The tanycytic ependymoma is an extremely rare, primitive neuroectodermal tu
mor, arising from the ependymoglial cells or tanycytes. Such cells are gene
rally seen in the primitive nervous system instead of the mature ependymal
cells. The tanycytic ependymoma described in this report was found in a 42-
year-old man. Histological analysis strongly suggested that this tumor orig
inated from a primitive progenitor cell, the ependymoglia or the tanycyte i
n the lateral ventricle.