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PubMedDate not supplied

[Unilateral facial and cerebral hyperplasia associated with neurofibromatosis type 1. Report of four patients].

INTRODUCTION: Plexiform neurofibroma in any location is one of the commonest complications associated with neurofibromatosis type 1 (NF1). Plexiform neurofibroma of the upper eyelid and orbit is usually associated with ipsilateral hemifacial hyperplasia. We present four patients with NF1 and plexiform neurofibroma of the eyelid and orbit associated with hemifacial hyperplasia, who also showed hyperplasia of the unilateral cerebral hemisphere. CASE REPORTS: There are four patients, three females and one male, who consulted because of NF1 with plexiform neurofibroma of upper eyelid and hemifacial hyperplasia. Upper eyelid involvement was observed since birth and progressed during the first years of life. The patients showed normal neurological and mental development without motor or cerebellar disorders. Magnetic resonance studies demonstrated the asymmetric hyperplasia of the ipsilateral hemisphere in all four cases and of the cerebellar hemisphere in one case. The degree of hemispheric hyperplasia was related to the size and extension of the plexiform neurofibroma, as well as to the severity of the hemifacial hyperplasia. In our case which had the plexiform neurofibroma extended to the neck and the upper thorax, the hyperplasia not only affected the cerebral hemisphere but also the ipsilateral cerebellar hemisphere. All parts of the hemisphere showed increased size. The cortex of the entire hemisphere showed normal differentiation of the subcortical white matter. CONCLUSION: NF1 appears to be related with facial and cerebral ipsilateral hemihyperplasia. The relation between the size and extension of the orbital, eyelid and facial plexiform neurofibroma and the degree of asymmetry of the hemispheric hyperplasia suggest that different influences of a still unknown agent, possibly a gene, obviously related to NF1, causes both the intracranial and extracranial abnormalities.

Adolescent↗
PubMedDate not supplied

Peripheral nerve sheath tumors from patients with neurofibromatosis type 1 do not have the chromosomal translocation t(X;18).

Neurofibromatosis type 1 (NF1) is a common autosomal dominant genetic disorder that is caused by a mutation in the NF1 gene. Hallmark characteristics include dermal neurofibromas, café-au-lait spots, and learning disabilities. In approximately 25% of NF1 cases, plexiform neurofibromas, or peripheral nerve sheath tumors (PNSTs) that involve large segments of nerve sheath and nerve root, can form, of which a small percentage become malignant (MPNST). Most MPNSTs are composed of spindled neoplastic cells, and they can resemble other spindle-cell sarcomas, including leiomyosarcoma and monophasic synovial sarcoma. Histological diagnosis of MPNST is not always straightforward, and various immunohistochemical and molecular adjuncts can be critical in establishing a correct diagnosis. One example of genetic testing is the assay for the t(X;18) chromosomal translocation, which has been found to be common in synovial sarcomas. The aim of this study was to determine whether MPNSTs contain the t(X;18) chromosomal translocation. To detect the t(X;18) translocation product, SYT-SSX, total RNA was extracted from frozen archival tumors (15 dermal neurofibromas, 4 plexiform neurofibromas, and 7 MPNSTs) using Trizol. The RNA was then subjected to reverse-transcriptase polymerase chain reaction (RT-PCR) to specifically amplify SYT-SSX. None of the dermal neurofibromas, plexiform neurofibromas, or MPNSTs analyzed were positive for SYT-SSX mRNA. The results indicate that the t(X;18) translocation is absent in neurofibromas and is not a marker for MPNST in patients with NF1.

Biomarkers, Tumor↗
PubMed1998

[Extracerebral neoplastic manifestations in neurofibromatosis 1: integrated diagnostic imaging].

