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PubMed1980

The pathophysiology of neurofibromatosis. I. Resistance in vitro to 3-nitrotyrosine as an expression of the mutation.

The in vitro expression of the autosomal dominant mutation responsible for neurofibromatosis was probed using the amino acid analogue 3-nitrotyrosine as a cell culture selective agent. The presence of 3-nitrotyrosine in culture medium led to inhibition of growth and cell death among normal skin fibroblasts in log phase growth, whereas cell strains derived from six different patients' neurofibromas or skin cells, or both, exhibited a consistently enhanced ability to survive under the same conditions. At 0.8 mM 3-nitrotyrosine, four patient-derived skin fibroblast strains could be differentiated from five strains of control skin fibroblasts with a high level of confidence (P < 0.0000). In the same way four neurofibroma-derived fibroblast strains were differentiated from control skin fibroblasts (P < 0.0022). Neurofibroma-derived cells were not different from control cells when treated with 5-fluorotryptophan or p-fluorophenylalanine.

Adolescent↗

PubMed2005

Endobronchial neurogenic tumors treated by transbronchial electrical snaring and Nd-YAG laser abrasion: report of three cases.

Neurogenic benign tumors arising from the trachea and bronchus are relatively rare. We experienced three cases of neurofibroma of the bronchus which were successfully treated by transbronchial electrical snaring and Nd-YAG laser abrasion. The first was a 67-year-old man with right lung cancer, who was pointed out to have a neurofibroma in the left main bronchus. The second was a 34-year-old man with an obstruction in the right main bronchus due to neurofibroma. The third was a 66-year-old woman with a complete obstruction in the left main bronchus due to schwannoma. All patients were successfully treated to remove the tumors and obtain a patency of the bronchus by transbronchial electrical snaring and Nd-YAG laser abrasion. We also review 23 reported cases of endobronchial neurogenic tumors and discuss the efficacy of endoscopic treatments for endobronchial neurogenic tumors.

Adult↗

PubMedDate not supplied

p53 and Ki-67 proliferating cell nuclear antigen in benign and malignant peripheral nerve sheath tumors in children.

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon soft tissue tumors. In children with neurofibromatosis 1 (NF1), a MPNST often arises in a pre-existing neurofibroma, or may represent an initial manifestation without other obvious stigmata of the disease. The development of MPNSTs may be associated with instability of the p53 tumor suppressor gene since it is the most frequent genetic abnormality in soft tissue sarcomas. To assess the presence of p53 accumulation in MPNSTs and its correlation with clinical and pathologic features, we studied 12 neurofibromas (NFs), including 4 tumors with cellular features (one congenital) and 10 MPNSTs. Six MPNSTs were associated with NF1, all of which developed within a plexiform neurofibroma. Cell proliferation evaluated with an antibody to Ki-67 and nuclear p53 staining were both detected by immunohistochemistry. We found p53 positivity in 60% of MPNSTs. All NFs except the congenital tumor were p53 immunonegative (P < 0.01). Rare p53-positive nuclei were detected in the transitional zone in two of six MPNSTs arising in plexiform NFs. Ki-67 distinguished the NFs from MPNSTs (P < 0.005). Half of the NF1 patients with p53-positive MPNSTs developed recurrence or metastases or developed a second malignancy within 2 years of diagnosis, whereas patients with p53-positive sporadic MPNSTs were free of disease 1 to 7 years later. We found p53 accumulation more frequently in NF1-associated MPNSTs. p53 mutations may be an additional biologic factor to account for the poor prognosis in these tumors.

Adolescent↗

PubMed2004

Pathologic classification of peripheral nerve tumors.

