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At least 487 records · Page 27Linked to original sources
PubMed2004

In vitro studies of pigment epithelium-derived factor in human Schwann cells after treatment with axolemma-enriched fraction.

Pigment epithelium-derived factor (PEDF) is a multifunctional protein with known anti-angiogenic and trophic properties, capable of promoting the survival and growth of Schwann cells (SC). Normal rat SCs and ganglioneuroma-derived human SCs secrete PEDF. The ability of normal SC to secrete a number of trophic factors is controlled by axonal contact. Normal human Schwann cells (HSC) and malignant peripheral nerve sheath tumors (MPNST) cell lines synthesize and secrete PEDF as determined by reverse transcription PCR analysis for PEDF mRNA, immunocytochemistry, and Western blot analysis for PEDF protein. Two MPNST cell lines secreted higher levels of PEDF than did HSC. A 90.3% decrease in PEDF mRNA and a 29.3% decrease in secreted PEDF were observed after treatment of HSC with axolemma-enriched fraction (AEF, 100 microg/ml), a neuronal membrane fraction of the axonal plasma membrane used with cultured SC to mimic axonal contact in vitro. PEDF levels remained unchanged, however, in MPNST-derived SC conditioned media under the same treatment paradigm. These results suggest that MPNST SC lose the ability to downregulate PEDF upon axonal contact, which is characteristic of HSC. The elevated PEDF levels expressed by MPNST cell lines may serve to promote their proliferation and survival.

Adult↗
PubMed1984

Malignant mesenchymoma of median nerve: combined nerve sheath sarcoma and liposarcoma.

A malignant mesenchymoma consisting of nerve sheath sarcoma and liposarcoma occurred in the right median nerve of a 29-year-old man who did not have stigmata of von Recklinghausen neurofibromatosis. It produced pain at the affected part, referred pain to the palm, and weakness of muscles supplied by branches of this nerve. The tumor was first excised 1 month after its initial manifestation, but recurred twice and eventually metastasized to the lung within 19 months. It is suggested that aberrant differentiation of the mesenchymal component of the neural crest, the ectomesenchymal structure, has created this combined sarcoma of nerve sheath and liposarcoma, forming a malignant mesenchymoma.

Adipose Tissue↗
PubMed2003

Imaging tumours of the brachial plexus.

Tumours of the brachial plexus are rare lesions and may be classified as benign or malignant. Within each of these groups, they are further subdivided into those that are neurogenic in origin (schwannoma, neurofibroma and malignant peripheral nerve sheath tumour) and those that are non-neurogenic. Careful pre-operative diagnosis and staging is essential to the successful management of these lesions. Benign neurogenic tumours are well characterized with pre-operative MRI, appearing as well-defined, oval soft-tissue masses, which are typically isointense on T1-weighted images and show the "target sign" on T2-weighted images. Differentiation between schwannoma and neurofibroma can often be made by assessing the relationship of the lesion to the nerve of origin. Many benign non-neurogenic tumours, such as lipoma and fibromatosis, are also well characterized by MRI. This article reviews the imaging features of brachial plexus tumours, with particular emphasis on the value of MRI in differential diagnosis.

Brachial Plexus↗
PubMed2003

Sonographic evaluation of brachial plexus pathology.

Pre-operative US examinations of the brachial plexus were performed with the purpose of exploring the potential of this technique in recognizing lesions in the region and defining their sonographic morphology, site, extent, and relations to adjacent anatomic structures, and comparing them to the surgical findings to obtain maximal confirmation. Twenty-eight patients with clinical, electro-conductive, and imaging findings suggestive of brachial plexus pathology were included in this study. There were four main etiology groups: post-traumatic brachial plexopathies; primary tumors (benign and malignant); secondary tumors; and post irradiation injuries. Twenty-one of the 28 patients underwent surgery. Advanced imaging (mostly MRI) served as an alternative gold standard for confirmation of the findings in the non-surgically treated group of patients. The US examinations were performed with conventional US units operating at 5- to 10-MHz frequencies. The nerves were initially localized at the level of the vertebral foramina and then were followed longitudinally and axially down to the axillary region. Abnormal US findings were detected in 20 of 28 patients. Disruption of nerve continuity and focal scar tissue masses were the principal findings in the post-traumatic cases. Focal masses within a nerve or adjacent to it and diffuse thickening of the nerve were the findings in primary and secondary tumors. Post-irradiation changes presented as nerve thickening. Color Doppler was useful in detecting internal vascularization within masses and relation of a mass to adjacent vessels. The eight sonographically negative cases consisted either of traumatic neuromas smaller than 12 mm in size and located in relatively small branches of posterior location or due to fibrotic changes of diffuse nature. Sonography succeeded in depicting a spectrum of lesions of traumatic, neoplastic, and inflammatory nature in the brachial plexus. It provided useful information regarding the lesion site, extent, and anatomic relationships; thus, the principal aims of the study were therefore met. Once the technique of examination is mastered, sonography should be recommended as part of the pre-operative evaluation process post-ganglionic brachial plexus pathology. Most disadvantages are related to the restricted field of view and inability to overcome bonny obstacles particularly in evaluating pre-ganglionic region. As sonography is frequently employed for investigation of the supraclavicular region, awareness of the radiologist to the findings described may enable the early recognition of pathologies involving or threatening to involve the brachial plexus.

