THE RELATIONSHIP between cell rests and gliomas in certain parts of the central nervous system has been pointed out by various authors.1 The region of the fourth ventricle, particularly its roof, has been cited as being rich in cell rests,2 accounting for the various gliomas arising there. Cushing, in his reports on medulloblastomas in 19301l and on cerebellar astrocytomas in 1931,1m emphasized his belief that these tumors arose from embryonal cell rests in the roof of the fourth ventricle. The Kernohans,1i in 1935, supported a similar view for ependymomas arising in this region. Globus and Kuhlenbeck,1o in 1942, showed that the subependymal cell plate in the region of the fourth ventricle, as well as in other parts of the brain, could be the seat of embryonal cell rests giving rise to subependymal plate gliomas.
Although many observations have been reported on the occurrence of