Peripheral nerve tumors show an interesting histologic variety despite being composed ofa limited array of cellular constituents. As we learn more about the interplay between the Schwann cells, perineurial cells, and ganglion cells that comprise these tumors, it is likely that we will better understand the biologic behavior of these important tumors. Key issues for the pathologist include distinguishing schwannomas from neurofibromas, ganglioneuromas from neurofibromas involving ganglia, and MPNSTs from cellular schwannomas or neurofibromas. The association of each of these tumors with genetic tumor disorders provides a unique window into discovering basic mechanisms of cell regulation and tumorigenesis that may ultimately shed light on the biology of a much wider array of human disease.

Ganglioneuroma↗

PubMed1999

Peripheral nerve tumors of the orbit.

Neurofibromas and schwannomas are orbital neoplasms with similar clinical and radiologic features. Solitary or circumscribed neurofibromas and schwannomas demonstrate slow progressive growth with ocular displacement and are amenable to surgical resection. Plexiform and diffuse neurofibromas are diffusely infiltrative in the orbit and periocular region, they are difficult to resect, and they have a high rate of recurrence. Malignant peripheral nerve tumors are rare, but they have a very high rate of recurrence and a low 5-year survival rate because of extension through the superior orbital fissure to the midbrain region. This article describes the clinical and radiologic features of peripheral nerve sheath tumors.

Disease Progression↗

PubMed1991

Isolated peripheral nerve sheath tumours of the orbit.

Fifty-four cases of peripheral nerve sheath tumours within the orbit are reviewed. Benign neurilemmomas or neurofibromas occurred in 93% of patients and had an equal incidence. There was a family history or other signs of systemic neurofibromatosis in one-quarter of those with solitary neurofibromas, but in none of the patients with neurilemmoma. Symptoms and signs were generally those of an orbital mass lesion and pain or sensory loss was unusual, occurring more frequently with malignancy. Within the orbit, most peripheral nerve sheath tumours affect the first division of the trigeminal nerve and extension of some tumours through the superior orbital fissure limits their surgical resection. Despite incomplete resection of some tumours, with up to 23 years follow-up there have been no recurrences requiring further surgery. A postoperative sensory deficit occurred in only 32% of patients with benign neurilemmomas and 72% with neurofibromas.

Adolescent↗

PubMed1994

Cell culture studies on human nerve sheath tumors.

The main controversy about nerve sheath tumors (NSTs) has been their histogenesis. A Schwann cell origin has been proposed by many investigators for both schwannomas and neurofibromas. However Erlandson and Woodruff observed that while schwannomas appeared to be composed predominantly of Schwann cells, neurofibromas consisted of mainly perineurial cells. In addition, variable numbers of fibroblast-like cells and intermediate cells also have been reported in the 2 lesions. Whether these represent distinct cell types or variants of Schwann cells is still debatable. In an attempt to solve this controversy, the present study was undertaken to observe the morphology and the behaviour of these tumors in culture. These studies showed that all nerve sheath tumors are basically of Schwann cell origin and that intermediate cells and fibroblasts are variants of Schwann cell. Tissue culture studies done chiefly on schwannomas showed that the morphological features of schwannomas are preserved in 'in vitro culture' condition and therefore the difference between neurofibroma and schwannoma appears to be due to inherent differentiating property of the Schwann cells along with some environmental stimulus.

Adolescent↗

PubMed2000

Genetic and cellular defects contributing to benign tumor formation in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a common inherited cancer predisposition syndrome. The NF1 gene product, neurofibromin, is hypothesized to function as a tumor suppressor and nearly all NF1 patients develop benign peripheral nerve tumors. These neurofibromas presumably arise from NF1 inactivation in S100(+)Schwann cells, but there is no formal proof for this mechanism. We demonstrate that fibro-blasts isolated from neurofibromas carried at least one normal NF1 allele and expressed both NF1 mRNA and protein, whereas the S100(+)cells typically lacked the NF1 transcript. Our findings further indicate that additional molecular events aside from NF1 inactivation in Schwann cells and/or other neural crest derivatives contribute to neurofibroma formation.

