Goblet Cells in Colloid Cyst of the Third Ventricle *

It has been rather generally accepted that colloid cysts of the third ventricle are derived from persisting remnants of the paraphysis2' 5 as first suggested by Sj6vall6 in 1909. The paraphysis is a variety of extraventricular choroid plexus found best developed in adult forms of the ganoid fishes and certain amphibia, but is present in the embryos of all vertebrates, including man. This structure is formed by an evagination of the ependymal lining of the roof of the diencephalon, in the superior part of the lamina supraneuroporica. It is lined by a single layer of columnar ependymal cells which McLean5 has shown to bear cilia. The blood vessels which impart the reddish or pinkish color to it are on the outside of its acinar ramifications. Many authors have commented on the glandlike appearance of its epithelial cells, but it has never been shown experimentally that it is actually a secretory organ. Most probably, its secretion, should it have one, would resemble cerebrospinal fluid. Some authors7 are not at all convinced of the paraphysial origin of these tumors. Our finding of goblet cells, which could be stained positively with mucin-specific stains, in a typical colloid cyst of the third ventricle has, it would seem, cast further doubt upon the correctness of this view.