Histology of Medulloepithelioma The World Health Organization has classified the<unk> s into five subtypes: neuroblastoma, ganglioneuroblastoma, medulloepithelioma, ependymoblastoma, and not otherwise specified PNET. The last one encompasses the PNETs with varying characteristics that hasn't been well defined yet. Neuroblastomas are PNETS that involve the process of cell differentiation into neurons, while ganglioneuroblastomas are PNETs that involve ganglion cells. Medulloepithelioma, on the other hand, are tumors involving the constant cell division on the epithelium tissue where bundle of neuron endings are located. Such tissue will differentiate into a similar form as the embryonic neural tube, also known as the starting structure of the central nervous system. Medulloepitheliomas also present a pattern known as rosettes, characterized by the arrangement of a bundle of cells into circular shapes and around a center or a neuropil. Ependymoblastoma also present rosettes as well as a higher density of cells. It involves the process of differentiation into ependymal cells. Rosettes in Ependymoblastoma histology Further classification types have come up but not yet approved by the World Health Organization. The term "embryonal tumor with abundant neuropil and true rosettes", or ETANTR, has been proposed as a sixth subtype of PNET. However, the still unofficial term "embryonal tumor with multilayered rosettes" (ETMR) has been more frequently used and encompasses ETANTRs, medulloepitheliomas, ependymoblastomas, and variants of PNETs with presence of rosettes and with no well defined classification. PNET vs. medulloblastoma The differentiation between<unk><unk>  tumor in the central nervous system and medulloblastoma is recent. According to the World Health Organization, both tumors have the same histology but<unk><unk>  tumors occur outside the cerebellum. Moreover, it has been documented that both have different genetic expression and mutations. Another essential difference between them is the location of their respective blood vessels within the brain. It has also been theorized that PNETs influence mainly glia cells while medulloblastomas influence mainly neural behavior, however such theory hasn't been confirmed yet. Medulloblastomas are more frequent than PNETs, representing 10% of all child deaths caused by cancer. They also present better prognosis: children affected by medulloblastoma reach the 5 year survival mark in 70-80% of cases, while children affected by PNET reach the 5 year survival mark in less than 50% of cases.
Central nervous system primitive neuroectodermal tumor
Central nervous system cyst
Extracranial germ cell tumor
Pediatric ependymoma
Primary central nervous system lymphoma
Primitive neuroectodermal tumor
Glial tumor
Central neurocytoma