Some applications of scanning electron microscopy for the study of biopsies in central nervous system pathology

The present report describes SEM observations on a variety of subjects, such as the walls of cerebral ventricles under pathological circumstances (hydrocephalus) as well as the surface morphology of abnormal cavities like arachnoid cysts and subdural hematomas. In the human specimens with hydrocephalus the changes consisted of degeneration of ependymal cilia, progressing to denudation of the ependyma while rupture of the ependymal layer was also seen. In experimental animals where the hydrocephalus was induced by agents (presumably irritant to the tissue), the presence of reactive supraependymal cells was observed next to the manifestations of ependymal degeneration. With the SEM the wall of arachnoid cysts showed numerous microvilli of stubby appearance with interspersed projections of diverse shape in the individual cases. SEM may aid in the diagnosis of arachnoid cysts, particularly in differentiating them from traumatic leptomeningeal cysts.