Malignant Peripheral Nerve Sheath Tumors (MPNST) are a very specific form of cancer. They make up somewhere between 5% and 10% of all diagnosis of soft tissue sarcomas and can occur in relation to neurofibromatosis-1 (NF1) or completely on their own. If you have been diagnosed with MPNST, the following information is important to know.
The Effects of MPNST
As its formal name suggests, MPNST is a form of cancer that attacks peripheral nerves in the body. Sometimes, it goes after Schwann cells, fibroblasts, perineural cells or other types related to the nerve sheath.
MPNST is a type of sarcoma, meaning it causes a malignant tumor to form in the body, usually on connective tissue, but also on other kinds of nonepithelial tissue too.
Like most forms of sarcoma, MPNST generally occurs in adulthood. Patients tend to be somewhere between 20 and 50 years old. However, roughly 10% to 20% of the time, this cancer attacks people under 20. Fortunately, cases of children getting it before their first year are incredibly rare.
The first sign of MPNST is a large, palpable mass on the body. Again, this is typical for cases of sarcoma. Also consistent with this category of cancer is that the palpable mass generally causes some type of pain.
As we mentioned at the beginning, MPNST often happens in conjunction with NF1. When it does, the tumor tends to grow much quicker and should be seen as a greater risk for malignant deterioration of neurofibroma.
However, it can also arise from peripheral nerves, in which case, it could result in a number of different clinical patterns, including paresthesias, radicular pain, and motor weakness. Usually, MPNSTs occur alongside large peripheral nerves like the brachial plexus, sciatic nerve, or sacral plexus.
No matter where they form, these tumors tend to be deep-seated, involving the proximal and lower extremities. The trunk is often involved too. Oddly enough, when they grow in cases involving the NF1, MPNSTs generally don’t become malignant, thus there is no need to closely monitor them (unless there are multiple cases arising in the same area).
Undergoing an MRI
When a patient visits their doctor and it appears an MPNST is at work (more than likely, the doctor will simply know some type of sarcoma is most likely present), they will probably use an MRI to take a look. Diagnosis will never be made without some type of view into the body, though a CT scan or x-ray may be done too.
No matter where the source of pain is coming from, the doctor will also take a look at the chest to ensure the lungs are clear. The bones of the pleura will be looked at as well, as this is another likely spot for MPNSTs to form. This is why CT scans are almost always used, though bone scans may be done as well, in order to find any metastatic bone disease that could have grown.
Most doctors will address MPNST with staging, beginning with a biopsy. This is just about the only way to discover the grade of the tumor being dealt with. Fine needle aspirations (FNAs) are the method of choice for acquiring individual cells that will then be put through cytologic review.
After the doctor is able to make this assessment, they can proceed with adjuvant treatment and further planning. Usually, radiation or chemotherapy will be involved.
If you believe you are displaying any of the signs of Malignant Peripheral Nerve Sheath Tumors (MPNST), get to a doctor right away. As with any form of cancer, the sooner you seek medical attention, the better your chances are of surviving.