1/41. Molecular analysis of malignant triton tumors.Triton tumors are rare variants of malignant peripheral nerve sheath tumor (MPNST) with muscle differentiation, often seen in patients with neurofibromatosis 1 (NF1). Individuals affected with NF1 harbor mutations in the NF1 tumor suppressor gene and develop neurofibromas and MPNSTs. The NF1 gene is expressed in schwann cells and its expression is lost in schwannian neoplasms, suggesting a role in malignant development. Separately, there is evidence that p53 suppressor gene mutations are involved in MPNSTs. To determine the role of the NF1 and p53 genes in the development of the malignant Triton tumor we examined 2 such tumors, 1 from a 3-year-old boy without clinical manifestations of NF1 and another from a 24-year-old man with NF1. Histological analysis of these tumors showed both neural and muscle differentiation with S-100 and desmin immunoreactivity, respectively. Reverse transcribed rna polymerase chain reaction (RT-PCR) of NF1 mRNA showed NF1 expression in the sporadic tumor. Strong nuclear immunoreactivity for p53 was observed throughout the malignant population in both tumors. This was confirmed by loss of heterozygosity for p53 in the non-NF1 patient, suggesting that p53 is involved in both hereditary and sporadic Triton tumors. The finding of preserved NF1 gene expression in the non-NF1-related Triton tumor suggests that different genetic events predispose to the development of this rare neoplasm in sporadic cases.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
2/41. Intraspinal primitive neuroectodermal tumour: report of two cases and review of the literature.Two patients with primary intraspinal primitive neuroectodermal tumour are presented. In a 32-year-old man, the tumour evolved intradurally from a sacral nerve root. Despite repeated surgery and radiochemotherapy, the patient suffered multiple intraspinal tumour relapses and intracranial seedings, and died 29 months after the first diagnosis. In a 17-year-old male adolescent, the tumour was located in the lumbar epidural space, extending into the paraspinal muscles. Following resection and radiochemotherapy, the patient is free from disease 23 months after the initial presentation. The clinical, radiological, histopathological and cytogenetic findings of both patients are presented and the relevant literature is reviewed. Particular attention is given to the histogenetic relationship between peripheral primitive neuroectodermal tumour and Ewing's sarcoma.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
3/41. Solitary sciatic nerve lymphoma as an initial manifestation of diffuse neurolymphomatosis. Case report and review of the literature.Solitary peripheral nerve lymphomas are exceedingly rare primary manifestations of diffuse peripheral nervous system or central nervous system (CNS) lymphomatosis. A 52-year-old man presented with progressive weakness in gastrocnemius and anterior tibial muscle function, which was associated with radiating pain in the right leg. magnetic resonance imaging studies revealed a solitary fusiform tumor, extending from the sciatic nerve, at the level of the lesser trochanter of the femur, into the posterior tibial nerve below the popliteal fossa. Intraoperative gross examination found that the tumor diffusely expanded the nerve, but did not extend from or into surrounding muscle or tendons. The final histological diagnosis was a solitary extranodal lymphoma (Burkittlike high-grade B-cell lymphoma). Postoperative staging did not reveal evidence of lymphomatous involvement of other organs, but additional chemo- and radiotherapies were administered. Four months after the surgical biopsy, the patient presented with a right facial nerve palsy. The results of cytological examination of cerebrospinal fluid were positive for the presence of atypical lymphocytes, which was consistent with apparently progressive neurolymphomatosis; however, the results of radiological studies were negative for systemic progression. The patient underwent intrathecal chemotherapy followed by systemic myelosuppressive chemotherapy with bone marrow rescue, but died of respiratory failure while still receiving treatment. Postmortem examination revealed extensive lymphomatosis in the peripheral nerves and spinal nerve roots without evidence of cranial nerve, CNS, or other organ system involvement. The aggressive biological characteristics of these tumors, their management, and pertinent literature are reviewed.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
4/41. An unusual schwannoma of the median nerve: effects on the motor branch.An unusual case of a schwannoma of the median nerve is presented where pressure due to the tumour on the motor branch to the thenar muscles caused weakness and wasting of the abductor pollicis brevis muscle, a previously unreported phenomenon. The patient achieved a full functional recovery after enucleation, which is also unusual considering the patient's age. Aspects of schwannoma biology, differential diagnosis, investigation and treatment are discussed.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
