[Epiplexus cell (Kolmer cell) and its reaction against foreign bodies]

In 1921, Kolmer reported the free cell which is characteristically anchoring to the surface of the choroid plexus by its pseudopodal cytoplasmic processes, and later named "Kolmer cell". Phagocytic function of this cell was reported by Ariëns-Kappers in 1953, and he called this cell to "epiplexus cell". In this paper, the epiplexus cell of adult dog was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and its ultrastructure, reactions and changes against foreign bodies are described. Furthermore, obstructed ventricular catheter by choroid plexus in clinical ventricular shunt operation was observed by SEM. The structure and nature of the epiplexus cell resembles that of macrophages in other tissue. When small foreign bodies such as ink particles or red blood cells were injected into the ventricle, the reaction of the epiplexus cells was observed as an increase in their number and phagocytosis. And against the large foreign bodies, such as small strips of silicon rubber tube, a remarkable increase of the epiplexus cells were seen. These proliferated cells had many long cytoplasmic processes and laid in piles. In these above-mentioned results, we considered that the proliferative and phagocytic reaction of the epiplexus cell represents one of the causes of ventricle catheter obstruction.