PURPOSE: To analyze the extracerebral manifestations of type 1 neurofibromatosis (NF-1), with special reference to peripheral nerve tumors. MATERIAL AND METHODS: The findings of 376 NF-1 patients (194 men and 182 women; age range: 0.1-48 years, mean: 8.1) were retrospectively reviewed. The patients had been submitted to abdominopelvic and superficial US and, in case of abnormal US findings or in the presence of symptoms, to CT and/or MRI. In addition, we considered 5 more patients (2 men and 3 women; age range: 50-72 years, mean: 64.4) with incomplete forms of NF-1 diagnosed after the finding of nerve sheath tumors. Biopsy (12 cases), surgery (10 cases), or clinical-instrumental follow-up were the study criteria. RESULTS: In the first group of patients we identified 91 cutaneous, 222 subcutaneous, 11 pendulous and 25 internal neurofibromas. Plexiform neurofibromas were found in the neck (1 case), chest (6 cases), abdomen (16), pelvis (8). We also found 1 benign and 1 malignant Schwannomas, 2 nerve sheath fibrosarcomas, 1 dopamine-producing sympatoma and 1 spermacytoma. As for the second group of patients, we had 2 Schwannomas, 1 pulmonary neurofibroma, and 2 multiple plexiform neurofibromas. The neurofibromas exhibited homogeneous US hypoechogenicity or slight echogenicity, with little contrast enhancement at CT. MR showed peripheral hyperintensity and central hypointensity on T2-weighted sequences and marked contrast enhancement after gadolinium, sometimes with mostly central uptake. The plexiform neurofibromas, which are typical of NF-1, had poorly-defined or infiltrating margins, with similar findings to the previous ones but sometimes with less homogeneous patterns at both US and CT. The Schwannomas, which are a less common finding in NF-1, exhibited different features at MRI and CT, namely pseudo-liquid or solid-inhomogeneous patterns with irregular and inhomogeneous contrast enhancement relative to the Antoni A/B tumor component. In the malignant lesions we observed infiltrating patterns, with irregular and inhomogeneous contrast enhancement, arranged asymmetrically relative to the contralateral lesion. CONCLUSIONS: Extra-axial neoplasms are a frequent finding in NF-1. Despite the extremely variable appearances of some lesions (particularly Schwannomas), the typical plexiform neurofibroma exhibits characteristic patterns. The diagnosis of malignancy often requires bioptic confirmation.

Adolescent↗
PubMed1997

Benign neural sheath tumours of major nerves: characteristics in 119 surgical cases.

Peripheral benign nerve sheath tumours are infrequent tumours and affect major nerve trunks. Some authors have indicated a high and prohibitive incidence of neurological injury in resection of these lesions. The authors describe their findings in a retrospective study comprising 119 patients with spontaneous benign nerve sheath tumours of the peripheral nervous system. Seventy-three patients had a schwannoma, 41 had neurofibroma and 5 had plexiform neurofibroma; 25 of the 119 patients suffered from neurofibromatosis. All schwannomas were excised completely and the outcome of patients was 41.0% improved, 6.8% worsened, 52.0% unchanged. Twenty-eight neurofibromas were excised completely and 13 subtotally; the outcome for patients was 19.5% improved, 19.5% worsened and 61% unchanged. All plexiform neurofibromas were removed subtotally and the outcome for patients was 20% improved and 80% unchanged. The best surgical results at average follow-up of 6 years were observed in the patients with schwannoma, the worst in those with plexiform neurofibroma. Our results demonstrated that it is often possible to remove schwannomas as well as neurofibromas with an acceptable risk of injury to the nerve.

Adult↗
PubMed2004

Molecular profiling of malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1, based on large-scale real-time RT-PCR.

BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex range of clinical symptoms. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors (MPNSTs), and the underlying molecular mechanisms are largely unknown. RESULTS: To obtain further insight into the molecular pathogenesis of MPNSTs, we used real-time quantitative RT-PCR to quantify the mRNA expression of 489 selected genes in MPNSTs, in comparison with plexiform neurofibromas. The expression of 28 (5.7%) of the 489 genes was significantly different between MPNSTs and plexiform neurofibromas; 16 genes were upregulated and 12 were downregulated in MPNSTs. The altered genes were mainly involved in cell proliferation (MKI67, TOP2A, CCNE2), senescence (TERT, TERC), apoptosis (BIRC5/Survivin, TP73) and extracellular matrix remodeling (MMP13, MMP9, TIMP4, ITGB4). More interestingly, other genes were involved in the Ras signaling pathway (RASSF2, HMMR/RHAMM) and the Hedgehog-Gli signaling pathway (DHH, PTCH2). Several of the down-regulated genes were Schwann cell-specific (L1CAM, MPZ, S100B, SOX10, ERBB3) or mast cell-specific (CMA1, TPSB), pointing to a depletion and/or dedifferentiation of Schwann cells and mast cells during malignant transformation of plexiform neurofibromas. CONCLUSION: These data suggest that a limited number of signaling pathways, and particularly the Hedgehog-Gli signaling pathway, may be involved in malignant transformation of plexiform neurofibromas. Some of the relevant genes or their products warrant further investigation as potential therapeutic targets in NF1.

Adolescent↗
PubMedDate not supplied

Expression of emmprin and matrix metalloproteinases (MMPs) in peripheral nerve sheath tumors: emmprin and membrane-type (MT)1-MMP expressions are associated with malignant potential.

BACKGROUND: Matrix metalloproteinases (MMPs), including membrane-type (MT)-MMPs, correlate with biological aggressiveness in many carcinomas. However, their roles in peripheral nerve sheath tumors (PNSTs) have rarely been investigated. MATERIALS AND METHODS: In this study, the immunohistochemical expression of 6 MMPs, their 3 inhibitors and emmprin, an MMP inducer, was examined in 14 schwannomas, 14 neurofibromas and 12 malignant peripheral nerve sheath tumors (MPNSTs) in relation to malignant potentials. RESULTS: Higher expression levels (>3+) of emmprin and MT1-MMP were noted in 83.3% and 16.7% of MPNSTs, respectively, versus none in schwannomas and neurofibromas (p<0.0001). The overall expression rate (1-4+) of MT1-MMP was 58.3% in MPNSTs versus 7.1% in both schwannomas and neurofibromas (p=0.0093). Gelatinase A (MMP-2) showed higher expression levels (>3+) in all the tumors without significant differencies. Moreover, the expression patterns of MMP-1 and gelatinase B (MMP-9) could divide PNSTs into two groups: schwannoma versus neurofibroma/MPNST. Higher expression levels (>3+) of MMP-9 were observed in 50% of schwannomas versus none in neurofibromas and MPNSTs, while those of MMP-1 were found in 35.7% of neurofibromas and 66.7% of MPNSTs versus none in schwannomas. RECK was the main inhibitor expressed in these 3 tumors, with no significant differences. CONCLUSION: These results suggest that emmprin and MT1-MMP may be malignant potential-related proteins in PNSTs, and that MMP-1 and 9 may help differentiation between schwannoma and neurofibroma, especially in their plexiform types.

Adolescent↗
PubMed2005

[Imaging features of neurofibromatosis type 1].

Neurofibromatosis type 1 (NF1) is the most common of all the phakomatoses. It is an autosomal dominant disorder, with about 50% of patients being new mutations. NF1 is diagnosed based on the presence of well established diagnostic criteria. Prominent cutaneous manifestations include cafe-au-lait spots, freckling and cutaneous neurofibromas. CNS lesions are frequent and imaging is valuable for diagnosis, treatment and follow-up of patients. Tumors of the central nervous system are frequent. Optic nerve glioma usually affects younger patients with clinical symptoms in one third of cases. MRI shows fusiform enlargement with variable enhancement of the optic nerve. These tumors are usually non-aggressive with good prognosis. Other gliomas and astrocytomas can occur as well, usually midline in location, that also generally have good prognosis. Non-tumoral white matter lesions, referred as unidentified bright objects or UBO's, are frequently observed, typically in the basal ganglia and posterior fossa structures. These lesions are usually seen during childhood and they typically diminish with age. The distinction between UBO's and other tumors may be difficult to achieve at imaging, and a malignant evolution may very rarely be observed. Patients with NF1 may have hydrocephalus and dural sac anomalies leading to meningocele formation. Neurofibromas and plexiform neurofibromas involve peripheral nerves and nerve sheaths. Plexiform neurofibromas may cause radicular symptoms. They more frequently involve the lumbosacral plexus. Neurofibromas are homogeneous oval shaped tumors that may extend into the spinal canal. Neurofibrosarcoma is the main cause of death of NF1 patients less than 40 years of age. It may develop de novo or from sarcomatous degeneration of a pre-existing plexiform neurofibroma. It should be suspected in patients with new onset of symptoms or patients with changing symptoms. At imaging, it is characterized by a large heterogeneous tumor invading adjacent structures. Osseous lesions have been described including progressive thoracic scoliosis, vertebral anomalies (posterior scalloping is very suggestive), long bones anomalies with frequent bowing of the tibia, sometimes resulting in pseudarthrosis, and rib anomalies with ribbon ribs. Vascular lesions may occur resulting in arterial hypertension and aneurysm formation.