Adult↗

PubMed1985

Pigmented dermatofibrosarcoma protuberans (Bednar tumor). A pathologic, ultrastructural, and immunohistochemical study.

Described by Bednar as a "storiform neurofibroma," pigmented dermatofibrosarcoma protuberans is a rare neoplasm accounting for approximately 1-5% of all cases of dermatofibrosarcoma protuberans (DFSP). The lesion commonly presents as an exophytic, multinodular neoplasm of the dermis or subcutaneous tissue. It occurs predominantly in blacks. The majority are located on the trunk, and the remainder are more or less equally distributed in the upper and the lower extremities and the head and neck. Microscopically the lesion is characterized by spindled cells arranged in a tight storiform pattern and admixed with a small population of melanin-containing dendritic cells. The dendritic cells are the primary feature distinguishing this lesion from conventional DFSP. Three cell populations are identifiable by electron microscopy. The majority of cells resemble fibroblasts. A second population of cells exhibits long slender cell processes partially or completely invested by basal lamina. The third population of cells, also invested by basal lamina, contains both melanosomes and premelanosomes. The histogenesis of this neoplasm remains controversial. Although Bednar considered these lesions as variants of neurofibroma, S-100 protein could not be identified, and this finding contrasts significantly from the description of conventional neurofibroma, which almost always contains this antigen. Follow-up information available in nine cases indicates that this lesion may recur locally. Although distant metastases were not observed in our material, complete excision in conjunction with close follow-up care is indicated for this neoplasm of probable intermediate malignant potential.

Adolescent↗

PubMed1997

Immunophenotyping of dermal spindle cell tumors: diagnostic value of monocyte marker Ki-M1p and histogenetic considerations.

Various studies have reported the utility of anti-CD34 staining in the differential diagnosis of dermal spindle-cell tumors. To investigate whether monoclonal antibody Ki-M1p might add practical diagnostic information, we examined a total of 120 cutaneous spindle cell neoplasms using a panel of markers. Anti-CD34 antibody QBEnd/10 consistently stained dermatofibrosarcomas, Kaposi's sarcomas, neurofibromas, and, to a lesser extent, hemangiopericytomas. A positive reaction was also found in > 18% of the dermatofibromas. Ki-M1p staining showed an intense immunoreaction in all dermatofibromas, whereas no reactivity was observed in dermatofibrosarcomas. In addition, a subset of cells was labeled in atypical fibroxanthomas and Kaposi's sarcomas. Neurofibromas, spindle-cell hemangioendotheliomas, and hemangiopericytomas were negative. Dermatofibrosarcomas and atypical fibroxanthomas also moderately expressed smooth muscle-specific actin. Immunohistochemically, a discrimination between dermatofibrosarcomas and neurofibromas was possible only by means of an antibody against the nerve growth factor receptor. We conclude that the combination of several antibodies, in particular anti-CD34 and Ki-M1p, may improve the accuracy of diagnostic immunohistochemistry in the field of cutaneous spindle cell tumors. We speculate that dermatofibroma is primarily a macrophage-rich inflammatory lesion in which cytokine secretion induces a secondary proliferation of fibroblasts, whereas dermatofibrosarcoma is likely to issue from primitive dermal cells of uncertain origin.

Antibodies, Monoclonal↗

PubMedDate not supplied

MR of benign peripheral nerve sheath tumors.

Seventeen benign peripheral nerve sheath tumors were studied using MR. In all cases T2 relaxation time, signal intensity on T1-weighted images (lesion/muscle ratio), detectability of nerve of origin, nerve-lesion relationship, and presence of a capsule were assessed. Sixteen tumors showed marked hyperintensity on T2-weighted images with T2 relaxation times values greater than 95 ms. One schwannoma was almost isointense with fat (T2 60 ms). All lesions were isointense with muscle on T1-weighted images. In schwannomas the nerve was usually situated at the periphery of the lesion and only in one case was it obliterated by the mass. In neurofibromas the nerve was either visible in a central position within the mass (two cases) or no longer visible (five cases). A capsule could be detected in 70% of the schwannomas and in 30% of the neurofibromas. In patients with soft tissue masses, MR may contribute to recognition of nerve sheath tumors by showing the nerve of origin and typical signal hyperintensity on T2-weighted images. It can also be helpful in distinguishing between schwannomas and neurofibromas by the location of the nerve of origin and the presence of a capsule.

