The term supratentorial Primitive Neuroectodermal Tumor (PNET) no longer exists in the current WHO brain tumor classification.
These tumors are described as embyonal and classified into two major groups:
- Medulloblastoma
- Non-Medulloblastoma
- Derived from neuroepithelial stem cells (cells that are arrested in various stages of differentiation)15
Central nervous system PNETs are classified by their location relative to the tentorium20:
Infratentorial:
- Tumors arising below (infra) the tentorium
- Called medulloblastomas
Supratentorial:
- Tumors arising above (supra) the tentorium
- Called Supratentorial PNETs
Type of PNET |
Location |
Incidence of PNET |
Infratentorial (medulloblastoma) |
Cerebellum |
>90% |
Supratentorial |
Above tentorium |
<10% |
In the following diagram, S points to the supratentorial brain, T points to the tentorium and I points to the infratentorial brain or cerebellum.