Bone Neoplasms↗
PubMed2004

Neurofibromatosis 1-associated neuropathies: a reappraisal.

Neurofibromatosis 1 (NF1) is a common disease which is a source of various multisystemic manifestations related either to the accumulation of neurofibromas or to specific developmental abnormalities. The neurofibroma is the hallmark lesion of NF1 and develops from peripheral nerves. However, to date, the description of peripheral neuropathies of NF1 has not been investigated. To examine this question, we have evaluated 688 NF1 patients for the presentation, prognosis and associated morbidity of peripheral neuropathies in two hospital-based series. We collected 18 patients (four women and 14 men) with diffuse peripheral neuropathy (2.3%). Eight patients had a paucisymptomatic or an asymptomatic neuropathy detected only on electrophysiological study, two had minor sensory manifestations, five had moderate motor and sensory manifestations and three had severe motor and sensory manifestations. Superimposed radicular changes were observed in seven cases. Two patients had a subacute and 16 a chronic polyneuropathy. Fourteen patients had a demyelinating neuropathy with either severe axonal changes (three), moderate or minor axonal changes (four) or no axonal changes (seven). Four patients had axonal neuropathies. There was a strong association between the presence of a peripheral neuropathy and large root diffuse neurofibromas (P < 0.03) and subcutaneous neurofibromas (P < 0.0001). Severe morbidity and mortality of patients with NF1 and peripheral neuropathies was 50%, much higher than what is observed in the general population of patients with NF1, and 100% in patients with the most severe symptoms and electrophysiological changes (demyelination with severe axonal features). Four patients out of 18 (22%) developed a malignant peripheral nerve sheath tumour (MPNST), a much higher proportion than in the whole population of NF1. Two patients died. Peripheral neuropathy constitutes a potentially severe complication in patients with NF1 associated with a frequent morbidity related to spinal complications and MPNSTs. Association of proximal large neurofibromas, peripheral neuropathies and subcutaneous neurofibromas may constitute a phenotype of NF1 with a severe prognosis.

Adolescent↗
PubMed2004

Tumor suppressor mutations and growth factor signaling in the pathogenesis of NF1-associated peripheral nerve sheath tumors. I. The role of tumor suppressor mutations.

Patients with neurofibromatosis type 1 (NF1), a common autosomal dominant tumor predisposition syndrome, develop benign cutaneous, intraneural, and plexiform neurofibromas and malignant peripheral nerve sheath tumors (MPNSTs), an aggressive form of Schwann cell neoplasm that frequently arises from plexiform neurofibromas. Impressive advances have been made in defining the molecular mechanisms responsible for neurofibroma and MPNST tumorigenesis, including the identification of key tumor suppressor gene mutations, an improved understanding of the functions of these tumor suppressors, and the production of transgenic mouse models in which tumor suppressor gene mutations predispose animals to the development of neurofibromas and MPNSTs. It has also become apparent that dysregulated growth factor signaling cooperates with tumor suppressor mutations to promote neurofibroma and MPNST tumorigenesis. In Part I of this two-part review, we consider findings demonstrating that Schwann cells are the primary neoplastic cell type in neurofibromas and MPNSTs and that specific tumor suppressor gene mutations promote the development of these tumors. In Part II, which will be published in a later issue, we will review evidence indicating that inappropriate growth factor signaling contributes to this process by stimulating the proliferation, survival, and migration of Schwann cells whose regulatory mechanisms have been crippled by a loss of tumor suppressor function.