Adult↗

PubMedDate not supplied

MR imaging of extracranial nerve sheath tumors.

We retrospectively reviewed MR images of 32 histologically proven extracranial nerve sheath tumors (NSTs). There were 23 benign (10 neurofibromas, 13 schwannomas) and 9 malignant NSTs. On T1-weighted images (T1WIs) tumors were isointense or slightly hyperintense to muscle. On T2-weighted images (T2WIs) (11 lesions) and enhanced T1WIs (1 intraspinal lesion), a target pattern with peripheral hyperintense rim and central low intensity was seen in 12 of 23 (52%) benign NSTs (5 of 10 neurofibromas and 7 of 13 schwannomas). This pattern corresponded histologically to peripheral myxomatous tissue and central fibrocollagenous tissue. The pattern was absent in lesions with cystic, hemorrhagic, or necrotic degeneration. These tumors were hyperintense and variably inhomogenous on T2WIs. Malignant NSTs were hyperintense and variably inhomogenous on T2WIs and mimicked benign variably inhomogeneous lesions unless involvement of contiguous structures was visualized. A target pattern was not visible in malignant lesions. Magnetic resonance imaging cannot distinguish schwannomas from neurofibromas, and benign tumors may mimic malignant NSTs when cystic, hemorrhagic, and necrotic degeneration is present. A target pattern may be visualized in some benign NSTs, and evaluation of this sign with assessment of location and growth along nerves may help to avoid confusion with other lesions.

Adult↗

PubMed1988

Epithelial membrane antigen expression by the perineurium of peripheral nerve and in peripheral nerve tumours.

Specimens of normal peripheral nerve and a series of peripheral nerve lesions have been immunostained with three different anti-epithelial membrane antigen (EMA) monoclonal antibodies. Sites of EMA immunoreactivity have been confirmed within perineurial cells of peripheral nerve, noted within the capsule of Schwannomas and palisaded encapsulated neuromas, and also detected with traumatic neuromas and plexiform neurofibromas. No expression was detected within simple neurofibromas, diffuse neurofibromas or within malignant Schwannomas. These sites of EMA expression concur with the suggested involvement of perineurial cells in the formation of the particular lesions. The relationship between EMA expression by the perineurium and the piaarachnoid membrane is discussed.

Antibodies, Monoclonal↗

PubMed1995

MRI of intraspinal nerve sheath tumours presenting with sciatica.

The magnetic resonance imaging (MRI) characteristics of 14 intraspinal nerve sheath tumours (NST) presenting with sciatica were reviewed. The group comprised seven schwannomas, six neurofibromas and one perineuroma. The tumours were either iso- or hypointense with respect to spinal cord on T1-weighted (T1W) images; almost all tumours were hyperintense compared with spinal cord on T2-weighted (T2W) images. The tumours were all detectable on unenhanced T1W images. Nine NST were scanned following Gadolinium-Diethylenetriamine penta acetic acid (DTPA) injection and all showed intense enhancement. This aids differentiation from sequestrated disc fragments. Tumours were more likely to show homogeneous enhancement unless they were recurrent tumours. Rim enhancement occurs more commonly in schwannomas and this can be used to differentiate these from neurofibromas. However, on unenhanced images, schwannomas cannot be distinguished from neurofibromas. Four tumours occurred at T11-T12. There was poor correlation of the site of the lesion with the clinical findings. MRI studies in patients with sciatica should include the lower thoracic region especially if no protruded disc was found in the lumbar region.

