All The Information You Need Concerning
Leiomyosarcoma And Power Morcellators

Undifferentiated Pleomorph

Undifferentiated pleomorphic sarcoma (also known as malignant fibrous histiocytoma) is a type of cancer that usually affects the arms and legs. The following will provide you with a useful primer in understanding important topics regarding it.

Causes of Undifferentiated Pleomorph

Unfortunately, no one knows for sure what caused undifferentiated pleomorphic sarcoma. Of course, this tends to be the case with most forms of this type of cancer. What originally causes the proliferation of cells that eventually become cancerous is a mystery. That being said, there are a number of risk factors that scientists have identified. They are:

  • Genetic: This doesn’t mean that undifferentiated pleomorphic sarcoma is inherited, rather that genetic abnormalities could be causing the cancer.
  • Radiation: By far the most established of the risk factors is radiation therapy when used to address soft tissue sarcomas. Those who receive radiation to address their cancer are at risk of developing undifferentiated pleomorphic sarcoma.
  • Chemicals: Another risk factor pending proof is certain chemicals. Doctors believe that exposure to things like arsenic, wood preservatives (thanks to their chlorophenols), vinyl chloride and certain herbicides may trigger the growth of undifferentiated pleomorphic sarcoma.


There are a couple major problems that can make a diagnosis of undifferentiated pleomorphic sarcoma difficult. The first is that it goes after soft tissue. Being elastic and flexible, soft tissue cancers like this one can grow for a long time before the tumor is ever discovered.

The second problem is that these tumors are usually painless as well. Sometimes, this helps it avoid discovery. Other times, people won’t take its presence seriously until its growth has matured. Unless an undifferentiated pleomorphic sarcoma tumor pinches a muscle or nerve, the growth usually doesn’t bring about a physical response.

Unfortunately, this could mean that, by the time anyone discovers it, the cancer has already spread. Usually, this means it has metastasized to the lungs, but it could end up causing bone cancer too.

Nonetheless, no doctor is going to diagnose something like undifferentiated pleomorphic sarcoma just by looking at it. Instead, they may use one of a number of tools to make their diagnosis. Most commonly, these are:

  • Imaging tests: In order to get a better look at the tumor, doctors may use CT scans, x-rays and MRIs. They make it easy to see the size of the tumor, its shape and whether or not it’s spread.
  • Biopsy: Whether with a special needle or through surgery, tissue from a tumor can be removed and put under a microscope for closer examination. This is often enough for a doctor to decide if a patient has a cancerous tumor.
  • Blood tests: One preliminary test doctors will often do is checking a patient’s blood count. They’ll examine white and red blood cell numbers as well as platelet counts. Doctors can also test for enzymes and/or hormones indicative of cancer.


Like most sarcomas, the best way to treat undifferentiated pleomorphic sarcoma is to remove the tumor through surgery. If there are remaining cancer cells in the body, then radiation or chemotherapy is generally used to address it.

In some cases, though, the tumor may have spread to the point that surgery isn’t an option. As undifferentiated pleomorphic sarcoma usually affects the limbs, surgeons will do their best to remove the tumor while leaving as much of the arm or leg intact. When this isn’t possible, though, it may become necessary to actually amputate the limb, especially if the sarcoma has spread and become bone cancer.

The good news is that there is a high survival rate for those whose undifferentiated pleomorphic sarcomas are caught and addressed early. Once the cancer has advanced, there’s usually a five-year survival rate.