Primitive Neuroectodermal Tumor, also referred to as PNET, is a category of malignant (cancerous) tumors which appear similar under the microscope to medulloblastoma but occur primarily in the top part of the brain (the cerebrum). This category of tumors is molecularly and clinically diverse and includes the following diagnoses:
Pineoblastoma
- CNS neuroblastoma with FOXR2 activation
- CNS high-grade neuroepithelial tumor with BCOR alteration
- CNS Ewing sarcoma family tumor with CIC alteration
- CNS high-grade neuroepithelial tumor with MN1 alteration
- CNS embryonal tumor not otherwise specified
Individually, each of these are very rare tumors.
Location
Symptoms
Treatment
Surgery is the standard initial treatment for these tumors. Because of their large size, tendency to spread, and extensive blood supply, total removal may not be possible at the time of diagnosis, and chemotherapy may be used to shrink the tumor to make surgical removal safer.
After surgery, treatment includes radiation to the brain and spinal cord (in children ages 3 and up at diagnosis) followed by chemotherapy. Radiation therapy is generally delayed in very young children due to the risks to the developing brain. For children diagnosed with PNET as infants or toddlers, chemotherapy is used alone after surgery.
Prognosis
Prognosis means a prediction of outcome. This information is usually based on information gathered from groups of people with the same disease. It is important to remember these statistics are not individualized.
In 2021, the PNET group of tumors began to be classified differently. Due to this change, prognostic data for PNET is limited.
Incidence
Age Distribution
Risk Factors
Molecular Profile
Molecular profiling is the detection of specific genes, proteins, or other molecules in a tumor. This information helps confirm tumor diagnosis, inform treatment options, and predict prognosis.
Molecular analyses of the PNET group of tumors such as assessment for mutations or methylation analysis should be clinically performed to obtain a specific diagnosis for tumors in the PNET category in order to provide more specific prognostic information to the patient. Molecular markers commonly found in the PNET group of tumors include FOXR2 activation, BCOR alteration, CIC alteration, and MN1.
Additional Resources
Content last reviewed:
April 2022 by Holly B. Lindsay, MD, MS and Donald Williams (Will) Parsons, MD, PhD