Adolescent↗

PubMed1983

Femoral pain of solitary neurofibromatous origin: a report of three cases.

Three patients, each with a solitary neurofibroma in the thigh, are described. The presenting complaint in each case was pain. A neurofibroma of a branch of the femoral nerve was found in two cases and an intraosseous neurofibroma of the femoral shaft was present in the third. An excellent recovery was observed in each of these three patients following surgical excision of the tumour. Attention is drawn to the unduly long interval between the onset of painful symptoms and the achievement of a clinical diagnosis leading to a surgical cure in each instance.

Adult↗

PubMed1992

Peripheral (extracranial) nerve tumors: correlation of MR imaging and histologic findings.

Magnetic resonance (MR) images of 16 peripheral nerve tumors (14 patients) were correlated with histopathologic appearance. Thirteen patients had surgically proved neuro-fibromatosis. There were 10 neurofibromas, four schwannomas, and two neurofibrosarcomas. Seven of the 10 neurofibromas showed a target pattern of increased peripheral signal intensity and decreased central signal intensity on T2-weighted images. This pattern appeared to correspond to a distinctive zonal histologic appearance that was found only in the neurofibromas. This pattern was not seen on MR images of the other peripheral tumors.

Adolescent↗

PubMed1990

Benign nerve sheath tumors: a light microscopic, electron microscopic and immunohistochemical study of 102 cases.

One hundred and two cases of benign nerve sheath tumors (NSTs) were studied with a combined approach using routine light microscopy (LM), immunohistochemistry (IH) for myelin basic protein (MBP) and S-100 protein as well as transmission electron microscopy (TEM) with the aim of obtaining greater insight into the true nature of these neoplasms, and also to establish the importance of IH and TEM in their diagnosis. Myelin basic protein was not identified in any of these tumors, whereas S-100 protein was positive to a variable degree in both schwannomas and neurofibromas. TEM revealed that Schwann cells predominated in tumors which were strongly positive for S-100 protein and appeared as schwannomas by LM. However, neurofibromas showing a variable patchy positivity for S-100 were composed of an admixture of Schwann cells, fibroblast-like cells and intermediate cells considered to be modified Schwann cells. Perineurial cells in typical form were not seen. It is concluded that all NSTs are basically of Schwann cell origin and that the intermediate cells and fibroblast-like cells are variants of Schwann cells. The different morphological appearances and biological behaviour of schwannomas and neurofibromas may be related to some other factors like micro-environment or genetic predisposition. Further, both IH, especially for S-100 protein, and TEM play an important role in establishing their diagnosis.

Cranial Nerve Neoplasms↗

PubMed1986

Mediastinal neurogenic tumours. Early and late results of surgical treatment.

Early and late results of surgery for neurogenic mediastinal tumour were evaluated in 66 cases with a mean follow-up of 12 years. The series comprised 48 neurilemmomas, 8 neurofibromas, 7 ganglioneuromas, and neurinoma, neurofibrosarcoma and ganglioneuroblastoma each in one case. There were two early deaths (3%), one due to peroperative bleeding from the left subclavian artery and the other to acute myocardial infarction. Operative complications arose in 12 cases (18%), the most common being wound infection (3 cases). There were 17 late deaths (26.6%). In the neurilemmoma group, 3 of the 13 late deaths were related to the tumour or its treatment, and both deaths in the neurofibroma group were related to malignant transformation. Recurrence of tumour appeared in 3 of the 48 patients with neurilemmoma and also in the single patient with neurinoma as tumour classification. One neurilemmoma was a dumb-bell tumour, and operation in this case resulted in paraplegia. Malignant transformation appeared in 2 of the 8 neurofibromas 5 and 13 years postoperatively. Because of the risks of malignant degeneration and of recurrence, patients operated on for neurogenic mediastinal tumour should be carefully followed up for many years.

Adolescent↗