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PNST
A nerve sheath tumor is a type of tumor of the nervous system ( nervous system neoplasm) which is made up primarily of the myelin surrounding nerves. Nerve sheath tumors can be benign or malignant, and may affect both the peripheral and central nervous systems. There are three main types of nerve sheath tumors: schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors. Classification of nerve sheath tumors Spinal nerve sheath tumors Spinal nerve sheath tumors are typically intradural, meaning that they arise inside the dura mater surrounding the spinal cord (thecal sac), but may also be found in other areas of the spine. Spinal nerve sheath tumors generally arise as single lesions. Presence of multiple lesions is associated with genetic conditions including neurofibromatosis type 1, neurofibromatosis type 2, and Schwannomatosis. Most spinal schwannomas are intradural-extramedullary, growing inside the thecal sac, but outside the spinal cord itself. Intradura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malignant Peripheral Nerve Sheath Tumor
A malignant peripheral nerve sheath tumor (MPNST) is a form of cancer of the connective tissue surrounding peripheral nerves. Given its origin and behavior it is classified as a sarcoma. About half the cases are diagnosed in people with neurofibromatosis; the lifetime risk for an MPNST in patients with neurofibromatosis type 1 is 8–13%. MPNST with rhabdomyoblastomatous component are called malignant triton tumors. The first-line treatment is surgical resection with wide margins. Chemotherapy and often radiotherapy are done as adjuvant and/or neoadjuvant treatment depending upon various risk factors. Signs and symptoms Symptoms may include: * Swelling in the extremities (arms or legs), also called peripheral edema; the swelling often is painless. * Difficulty in moving the extremity that has the tumor, including a limp. * Soreness localized to the area of the tumor or in the extremity. * Neurological symptoms. * Pain or discomfort: numbness, burning, or "pins and need ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Nerve Tumor
Peripheral nerve tumors, also called tumors of peripheral nerves or tumors of the peripheral nervous system, are a diverse category with a range of morphological characteristics and biological potential. They are categorized as either benign or malignant peripheral nerve sheath tumors. Description They vary from benign (soft tissue perineurioma and schwannoma) that can be completely removed to benign (plexiform neurofibroma) that may be locally aggressive to extremely malignant ( malignant peripheral nerve sheath tumors PNST. New and more precisely defined entities include malignant melanotic nerve sheath tumor (formerly known as melanotic schwannoma) and hybrid nerve sheath tumors. The majority of peripheral nerve tumors are benign tumors of the nerve sheath (usually schwannomas); on rare occasions, they are metastatic tumors or originate from the nerve cells. Most peripheral nerve tumors occur for unknown reasons. Some, including schwannomatosis and neurofibromatosis (types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nervous System Neoplasm
A nervous system tumor is a tumor that arises within the nervous system, either the central nervous system (CNS) or the peripheral nervous system (PNS). Nervous system primary tumors include various types of brain tumor and spinal tumors, such as gliomas, and meningiomas (of the CNS), and schwannomas (of the PNS) and can be either benign or malignant. There are over 120 types of brain and spinal cord tumors. In the CNS a tumor may be a malignant secondary tumor having metastasised (spread from a primary site in the body). Secondary tumors are more common in adults. Treatment and prognosis depend on factors such as the type of tumor, location, and molecular characteristics. Types Primary tumors can affect either the peripheral nervous system (PNS) or the central nervous system (CNS). They may be either benign or malignant. A nerve sheath tumor may be found in both the CNS and PNS. There are over 120 types of brain and spinal cord tumor. A secondary tumor may be found in the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurofibromatosis Type I
Neurofibromatosis type I (NF-1), or von Recklinghausen syndrome, is a complex multi-system neurocutaneous disorder caused by a subset of genetic mutations at the neurofibromin 1 (''NF1'') locus. Other conditions associated with mutation of the ''NF1'' gene include Watson syndrome. NF-1 is a gene on chromosome 17 that is responsible for production of a protein (neurofibromin) which is needed for normal function in many human cell types. causes tumors along the nervous system that can grow anywhere on the body. is one of the most common genetic disorders and is not limited to any person's race or sex. NF-1 is an autosomal dominant disorder, which means that mutation or deletion of one copy (or allele) of the is sufficient for the development of , although presentation varies widely and is often different even between relatives affected by . , there are at least 100,000 people in the U.S. and about 25,000 people in the UK who have been diagnosed with NF. Common symptoms of inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurofibroma
A neurofibroma is a benign nerve-sheath tumor in the peripheral nervous system. In 90% of cases, they are found as stand-alone tumors (solitary neurofibroma, solitary nerve sheath tumor or sporadic neurofibroma), while the remainder are found in persons with neurofibromatosis type I (NF1), an autosomal-dominant genetically inherited disease. They can result in a range of symptoms from physical disfiguration and pain to cognitive disability. Neurofibromas arise from nonmyelinating-type Schwann cells that exhibit biallelic inactivation of the ''NF1'' gene that codes for the protein neurofibromin. This protein is responsible for regulating the RAS-mediated cell growth signaling pathway. In contrast to schwannomas, another type of tumor arising from Schwann cells, neurofibromas incorporate many additional types of cells and structural elements in addition to Schwann cells, making it difficult to identify and understand all the mechanisms through which they originate and develop. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schwannoma