Adult↗
PubMed2004

Mediastinal neurofibroma originating from the left intrathoracic phrenic nerve: report of a case.

We report a case of mediastinal neurofibroma originating from the left phrenic nerve in a 42-year-old woman who was referred to us after a routine chest X-ray showed a smooth, round abnormal shadow in the left middle lung field adjacent to the heart. We resected a 25 x 20 x 20-mm tumor by video-assisted thoracic surgery. Histopathological examination confirmed that the lesion was a mediastinal neurofibroma originating from the left phrenic nerve without von Recklinghausen's disease. Neurogenic mediastinal tumors originating from the phrenic nerve are very rare, and to the best of our knowledge, no other case of a mediastinal neurofibroma originating from the phrenic nerve in a patient without von Recklinghausen's disease has ever been reported.

Adult↗
PubMed1999

Ependymoma of the cauda equina.

Myxopapillary ependymomas are benign tumours which occasionally metastasize along cerebrospinal fluid pathways. Extraneural metastases of spinal ependymomas, however, are very rare, even more so when situated in the pleura. We report the case of a 67 year old woman presenting with shortness of breath after recurrent myxopapillary ependymomas of the cauda equina. Chest X-ray showed multiple pleural lesions diagnosed as metastases of a myxopapillary ependymoma. The MIB-1 proliferation index was 3.1% for the initial spinal tumour, 14.2% for the first and 11.2% for the second recurrence while 12.0% for the pleural metastasis.

Aged↗
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↗
PubMed2005

Recurrent retroperitoneal malignant nerve sheath tumor associated with neurofibromatosis type 1 responding to carboplatin and etoposide combined chemotherapy.

A 25-year-old man was referred to our hospital with left flank pain, and computed tomography (CT) and magnetic resonance imaging (MRI) revealed large retroperitoneal masses. Physical examination revealed many café-au-lait spots and superficial neurofibromas, and a diagnosis of neurofibromatosis type 1 (von Recklinghausen's disease) was made. The tumor was resected, and the pathological diagnosis was malignant peripheral nerve sheath tumor (MPNST). Six months after the operation, lung metastases were detected. Surgical resection was incomplete, as there were too many lesions. He received four courses of chemotherapy with carboplatin and etoposide, and the metastatic lung lesions were markedly decreased. After chemotherapy, complete resection of the remaining lung lesions was performed, and there has been no recurrence to date.

Adult↗
PubMed2006

Histopathology and clinical outcome of NF1-associated vs. sporadic malignant peripheral nerve sheath tumors.

The differences in the clinical course and histopathology of sporadic and neurofibromatosis type 1 (NF1)-associated malignant peripheral nerve sheath tumors (MPNST) were investigated retrospectively. The collective comprised 38 NF1 patients and 14 sporadic patients. NF1 patients were significantly younger at diagnosis (p<0.001) and had a significantly shorter survival time than sporadic patients (median survival 17 months vs. 42 months, Breslow p<0.05). The time interval to local recurrence and metastatic spread was also significantly shorter in NF1 patients (9.4 months vs. 30.0 months, p<0.01; 9.1 months vs. 33.2 months, p<0.001, respectively). In patients with the original histopathological data available (22 NF1 patients, 14 sporadic cases), NF1-associated MPNST showed a significantly higher cellularity compared to sporadic tumors (p<0.001) whereas sporadic MPNST featured a significantly higher pleomorphism (p<0.01). Most importantly, while histopathological variables correlated with French Fédération Nationale des Centres de Lutte Contre le Cancer grading in sporadic MPNST, this was not the case for NF1-associated tumors. The differences between NF1-associated and sporadic MPNST in regard to the clinical course and histopathology may reflect some fundamental differences in biology and pathomechanism of the two tumor groups. Our findings indicate the necessity for a separate grading scheme which takes into account the genetic background in NF1 patients.

Adolescent↗
PubMed1991

Schwannoma of the brachial plexus mimicking an apical lung tumor.

Primary tumors of the brachial plexus are unusual. We describe a patient with a large schwannoma of the lower trunk of the brachial plexus that had the radiologic appearance of an apical lung mass. Use of a posterior subscapular approach as well as intraoperative nerve action potential recording permitted resection with spared function.

Adult↗