local and distant spread. Approximately 50% of MPNST arise in patients with NF-1, and therefore these patients should be thoroughly investigated for any new symptoms or masses. MPNST of the brachial plexus should be treated with an adequate wide local excision, with adjuvant high-dose radiotherapy pre- or postoperatively. The role of chemotherapy in the treatment of MPNST is not clearly defined, but it may have some benefit in salvaging treatment failures.

Adult↗
PubMed2007

Hepatoblastoma in a child with neurofibromatosis type I.

A major hallmark of NF1 is the development of benign tumors, including peripheral neurofibromas, plexiform neurofibromas, gliomas of the optic tract, other low grade gliomas, and pheochromocytomas. Hepatoblastoma have not been previously reported in patients with neurofibromatosis type 1. We present a case of a 9-month-old boy diagnosed with both hepatoblastoma and neurofibromatosis type 1. Hepatoblastoma occurs in association with several well-described cancer predisposition syndromes, including familial adenomatous polyposis, Beckwith-Wiedemann syndrome, Li-Fraumeni syndrome, trisomy 18, and glycogen storage disease type I. This paper describes a case of hepatoblastoma diagnosed in association with neurofibromatosis type 1.

Biomarkers, Tumor↗
PubMed1994

Involvement of spinal nerves in neurofibromatosis.

Spinal tumors are a frequent form of manifestation of neurofibromatosis. Out of 171 patients, who have been operated on over a ten years period on spinal tumors, 7 patients had neurofibromatosis (4.1%). A total of 9 operations were performed, removing 20 spinal tumors. Three patients had multiple neurofibromas. Half of the neurofibromas had a dumbbell configuration with a larger extraspinal extension. In three patients a family history of neurofibromatosis and typical dermatological signs were evident. Two cases will be selected and the basic concept regarding treatment and the risks involved will be discussed.

Adolescent↗
PubMed1986

Cell culture studies on neurofibromatosis (von Recklinghausen's disease). IV. Collagen synthesis.

Comparative measurements of collagen synthesis as a portion of total protein synthesis were performed with fragments of peripheral neurofibromas, of skin adjacent to the tumors, and of unaffected skin from patients with neurofibromatosis (NF). No significant difference was found among these various samples. Collagen synthesis was also measured in cell cultures derived from peripheral neurofibromas of eight NF patients and from skin of ten healthy donors. No differences observed in the following respective parameters: dependence on the concentration of fetal calf serum; dependence on cell population density; portion of synthesized collagens in the culture medium and the cell layer. The ratios of synthesized collagen types III to type I, determined in five pairs of NF and control strains, vary within the same range.

Cell Count↗
PubMed1992

Trigeminal neuromas: assessment of MRI and CT.

We report four cases of trigeminal neuroma. One of the patients had von Recklinghausen's neurofibromatosis with plexiform neurofibromas of the branches of the trigeminal nerve. MRI provided more information than CT as regards the spread of tumour: extension to the mandibular and maxillary division of the trigeminal nerve was well demonstrated on sagittal and coronal sections. This examination yielded an accurate census of the intraocular plexiform neurofibromas and allowed a correct preoperative diagnosis to be obtained. With Gd-DOTA, better definition of the outline of the tumours and of cystic components was obtained. However, CT was better for demonstration of bone erosions.

Adult↗
PubMed1995

Epidural analgesia for labour in a parturient with neurofibromatosis.

The first report of epidural analgesia for labour in a 26-yr-old woman with von Recklinghausen's neurofibromatosis is described. Epidural anaesthesia is often considered as contraindicated because neurofibromas may involve spinal cord and nerve roots. However, general anaesthesia was considered at high risk for this parturient on the basis of her previous medical and surgical history and of physical findings. The present observation suggests that epidural analgesia may be used in such circumstances provided that spinal cord neurofibromas have been ruled out by clinical and CT scan (or magnetic resonance imaging) examination.

Adult↗
PubMed2003

Malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1.

We report 4 cases of malignant peripheral nerve sheath tumors (MPNST) with neurofibromatosis type 1 (NF1). Mean age was 29.5. Two of them had a family history. Three of them were male. All of them had enlarging mass and pain in the background of neurofibromas. Locations were popliteal, thigh and forearm. The masses were greater than 5 cm in diameter in each case. In two cases the mass was showing continuity with a nerve. One patient had a nonossifying fibroma as well as a MPNST. Wide excision and radiotherapy were applied to three of the patients. One of them did not take any therapy after surgical resection. Two of the patients died of lung metastases after a mean period of 12.5 months. In a majority of NF1 patients MPNST emerges from a preexisting neurofibroma. The patients with NF1 are at greatest risk for developing sarcomas, so they should be followed closely.

Adult↗
PubMed1998

[Intrathoracic vagal nerve schwannoma preoperative diagnosis is correct because of clinical and characteristic CT findings--a case report and review of the literature].

