What Is PNET?

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Primitive Neuroectodermal Tumors (PNETS) of the central nervous system (CNS-PNETs) are identified as highly aggressive large tumors that are found in the brain and spine. Hence, when we talk about PNETs in this web-site we are referring to the CNS-PNETs.



CNS PNETs can be distinguished from PNETs occurring outside the central nervous syste (referred to as peripheral PNETs). This web-site is dedicate to CNS PNETs.

CNS PNET’s are now referred to as Embryonal Tumours (discussed below).




PNETs are extremely aggressive.





PNETs tend to strike in children and young adults.

There have been some cases where PNET has been found in persons of middle age. This is extremely rare.





It is very difficult to predict the survival course for PNET. The survival rate depends on the age of the child, whether radiation is an option, the size and location of the tumour and the type of PNET. This is discussed in more detail below

Change of name to ‘Embryonal tumours’

The classification of brain tumours is governed by the guidelines published by the World Health Organisation (WHO). CNS-PNETs are now being described as Embryonal Tumours under the 2016
World Health Organisation’s system of classification of brain tumours. Eventually, the name PNET will be phased out and a new name will
be introduced for each type of PNET, however, for now the name PNET is still used in a general sense to describe these tumours as a group.

General facts about PNET


  • CNS PNETs are a group of tumors that are rare and extremely diverse in character.
  • The tumours are highly aggressive and grow from undeveloped brain cells.
  • Tumors tend to attach to the part of the brain that controls movement, thought and sensation.
  • Traditionally these tumours have not been able to be well defined under the microscope however advances in technology and diagnostic techniques are now enabling doctors to more precisely define the particular genomic pattern of a PNET tumour.

4 sub-types have been identified

Research to date has shown that 4 sub-types of PNET’s exist. Our research page discusses this in more detail.

 Who is affected

  • The cancer usually presents in young children and teenagers.
  • The majority of patients are younger children.

Survival rates

  • It is difficult to pin point the survival rate for PNETs given that the tumours are so diverse.
  • Further research is required to identify treatment outcomes and survival rates for each of the PNET subtypes.
  • All that can be said at this stage is that some PNET’s have a much higher survival rate than others.
  • Prior to the identification of the 4 sub-types, the best survival rate was regarded as 60% for those who undertake radiation.
  • Radiation tends to be avoided in very young children. This reduces their survival rate to approximately 20%-30%. However, it very much depends on the type of PNET. As depicted in our PNET Stories, we have many long term survivors who were diagnosed with PNET at a very young age.


Symptoms vary according to the location of the tumor and generally include:

  • Headaches
  • Vomiting
  • Fatigue
  • Lethargy
  • Nausea
  • Seizures
  • Behavioural or personality changes
  • Unexplained weight loss or weight gain
  • Weakness on one side of the body, or in an arm or leg
  • Pins and needles in hands or feet