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Pleomorphic Xanthoastrocytoma (PXA) and Anaplastic Pleomorphic Xanthoastrocytoma (APXA) Diagnosis and Treatment

MRI of a Pleomorphic Xanthoastrocytoma (PXA) in the brain.

Credit: NCI-CONNECT Staff

Pleomorphic xanthoastrocytoma (PXA) and anaplastic pleomorphic xanthoastrocytoma (APXA) are two types of very rare astrocytomas. They are primary central nervous system (CNS) tumors. This means they begin in the brain or spinal cord.

To get an accurate diagnosis, a piece of tumor tissue will be removed during surgery, if possible. A neuropathologist should then review the tumor tissue.

What are the grades of PXA and APXA?

Primary CNS tumors are graded based on the tumor location, tumor type, extent of tumor spread, genetic findings, the patient’s age, and tumor remaining after surgery, if surgery is possible.

These tumors are grouped in two grades based on their characteristics.

  1. Grade II PXAs are low grade tumors. This means the tumor cells grow slowly.
  2. Grade III APXAs are malignant (cancerous). This means they are fast-growing tumors.

What do PXAs and APXAs look like on an MRI?

PXAs often form fluid-filled cysts in a mural nodule, which means a cyst within solid tissue with a dense appearance on MRI.  APXAs may appear similar to PXAs, but the way they look varies and makes it difficult to tell apart from other primary CNS tumors. The diagnosis of PXA or APXA can’t be made by imaging alone because they look the same as glioblastomas and other high-grade brain cancers.

What causes PXAs and APXAs?

Cancer is a genetic disease – that is, cancer is caused by certain changes to genes that control the way our cells function. Genes may be mutated (changed) in many types of cancer, which can increase the growth and spread of cancer cells. The cause of most PXAs and APXAs is not known. People with gene  changes that can be passed down through families such as neurofibromatosis type I and familial melanoma/astrocytoma syndrome, are at increased risk for developing PXAs and APXAs.

Where do PXAs and APXAs form?

PXAs and APXAs usually occur in one of the four lobes of the brain. The temporal lobe is the most common location. Rarely, PXAs and APXAs can form in the cerebellum, brainstem, and spinal cord. PXAs and APXAs are usually located close to the surface of the brain tissue. Scientists believe these tumors arise from cells that grow into glial and nerve cells. PXAs and APXAs can look a variety of ways under the microscope and can be challenging to diagnose, as they share characteristics with other primary brain tumors. Review by an expert neuropathologist is recommended to confirm this diagnosis. Molecular testing will often reveal a BRAF gene change in these tumors.

Do PXAs and APXAs spread? 

PXAs are slow-growing tumors that usually don’t spread. APXAs are fast-growing tumors that usually invade brain tissue in the lobe of the brain where they started. It’s rare for APXAs and PXAs to spread to other areas of the CNS. There are no reported cases of spread outside of the CNS.

What are symptoms of a PXA or APXA?

Symptoms related to PXAs and APXAs depend on the tumor’s location. Here are some possible symptoms that can occur.

PXA or APXA Symptoms

People with PXAs may have:

  • Seizures
  • Epilepsy
  • Chronic headaches

People with APXAs may have:

  • Seizures
  • Weakness
  • Numbness
  • Speech and language changes

Who is diagnosed with PXAs and APXAs?

PXAs and APXAs can occur at any age, but tend to happen in young adulthood, and occur slightly more often in males than females. PXAs and APXAs are more common in people of African descent.  An estimated 1,081 people are living with this tumor in the United States.

What is the prognosis of PXAs and APXAs?

The likely outcome of the disease or chance of recovery is called prognosis.

PXA and APXA Prognosis

The relative 5-year survival rate for PXA and APXA is 76.2% but know that many factors can affect prognosis. This includes the tumor grade and type, traits of the cancer, the person’s age and health when diagnosed, and how they respond to treatment. If you want to understand your prognosis, talk to your doctor.

What are treatment options for PXAs and APXAs?

The first treatment for a PXA and APXA is surgery, if possible. The goal of surgery is to obtain tissue to determine the tumor type and to remove as much tumor as possible without causing more symptoms for the person. PXAs can often be treated by surgery alone.

If they come back after surgery, there is no standard treatment for PXAs and APXAs. Possible treatments at this time may include radiation, chemotherapy, targeted therapies, or clinical trials. If a BRAF change is present, clinical trials using a drug to target that may also be an option. Treatments are decided by the patient’s healthcare team based on the patient’s age, remaining tumor after surgery, tumor type, and tumor location.

Open Clinical Studies for PXAs and APXAs

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Find doctors and nurses with experience treating this tumor.

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