A schwannoma (or neurilemmoma) is a usually benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves. Schwannomas are homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow-growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant, degenerating into a form of cancer known as neurofibrosarcoma. These masses are generally contained within a capsule, so surgical removal is often successful. Schwannomas can be associated with neurofibromatosis type II, which may be due to a loss-of-function mutation in the protein merlin. They are universally S-100 positive, which is a marker for cells of neural crest cell origin. Schwannomas of the head and neck are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myelin
Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon. Myelin ensheaths part of an axon known as an internodal segment, in multiple myelin layers of a tightly regulated internodal length. The ensheathed segments are separated at regular short unmyelinated intervals, called nodes of Ranvier. Each node of Ranvier is around one micrometre long. Nodes of Ranvier enable a much faster rate of conduction known as saltatory conduction where the action potential recharges at each node to jump over to the next node, and so on till it reaches the axon terminal. At the terminal the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuro-oncology
Neuro-oncology is the study of brain and spinal cord neoplasms, many of which are (at least eventually) very dangerous and life-threatening (astrocytoma, glioma, glioblastoma multiforme, ependymoma, pontine glioma, and brain stem tumors are among the many examples of these). Among the malignant brain cancers, gliomas of the brainstem and pons, glioblastoma multiforme, and high-grade (highly anaplastic) astrocytoma/oligodendroglioma are among the worst. In these cases, untreated survival usually amounts to only a few months, and survival with current radiation and chemotherapy treatments may extend that time from around a year to a year and a half, possibly two or more, depending on the patient's condition, immune function, treatments used, and the specific type of malignant brain neoplasm. Surgery may in some cases be curative, but, as a general rule, malignant brain cancers tend to regenerate and emerge from remission easily, especially highly malignant cases. In such cases, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereotactic Body Radiotherapy
Stereotactic surgery is a minimally invasive form of surgical intervention that makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radiosurgery (SRS), etc. In theory, any organ system inside the body can be subjected to stereotactic surgery. However, difficulties in setting up a reliable frame of reference (such as bone landmarks, which bear a constant spatial relation to soft tissues) mean that its applications have been, traditionally and until recently, limited to brain surgery. Besides the brain, biopsy and surgery of the breast are done routinely to locate, sample (biopsy), and remove tissue. Plain X-ray images (radiographic mammography), computed tomography, and magnetic resonance imaging can be used to guide the procedure. Another accepted form of "stereotactic" is "stereotaxic". The word roots are '' stereo-'', a prefix derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radicular Pain
Radicular pain, or radiculitis (from the ), is pain "radiated" along the dermatome (sensory distribution) of a nerve due to inflammation or other irritation of the nerve root (radiculopathy) at its connection to the spinal column. A common form of radiculitis is sciatica – radicular pain that radiates along the sciatic nerve from the lower spine to the lower back, gluteal muscles, back of the upper thigh, calf, and foot as often secondary to nerve root irritation from a spinal disc herniation or from osteophytes in the lumbar region of the spine. Radiculitis indicates inflammation of the spinal nerve root, which may lead to pain in that nerve's distribution without weakness – as opposed to radiculopathy. When the radiating pain is associated with numbness or weakness, the diagnosis is radiculopathy if the lesion is at the nerve root, or myelopathy if at the spinal cord itself. See also * Intervertebral disc * Spinal disc herniation * Arachnoiditis Arachnoiditis is an in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve Conduction Study
A nerve conduction study (NCS) is a medical test, medical diagnostic test commonly used to evaluate the function, especially the ability of action potential, electrical conduction, of the motor nerve, motor and sensory nerves of the human body. These tests may be performed by Specialty (medicine), medical specialists such as clinical neurophysiology, clinical neurophysiologists, physical therapy, physical therapists, physiatry, physiatrists (physical medicine and rehabilitation physicians), and neurology, neurologists who subspecialize in electrodiagnostic medicine. In the United States, neurologists and physiatrists receive training in electrodiagnostic medicine (performing needle electromyography (EMG and NCSs) as part of residency training and, in some cases, acquire additional expertise during a fellowship in clinical neurophysiology, electrodiagnostic medicine, or neuromuscular medicine. Outside the US, clinical neurophysiologists learn needle EMG and NCS testing. Purpose and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In computer science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction. Clinical uses EMG testing has a varie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