A 60-year-old man was operated with the clinical diagnosis of intrathoracic vagal nerve schwannoma because of characteristic CT findings and no symptom of neurofibromatosis. Thoracoscopic surgery was performed and it was confirmed pathologically. Intrathoracic vagal nerve tumor is rare, so preoperative diagnosis seems to be difficult. We review the intrathoracic vagal nerve tumors reported in Japan (52 cases of schwannoma and 9 cases of neurofibroma), and analyzed the tumor location, furthermore, the relationship of neurofibromatosis and schwannoma and neurofibroma on vagal nerve tumor.

Humans↗
PubMed2000

[Bilateral segmental neurofibromatosis simulating epidermal nevus].

Neurofibromatosis is a neuroectodermal systemic disease. A rare variant of this condition is bilateral segmental neurofibromatosis. A 29-year-old man presented with bilateral papillomatous plaques in the lumbar dermatomes. Clinically, the lesions were very similar to an epidermal nevus but histologic examination revealed superficial neurofibromas. Family history, ophthalmologic and neurologic investigations were unremarkable. The unusual morphologic presentation of bilateral segmental neurofibromas in this case points to the wide clinical spectrum of the disease and the significance of histologic examination in systematic nevoid lesions.

Adult↗
PubMed2004

MR imaging of abdominopelvic involvement in neurofibromatosis type 1: a review of 43 patients.

BACKGROUND: Plexiform neurofibromas are a frequent complication of neurofibromatosis type 1. This article discusses MR imaging findings and distribution of plexiform neurofibromas in the abdomen and pelvis. OBJECTIVE: To define the most prevalent patterns of involvement and MR imaging findings in abdominopelvic neurofibromatosis type 1. MATERIALS AND METHODS: We reviewed the MR appearance of abdominopelvic lesions in 23 male and 20 female patients (median age: 16 years) with type 1 neurofibromatosis. The patients were part of a multi-institutional study of 300 patients. Imaging included coronal or sagittal, and axial short tau inversion recovery images. RESULTS: The most common abdominopelvic involvement was in the abdominopelvic wall (n=28, 65%) and lumbosacral plexus (n=27, 63%). Retroperitoneal involvement was frequent (n=15, 35%). Lesions were less often intraperitoneal (21%) (P=0.001). Pelvic disease (n=27, 63%), neural canal involvement (n=18, 42%), and hydronephrosis (n=4, 9%) were also noted. Target-like appearance of plexiform lesions was noted in more than half the patients. CONCLUSION: Abdominopelvic involvement in neurofibromatosis type 1 is primarily extraperitoneal. Although lesions are most prevalent in the abdominopelvic wall and lumbosacral plexus, retroperitoneal and pelvic involvement is common and usually affects important organs. MR imaging added information in the initial and follow-up clinical evaluation of these patients.

Abdomen↗
PubMed2000

Deep-seated segmental neurofibromatosis without café au lait spots.

Segmental neurofibromatosis is a rare disease characterized by neurofibromas with or without café au lait spots localized to one segment of the body. The majority of reported cases have had cutaneous neurofibromas, and patients with deep involvement have rarely been described. We report on two patients with deep-seated segmental plexiform neurofibromatosis and review the literature. All reviewed cases including the present two had no café au lait spots, axillary freckling, Lisch nodules, family history or malignant progression of disease. Differential diagnoses from neuro-fibromatosis 1 (von Recklinghausen disease) and malignant peripheral nerve sheath tumor are important for genetic counseling and avoiding overtreatment.

Adult↗
PubMedDate not supplied

Mesenteric involvement in neurofibromatosis type 1: CT and MRI findings in two cases.

We report computerized tomographic and magnetic resonance imaging findings of neurofibromatosis type 1 with mesenteric involvement in two patients. The first patient was a 13-year-old female with a panmesenteric plexiform neurofibroma with segmental involvement of the bowel wall; she had a 3-year history of abdominal pain. The second patient was a 60-year-old female who presented with malignant transformation of multiple mesenteric neurofibromas 4 months after primary operation.

Adolescent↗
PubMed2004

Pediatric brain MRI in neurofibromatosis type I.

Neurofibromatosis (NF) is the most common of the phakomatoses, with a prevalence of 1 in 3-4,000. Many organ systems can be affected. In addition to multiple peripheral neurofibromas, NF I predisposed to CNS tumors including optic glioma, astrocytoma and plexiform neurofibroma. The purpose of this pictorial review is to illustrate characteristic brain MR imaging lesions in children with NF I and to give some recommendations about diagnostic imaging procedures in children suffering from NF I. Typical findings in brain MRI are hyperintense lesion on T2-weighted images, so-called unknown bright objects, which may be useful as an additional imaging criterion for NF I. Contrast administration is necessary in MR studies to maximize tumor detection and characterization, to add confidence to the diagnosis of benign probable myelin vacuolization, and to document stability of neoplasm on follow-up examinations. We recommend to perform serial MR imaging in children every 12 months. The frequency of follow-up in children with known brain tumors will vary with the tumor grade, biological activity and treatment.

Adolescent↗
PubMed2002

Expression of survivin, an inhibitor of apoptosis protein, in tumors of the nervous system.