Animals↗
PubMed2005

Tumor suppressor mutations and growth factor signaling in the pathogenesis of NF1-associated peripheral nerve sheath tumors: II. The role of dysregulated growth factor signaling.

Patients with neurofibromatosis type 1 (NF1), one of the most common genetic disease affecting the nervous system, develop multiple neurofibromas that can transform into aggressive sarcomas known as malignant peripheral nerve sheath tumors (MPNSTs). Studies of human tumors and newly developed transgenic mouse models indicate that Schwann cells are the primary neoplastic cell type in neurofibromas and MPNSTs and that development of these peripheral nerve sheath tumors involves mutations of multiple tumor suppressor genes. However, it is widely held that tumor suppressor mutations alone are not sufficient to induce peripheral nerve sheath tumor formation and that dysregulated growth factor signaling cooperates with these mutations to promote neurofibroma and MPNST tumorigenesis. In Part I of this review, we discussed findings demonstrating that a loss of NF1 tumor suppressor gene function in neoplastic Schwann cells is a key early step in neurofibroma formation and that progression from neurofibroma to MPNST is associated with abnormalities of additional tumor suppressor genes, including p53, INK4A, andp27(kip1). In Part II of this review, we consider evidence that dysregulated signaling by specific growth factors and growth factor receptors promotes the proliferation, migration, and survival of neoplastic Schwann cells in neurofibromas and MPNSTs.

Animals↗
PubMed1995

Differences in proliferation and invasion by normal, transformed and NF1 Schwann cell cultures are influenced by matrix metalloproteinase expression.

Loss of negative growth regulation and high invasive potential are neoplastic traits often associated with abnormal expression of matrix metalloproteinases (MMPs). We previously found MMP-3 (stromelysin/transin) was secreted by quiescent rat Schwann cell cultures and expressed potent antiproliferative activity. In the present study we observed that human Schwann cells and cutaneous neurofibroma Schwann cell cultures secreted abundant MMP-3 and their proliferation was inhibited by autologous and rat Schwann cell conditioned media. Antiproliferative activities were depleted by immunoadsorption with anti-stromelysin antibodies. In contrast, plexiform neurofibroma cultures did not secrete MMP-3 and failed to respond to Schwann cell antiproliferative activities associated with MMP-3. Quiescent Schwann cells constitutively secreted low levels of MMP-2 (gelatinase A) and showed a low invasion potential in filter-based assays of basement membrane invasion. Cyclic AMP elevation, which profoundly influences cell differentiation, increased the invasion potential of rat Schwann cells and caused a corresponding increase in secretion of MMP-2. Schwann cells immortalized by protracted elevation of cAMP, as well as a schwannoma cell line (D6P2T), also rapidly invaded a reconstituted basement membrane and over-expressed MMP-2. Similarly, neurofibroma Schwann cells were highly invasive and secreted up to 10-fold more MMP-2 than normal human Schwann cells. Additionally, only cutaneous neurofibroma Schwann cell cultures secreted MMP-9 (gelatinase B) and MMP-1 (interstitial collagenase) and also invaded native type I collagen barriers. Cultures of normal Schwann cells and plexiform neurofibroma tumor expressed little or no MMP-1 and did not invade type I collagen barriers. These results suggest a role for MMPs in the control of proliferation and invasion by Schwann cells and in the formation of peripheral nerve sheath tumors.

Amino Acid Sequence↗
PubMed1988

Extracranial and extraspinal nerve sheath tumors: computed tomographic evaluation.