5/41. sciatica due to malignant nerve sheath tumour of sciatic nerve in the thigh.Malignant peripheral nerve sheath tumour (MPNST) is a rare malignant neoplasm arising from the supportive non-neural component of the peripheral nerves. An unusual case of pain and weakness of the foot and calf muscles due to a giant MPNST of the sciatic nerve in the posterior compartment of the thigh is presented. The patient was already investigated as a case of sciatica due to a lumbar disc disease with a negative magnetic resonance imaging and then unsuccessfully operated elsewhere twice, with a misdiagnosis of tarsal tunnel syndrome. Neurosurgical referral prompted a diagnostic magnetic resonance study of the thigh, revealing the lesion, which was completely excised microsurgically with total relief in the pain and partial improvement in the weakness and sensations in the sole of the foot.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
6/41. neuroma transposition and intramuscular implantation using the Mitek "soft-tissue anchor": a new technique.The authors describe a new technique for intramuscular implantation of a nerve ending after peripheral neuroma excision. Sixteen peripheral neuromas in 10 patients were excised and then implanted into muscle tissue using the Mitek anchor. The positions of the anchors were documented by immediate anteroposterior and lateral radiographs. These views were repeated at 2 months to assess any migration. All patients had resolution of the symptoms related to their neuromas. No substantial migration was noted in any of the patients. The Mitek anchor can be used as a "soft-tissue" anchor to position a nerve ending reliably at a precise depth and tension in muscle tissue with minimal trauma.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
7/41. Amyloidoma of the brachial plexus.BACKGROUND: Amyloidomas of the peripheral nervous system are rare lesions. Most commonly, they involve the gasserian ganglion and the branches of the fifth cranial nerve. No association with systemic amyloidosis has been reported. CASE DESCRIPTION: We describe an amyloidoma of the lower trunk of the right brachial plexus. At the age of 34 years, this 71-year-old female had undergone radical right mastectomy for breast cancer with axillary lymph node dissection followed by radiotherapy. On admission, she presented with burning pain to the right hand and mild motor deficit to the ulnar-innervated intrinsic hand muscles. A palpable lesion was found in the supraclavicular region. On surgical inspection, the lesion appeared to originate from the lower trunk of the right brachial plexus. The middle and upper trunks were dislocated. Histologically, fibrous connective tissue embedded small nerve bundles featuring perineurial and endoneurial fibrosis as well as amyloid. Amyloid featured immunoreactivity for both lambda and kappa chains. DISCUSSION: Localized amyloidoma of brachial plexus has never been reported. Because of compressive rather than infiltrative growth of the present lesion, a conservative surgery was achieved. Our immunohistochemical findings indicated that peripheral nerve amyloidomas are not, by definition, monoclonal in nature.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
8/41. Angiotropic lymphoma (intravascular large cell lymphoma) presenting with cauda equina syndrome.A 50-year-old man developed cauda equina syndrome of unknown etiology that was stable for 20 months. Two months prior to sudden death, he experienced new back pain, confusion, seizures, and multiple cranial nerve palsies. Neuropathologic examination revealed angiotropic lymphoma without parenchymal involvement or infarcts in the brain, spinal cord, and muscle. In addition, nerve roots in the cauda equina contained angiotropic lymphoma and infarcts of various ages. Angiotropic lymphoma should be considered as a cause of cauda equina syndrome and of disorders that affect the central and peripheral nervous systems concurrently.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
9/41. Non-malignant perineural spread of epithelial tissue in the orofacial region.A 48 year-old male had two operations because of severe neuralgic pains in the region of the right infraorbital nerve. The first operative specimen consisted of connective tissue, striated muscle fibers and two myelinated nerve bundles, surrounded by a ring of well differentiated squamous epithelium. Initially the lesion was assumed to show perineural spread of cancer in this region. As the pain was not alleviated, a second operation was performed. The framework of the second specimen also consisted of connective tissue and muscle. It contained in addition an atheromalike cyst and some nerve bundles, ensheathed by well differentiated epithelial cells partly in a ring-, partly in a horseshoe-like pattern. The perineural epithelial sheaths could be traced to a rupture of the cyst, and to benign proliferation of its epithelial lining in the connective tissue and along the nerve bundles. Following the second operation the patient was relieved of his complaints. During the last five years he had repeated control examinations but no sign of malignant disease could be found; his state of health was perfect. Our finding of benign perineural spread of squamous epithelium has not been described previously. The nature of the so-called perineural lymph spaces is also discussed.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
10/41. Plexiform schwannoma of the forearm.We report a case of plexiform schwannoma located in the flexor muscles of the forearm in the absence of other signs of neurofibromatosis or schwannomatosis. Magnetic resonance examination revealed a multinodular irregular inhomogeneous mass. Some nodules displayed a peripheral, high intensity rim and a central low intensity (target sign) on T2-weighted images. Pre-operative diagnosis of the rare plexiform schwannoma may be possible with careful imaging examination for the target sign.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
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