<正> Medulloblastoma is a primitive embryonaltumor.It accounted for about 4% of interacran-ical tumors

but the mortality is very high.Theultrastructure and tissue origin of this tumorare still not quite clear.Recently we inves-tigated 8 medulloblastoma specimens confirmedby pathology.The results were as follows:The tumor tissue obtained from the operat-ing room was immediately cut into small pieces