Thirty-five patients with 37 peripheral nerve sheath tumors (NST) (16 schwannomas, 11 neurofibromas, 5 plexiform and 1 diffuse neurofibroma, and 4 malignant NST) were studied respectively. The benign NST usually appeared on CT as well-defined oval, spherical or fusiform masses, centered at the expected anatomic location of a cranial, spinal, autonomic or peripheral nerve with characteristic displacement of adjacent muscles and blood vessels. None of the schwannomas appeared homogeneously hypodense on IV enhanced CT, whereas close to half of neurofibromas and plexiform neurofibromas were so. This fact, which had not been reported in the past, may be related to differences in inherent vascularity and blood-nerve barrier (fenestrated blood vessels) between schwannomas and neurofibromas and may be a useful distinguishing CT feature. The most reliable, though not infallible criterion of malignant NST was poor definition of their margins. Ninety-two per cent of NST (34 out of 37) were diagnosed or included in a limited differential pre-operatively.

Female↗
PubMed2003

Aberrant axon neurofilaments in schwannomas associated with phacomatoses.

Neurofibromas and schwannomas express S100 protein, while axon filaments are not commonly found in schwannomas. Histopathological distinction between neurofibromas and schwannomas is usually easy, except for some variants. To assess the reliability of immunohistochemistry results for the differential diagnosis of the latter, 46 neural tumors of the skin were studied: 31 schwannomas [12 schwannomatosis, 7 neurofibromatosis type 2 (NF2)-associated, 12 solitary] and 15 plexiform neurofibromas associated with neurofibromatosis type 1. All tumors were subjected to immunohistochemical-labeling studies with antibodies to S100 protein and axon-specific neurofilament proteins. All tumors were positive with anti-S100 protein antibody. Schwannomas were strongly and diffusely positive while neurofibromas displayed more varied and limited S100 protein reactivity. Axon filaments were detected in 15 of 15 plexiform neurofibromas and 7 of 19 schwannomas associated with NF2/schwannomatosis. None of the 12 solitary schwannomas reacted with anti-axon neurofilament antibodies. Aberrant axons were observed in the schwannomas associated with NF2/schwannomatosis but not in the solitary schwannomas. Therefore, when there are multiple neural tumors, immunohistochemical visualization of axons may be misleading if it is not related to the clinical context and the standard histological features.

Adolescent↗
PubMed2002

[Abnormalities of the maxillary sinus in type 1 neurofibromatosis].

AIM: The aim of this study was to determine the malformations of the maxillary sinus in neurofibromatosis type 1 patients (NF1). MATERIAL AND METHODS: Twenty-two patients with NF1 were investigated clinically and radiologically: 11 had an unilateral trigeminal plexiform neurofibroma and 11 had multiple cutaneous neurofibromas. The histological type of NF was ascertained in all cases following tumor resections. The malformation of the maxillary sinus was assessed on plain radiographs and computed or magnetic resonance tomograms. Intraindividual side comparison was used to judge the size of the sinus and its position in the midface. RESULTS: In patients with cutaneous neurofibromas the maxillary sinus appeared symmetrical in size and position. The pneumatization of the sinus had no abnormalities on the radiographs. Malformations of the maxillary sinus were restricted to plexiform neurofibromas. On the side affected by a plexiform NF, the sinus appeared hypoplastic and caudally displaced due to an enlarged ipsilateral orbit. The expansion of the sinus to the lateral side was impaired, obviously due to tumor masses. Consecutively, the alveolar process of the affected side was also displaced leading to a complex malocclusion. DISCUSSION: Malformations of the face are frequently presented as case reports in the literature. Emphasis is given to the elephantiasis-like tumor growth of the face in certain patients with NF1. The underlying pathology has not yet been fully understood. This report provides evidence that in the midfacial region the overgrowth is predominantly caused by the plexiform neurofibroma itself and that the bones can even be hypoplastic and show scoliosis-like malformation compared to the nonaffected side. These findings are relevant when debulking procedures of the face are planned for NF1 patients.

Adolescent↗
PubMed1997

Comparative immunoreactivity of CD-68 and HMB-45 in malignant melanoma, neural tumors and nevi.

