Primitive neuroectodermal tumours of the central nervous system--an electron microscopic & immunohistochemical study.

A series of 75 poorly differentiated neoplasms of the central nervous system viz., medullo-blastoma, cerebral neuroblastoma, pineoblastoma and ependymoblastoma were studied by light microscopy (LM), electron microscopy (EM) and immunohistochemistry (IH). Although the predominant cells constituting these tumours appeared to be undifferentiated cells by LM and EM, many others showed evidence of differentiation into glial, neuronal or ependymal cell lines by EM and IH. It is therefore, concluded that all these neoplasms are best considered as primitive neuroectodermal tumours and these may be classified as such in neuro-oncology. They may be subclassified further on the basis of differentiation into one or more cell lines.