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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%. [2]
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. [1] They are categorized as either benign or malignant peripheral nerve sheath tumors. [2] [3]
The peripheral PNET (pPNET) is now thought to be virtually identical to Ewing sarcoma: "Current evidence indicates that both Ewing's sarcoma and PNET have a similar neural phenotype and, because they share an identical chromosome translocation, they should be viewed as the same tumor, differing only in their degree of neural differentiation.
In perineural invasion, cancer cells proliferate around peripheral nerves and eventually invade them. Cancer cells migrate in response to different mediators released by autonomic and sensory fibers. Tumor cells secrete CCL2 and CSF-1 to accumulate endoneurial macrophages and, at the same time, release factors that stimulate perineural invasion.
Secondary CNS tumors, or metastatic tumors, occur when cancer cells spread to the brain or spinal cord from a primary tumor in another part of the body. These tumors are more common than primary CNS tumors in adults and often originate from cancers of the lung , breast , skin , kidney , or colon .
Malignant melanotic nerve sheath tumor (previously known as melanotic schwannoma) is a rare aggressive peripheral nerve sheath tumor that typically develops in conjunction with spinal or visceral autonomic nerves, consisting uniformly of Schwann cells displaying melanocytic differentiation.
The name "synovial sarcoma" was coined early in the 20th century, as some researchers thought that the microscopic similarity of some tumors to synovium, and its propensity to arise adjacent to joints, indicated a synovial origin; however, the actual cells from which the tumor develops are unknown and not necessarily synovial. [3]
Because of this risk, radiation treatment for cancer is now planned to ensure that the maximum dosage of radiation is delivered to diseased tissue while surrounding healthy tissue is protected as much as possible. [5] Kaposi sarcoma, a rare cancer of the cells that line blood vessels in the skin and mucous membranes, is caused by human ...