Malignant Peripheral Nerve Sheath Tumor, Causes, Signs and Symptoms, Diagnosis and Treatment.

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07/18/23

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Chapters

0:00 Introduction
0;39 symptoms of Malignant Peripheral Nerve Sheath Tumor
1;06 causes of Malignant Peripheral Nerve Sheath Tumor
1;36 diagnosis of
Malignant Peripheral Nerve Sheath Tumor
1;58 risk factors

A malignant peripheral nerve sheath tumor (MPNST) is a form of cancer of the connective tissue surrounding 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%.[2] MPNST with rhabdomyoblastomatous component are called malignant triton tumors.

The first-line treatment is surgical resection with wide margins. Chemotherapy (e.g. high-dose doxorubicin) and often radiotherapy are done as adjuvant and/or neoadjuvant treatment.
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.[3]
Pain or discomfort: numbness, burning, or "pins and needles."[3]
Dizziness and/or loss of balance.[3]

Causes

Soft tissue sarcomas have been linked within families, so it is hypothesized that neurofibrosarcoma may be genetic, although researchers still do not know the exact cause of the disease. Evidence supporting this hypothesis includes loss of heterozygosity on the 17p chromosome. The p53 (a tumor suppressor gene in the normal population) genome on 17p in neurofibrosarcoma patients is mutated, increasing the probability of cancer. The normal p53 gene will regulate cell growth and inhibit any uncontrollable cell growth in the healthy population; since p53 is inactivated in neurofibrosarcoma patients, they are much more susceptible to developing tumors.
Genetics
Autosomal dominant

A malignant peripheral nerve sheath tumor is rare, but is one of the most common frequent soft tissue sarcoma in the pediatrics population. About half of these cases also happen to occur along with neurofibromatosis type 1 (NF-1), which is a genetic mutation on the 17th chromosome which causes tumors along the nervous system. The lifetime risk of patients with NF-1 developing MPNST has been estimated at 8–13%, while those with only MPNST have a 0.001% in the general population.[4] NF-1 and MPNST are categorized as autosomal dominant disorders. This means when one receives an abnormal gene from one of their parents, they will ultimately have that disorder. That person has a 50/50 chance of passing on that gene to their offspring. The pedigree to the right describes this genetic pattern.
Diagnosis

The most conclusive test for a patient with a potential neurofibrosarcoma is a tumor biopsy (taking a sample of cells directly from the tumor itself). MRIs, X-rays, CT scans, and bone scans can aid in locating a tumor and/or possible metastasis.
Classification

Malignant peripheral nerve sheath tumors are a rare type of cancer that arise from the soft tissue that surrounds nerves. They are a type of sarcoma. Most malignant peripheral nerve sheath tumors arise from the nerve plexuses that distribute nerves into the limbs—the brachial and lumbar plexuses—or from nerves as they arise from the trunk.[5]