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PNET belongs to the [[Ewing family of tumors]].
==Classification==
It is classified into two types, based on ___location in the body: peripheral PNET and CNS PNET.
===Peripheral PNET===
[[File:Peripheral PNET CD99 200x.jpg|thumb|CD99 staining of tissue from peripheral PNET]]
The peripheral PNET (pPNET) is now thought to be virtually identical to [[Ewing's sarcoma|Ewing sarcoma]]:
"Current evidence indicates that both Ewing's sarcoma and PNET have a similar neural phenotype and, because they share an identical chromosome translocation, they should be viewed as the same tumor, differing only in their degree of neural differentiation. Tumors that demonstrate neural differentiation by light microscopy, immunohistochemistry, or electron microscopy have been traditionally labeled PNETs, and those that are undifferentiated by these analyses have been diagnosed as Ewing's sarcoma."<ref name="robbins">Kumar, Vinay; Fausto, Nelso; Abbas, Abul (2004) ''Robbins & Cotran Pathologic Basis of Disease'' (7th ed.). Saunders. Page 1301. {{ISBN|0-7216-0187-1}}.</ref>
===PNET of the CNS===
{{main|Central nervous system primitive neuroectodermal tumor}}
[[File:PNET.jpg|thumb|Supratentorial central PNET in a 5-year-old patient]]
PNET of the CNS generally refer to supratentorial PNETs.
* In the past [[medulloblastoma]]s were considered PNETs; however, they are genetically, transcriptionally and clinically distinct. As such, "infratentorial" PNETs are now referred to as medulloblastoma {{Citation needed|date=March 2013}}.
* [[Pineoblastoma]]s are embryonal tumours originating in the [[pineal gland]] and are likely distinct from supratentorial PNETs.
==Genetics==
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