Survivin is an inhibitor of apoptosis protein that blocks apoptosis by binding to caspases-3 and -7. It is highly expressed in less-differentiated embryonic cells and rapidly dividing tumors, but not in terminally differentiated adult tissues. Elevated survivin levels are found in malignant systemic tumors, and are associated with chemo-resistance, radiation resistance, and poor prognosis. However, expression of survivin in primary nervous system tumors has not been previously characterized. Immunohistochemistry using anti-human survivin antibody (SURV11-A) was performed on formalin-fixed, paraffin-embedded archival tissue from 112 primary central nervous system tumors. Survivin immunoreactivity was seen in most diffuse astrocytomas [WHO II (2/4), III (3/3), IV (9/10), giant-cell glioblastoma (1), and gliosarcoma (1)]. The intensity and degree of survivin expression showed trends with tumor grade, with glioblastomas having the highest positivity. Pilocytic astrocytomas (5) and pleomorphic xanthoastrocytoma (1) were positive to a lesser degree. In oligodendrogliomas (6) and mixed oligo-astrocytomas [grade II (5), II-III (3), and III (7)], oligodendroglial elements appear to be negative compared to positive mini-gemistocytic oligodendrocytes. Ependymomas [grade II (6) and grade III (1)] were positive. Medulloblastomas (5) and retinoblastoma (1/4) showed focal positivity. All meningiomas [grade I (12), II (9), III (4), and grade I (3) and II (5) with frank brain invasion] were intensely positive. All schwannomas (11) and neurofibromas (6) were intensely positive. Thus, survivin is expressed in the majority of the primary nervous system tumors, particularly in glioblastomas, meningiomas, schwannomas and neurofibromas. Overexpression of survivin in meningiomas and benign peripheral nerve sheath tumors contrasts with previous reports relating it to rapid division and poor prognosis.

Astrocytoma↗
PubMed2002

Patterns of associations of clinical features in neurofibromatosis 1 (NF1).

Neurofibromatosis 1 (NF1) is a common, fully penetrant autosomal dominant disease. The clinical course is generally progressive but highly variable, and the pathogenesis is poorly understood. We studied statistical associations among 13 of the most common or important clinical features in data from four separate sets of NF1 patients: a "developmental sample" of 1,413 probands from the NNFF International Database, an independent "validation sample" of 1,384 probands from the same database, 511 affected relatives of these probands, and 441 patients from a population-based registry in northwest England. We developed logistic regressive models for each of the 13 features using the developmental sample and attempted to validate these models in the other three samples. Age and gender were included as covariates in all models. Models were successfully developed and validated for ten of the 13 features analysed. The results are consistent with grouping nine of the clinical features into three sets: (1) café-au-lait spots, intertriginous freckling and Lisch nodules; (2) cutaneous, subcutaneous and plexiform neurofibromas; (3) macrocephaly, optic glioma and other neoplasms. In addition, three-way interactions among café-au-lait spots, intertriginous freckling and subcutaneous neurofibromas indicate that the first two groups are not independent. Our studies show that some individuals with NF1 are more likely than others to develop certain clinical features of the disease. Some NF1 features appear to share pathogenic mechanisms that are not common to all features.

Humans↗
PubMed2005

Extensively high load of internal tumors determined by whole body MRI scanning in a patient with neurofibromatosis type 1 and a non-LCR-mediated 2-Mb deletion in 17q11.2.

Deletions in 17q11.2 affecting the NF1 gene and surrounding regions occur in 5% of patients with NF1. The two major types of NF1 deletions encompass 1.4-Mb and 1.2-Mb, respectively, and have breakpoints in the NF1 low-copy repeats or in the JJAZ gene and its pseudogene. Deletions larger than 1.4-Mb are rare, and only seven cases have been reported so far. Here, we describe a 26-year-old NF1 patient with an "atypical" NF1 deletion of 2-Mb. In contrast to the 1.4-Mb deletions, which preferentially occur by interchromosomal recombination during maternal meiosis, the deletion described here occurred intrachromosomally on the paternal chromosome. The centromeric deletion breakpoint lies in an L1-element located 1.3-Mb proximal to the NF1 gene. The telomeric deletion boundary is located in a single copy segment between an AT-rich segment and an AluSx-element in intron 15 of the JJAZ1 gene. Structural analysis implies that non-B DNA conformations at the breakpoints destabilized the duplex DNA and caused double-strand breaks. Although the breakpoints of this 2-Mb deletion are not recurrent, it is conspicuous that one breakpoint is located in the JJAZ1 gene. Paralogous recombination between the JJAZ1 gene and its pseudogene causes the recurrent 1.2 Mb deletions. The genomic architecture of the NF1 gene region, influenced by paralogous sequences such as the JJAZ1 gene and its pseudogene, seems also to stimulate the occurrence of non-recurrent deletions mediated by non-homologous end joining. Patient 442 described here suffers from a very high burden of subdermal neurofibromas. Magnetic resonance imaging of the whole body revealed numerous internal tumors, mainly plexiform neurofibromas and spinal tumors. This demonstrates the value of whole-body MRI scanning in determining the total tumor load, which is an important aspect in genotype/phenotype correlations with regard to large NF1 deletions.

Adult↗