The monoclonal antibody CD 68 (KP 1) reacts with fibrohistiocytic and some epithelial neoplasms; its reactivity compared with that of HMB 45 in malignant melanoma (MM) and neural tumors needs further elucidation. Using a streptavidin-biotin-immunoperoxidase procedure, we examined the reactivity of 65 MM (46 conventional, 1 polypoid, 6 desmoplastic [DMM], and 12 metastatic), 21 neurofibromas, 1 neurofibrosarcoma, 10 schwannomas, 1 perineurioma, 2 neurothekeomas, and 14 blue and 26 other nevi for CD-68, HMB-45-defined antigen, S 100 and neurofilament protein. A positive staining for CD 68 was observed in 38 of 42 primary, 5 of 6 DMM, and 11 of 12 metastatic melanomas; 6 of 10 schwannomas; 5 of 10 nevi with junctional component and all 14 blue nevi. All 21 neurofibromas, 1 each neurofibrosarcoma and perineurioma, both neurothekeomas, and all 12 nevi with dermal component were CD 68-negative. HBM 45 was expressed by all 44 primary, none of 6 DMM, and 7 of 12 metastatic melanomas; by none of 10 schwannomas, 6 neurofibromas, 1 neurofibrosarcoma, 1 perineurioma and 2 neurothekeomas. Both junctional nevi, 8 of 10 nevi with junctional components, 1 of 10 dermal components of junctional nevi, and 11 of 13 blue nevi were also HMB 45 positive. Except for 1 perineurioma, S 100 decorated all tumors examined. NF was immunoreactive in 1 of 45 conventional melanomas, 2 of 21 neurofibromas, 2 of 10 schwannomas, and 3 of 10 blue nevi; it was non-reactive in all polypoid, desmoplastic and metastatic melanomas; neurofibrosarcoma, perineurioma, neurothekeoma and other nevi. We conclude that the CD-68-reactivity in primary melanomas, neurofibromas, neurofibrosarcomas, perineuriomas, and nevi was similar to that of HMB 45. The significantly higher CD 68-positivity than of HMB 45 in metastatic and desmoplastic melanomas and schwannomas may be of diagnostic value.

Antigens, CD↗
PubMed2003

Jaw malformations plus displacement and numerical aberrations of teeth in neurofibromatosis type 1: a descriptive analysis of 48 patients based on panoramic radiographs and oral findings.

AIM: The aim of this study was to analyse jaw malformations and tooth displacement in patients with neurofibromatosis type 1 (NF1). MATERIAL AND METHODS: Forty-eight patients were included in the study (male or female 24 each). All fulfilled the current NIH diagnostic criteria for NF1. The age range was 2.5-66 years. The type of neurofibroma was histologically proven in surgically treated patients. Patients with disseminated cutaneous neurofibromata and those with the plexiform type were distinguished. The analysis was based on physical investigation, photographs, panoramic radiographs and dental casts. RESULTS: With the emphasis on alterations of tooth position, deformities of the adjacent bones and malocclusion, the majority of these patients (26) were affected by plexiform neurofibromata. In the other 22 patients with disseminated neurofibromata, malformations of the alveolar ridge were absent and individual oral symptoms were rarely found and were mild, and in all cases were unimpaired. Numerical aberrations and retention of molars was exclusively associated with a trigeminal nerve affected by plexiform neurofibroma. Aplasia of a second lower molar was recognized in four of these plexiform-neurofibroma patients. CONCLUSION: It is widely accepted that malformations of the facial skeleton are often of genetic origin. However, in this study these malformations were strongly associated with plexiform neurofibromata originating from the trigeminal nerve. Thus, in addition to presently unknown genetic factors, the pattern of skeletal malformation can be caused by tumour invasion and local destruction, e.g. the neuromuscular unit or prenatal development of the plexiform neurofibroma in the inferior alveolar nerve. It is further concluded that epidemiologic studies on the incidence and severity of NF1 in the oral and maxillofacial region have to distinguish between patients with or without plexiform neurofibroma, especially when analysing alterations and deformities of the jaws, teeth and malocclusion. Aplasia of second inferior molars is an additional (dental) finding associated with plexiform neurofibromata in NF1.

Adolescent↗
PubMed2001

Microphthalmia transcription factor and melanoma cell adhesion molecule expression distinguish desmoplastic/spindle cell melanoma from morphologic mimics.

