NCI-CONNECT Rare Brain & Spine Tumor Network
 

Primitive Neuro-Ectodermal Tumors (PNET)

MRI of a Primitive Neuro-Ectodermal Tumor (PNET) in the brain

MRI of a Primitive Neuro-Ectodermal Tumor (PNET) in the brain.

Credit: NCI-CONNECT Staff

PNETs are primary central nervous system (CNS) tumors. This means they begin in the brain or spinal cord. PNET is a term that stands for a group of tumors, and these tumors are currently being reclassified and given other specific names based on their molecular features.

What are the grades of PNETs?

The group of tumors, formerly known as PNETs, are Grade IV tumors. This means they are malignant (cancerous) and fast-growing. These are tumor types that belong to this group:

  • Medulloepithelioma
  • CNS neuroblastoma
  • CNS ganglioneuroblastoma
  • Embryonal tumor with multilayered rosettes and other unspecified embryonal tumors 

Who is diagnosed with PNETs?

PNETs occur more commonly in children, but can occur in adults. PNETs are very rare tumors, and their classification is evolving

What causes PNETs?

The cause of PNETs is not known. Some PNETs are related to genetic changes.

Where do PNETs form?

PNETs are commonly found in the brain and rarely, in the brainstem or spinal cord. PNETs is a group of tumors that form from the ectoderm, the outermost layer of cells of an embryo in early development.

Primitive Neuro-Ectodermal Tumors (PNET) Statistics

Do PNETs spread?

PNETs can spread to other areas of the CNS and organs. When first diagnosed, about one-third of patients’ tumors have spread.

What are the possible symptoms of PNETs?

Symptoms related to PNETs depend on the tumor’s location. People with PNETs may have headaches, seizures, thinking or memory problems, weakness, numbness, or problems with balance and movement. People with PNETs in the spine may have bowel or bladder incontinence, and pain in the back and legs.

What are the treatment options for PNETs?

The first treatment for PNETs 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.

People with PNETs usually receive further treatments. Treatments may include radiation, chemotherapy, or clinical trials. Surgery is usually followed by radiation in patients 3 years old or older, sometimes including the brain and the spine. Clinical trials, with new chemotherapy, targeted therapy, or immunotherapy drugs, may also be available and can be a possible treatment 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.

What do PNETs look like on an MRI?

PNETs usually initially appear as a single mass in the cortex, the outer layer of the brain. PNETs often enhance with contrast and more than one tumor can be identified. Sometimes, there are cysts or fluid collections found within the mass. PNETs may also have some swelling around them.

  • Posted: September 17, 2018

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