Desmoplastic/spindle cell melanoma is a rare variant of melanoma. A number of factors complicate the diagnosis of desmoplastic/spindle cell melanoma, including the variable absence of a lentiginous component, its spindle cell morphology, and its many morphologic mimics, including scars, malignant peripheral nerve sheath tumor, neurofibroma, atypical fibroxanthoma, and spindled carcinoma. The immunohistochemical confirmation of desmoplastic/spindle cell melanoma may also be difficult, because the majority of tumors are negative for specific melanocytic markers such as HMB-45 and Melan-A, despite their usual expression of S-100 protein. Two new and potentially promising melanocytic markers, microphthalmia transcription factor (MiTF) and melanoma cell adhesion molecule (Mel-CAM), have been shown to be sensitive markers of epithelioid melanoma, but have not been tested in desmoplastic/spindle cell melanoma or in other rare melanocytic neuroectodermal tumors such as clear cell sarcoma. We immunostained 79 tumors (20 desmoplastic/spindle cell melanomas, 10 scars, 10 neurofibromas, 12 malignant peripheral nerve sheath tumors, 10 atypical fibroxanthomas, 10 clear cell sarcomas, 3 melanotic schwannomas, and 4 cellular blue nevi) for MiTF and Mel-CAM. MiTF expression was seen in 11 of 20 desmoplastic/spindle cell melanomas, 0 of 10 scars, 2 of 10 neurofibromas, 0 of 12 malignant peripheral nerve sheath tumors, 1 of 10 atypical fibroxanthomas, 7 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 3 of 4 cellular blue nevi. Mel-CAM expression was present in 14 of 17 desmoplastic/spindle cell melanomas, 0 of 10 scars, 4 of 10 neurofibromas, 3 of 11 malignant peripheral nerve sheath tumors, 0 of 10 atypical fibroxanthomas, 9 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 0 of 4 cellular blue nevi. MiTF and Mel-CAM were coexpressed in 6 of 17 desmoplastic/spindle cell melanomas and in no other tumor. Regarding desmoplastic/spindle cell melanoma, scar, neurofibroma, malignant peripheral nerve sheath tumor, and atypical fibroxanthoma, the sensitivity and specificity of MiTF for desmoplastic/spindle cell melanoma were 55% and 91%, respectively. For this same group of tumors, Mel-CAM had a sensitivity of 82% and a specificity of 83%. We conclude that the sensitivity and specificity of MiTF for desmoplastic melanoma equals or exceeds that of such markers as HMB-45 or Melan-A, and that MiTF should be part of the initial immunohistochemical panel for the work-up of such cases. Mel-CAM, while very sensitive, is relatively nonspecific, because it is also expressed in a variety of mesenchymal tumors and carcinomas. Mel-CAM is best reserved for cases morphologically suspected to be desmoplastic/ spindle cell melanoma, in which S-100 is positive and MiTF and other melanocytic markers are negative. These markers may also be helpful in certain other differential diagnoses, such as distinguishing clear cell sarcomas from epithelioid malignant peripheral nerve sheath tumors.

Antigens, CD↗
PubMed1983

Computed tomography of extracranial nerve sheath tumors with pathological correlation.

Computed tomography was obtained in 15 patients with extracranial nerve sheath tumors, including eight with neurofibromatosis. The studies included two schwannomas, six neurofibromas, four plexiform neurofibromas, and three neurofibrosarcomas. Lesions with attenuation values exceeding 30 Hounsfield units had dense bands of collagen in resected specimens. Eleven of the lesions had attenuation values which were significantly lower than muscle. Histological examination of hypodense lesions revealed five factors contributing to reduced attenuation values: (a) a population of lipid-rich Schwann cells; (b) the presence of adipocytes (transformed fibroblasts) in neurofibromas; (c) entrapment of perineural adipose tissue by plexiform neurofibromas; (d) a coalescence of interstitial fluid to form cystic spaces in schwannoma with Antoni B tissue; and (e) cystic degeneration secondary to infarction or necrosis within neurofibromas and neurofibrosarcomas.

Adolescent↗