Nasal glioma.

Light and electron microscopic studies in a case of nasal glioma revealed a tumor composed nearly entirely of astrocytes. No ganglion cells or neurons were present and the mass was not surrounded by a capsule reminiscent for meningeal tissue. The vasculature resembled dermal patterns rather than typical central nervous system. No bone defect or connection to endocerebral tissue could be detected in the present case. Nasal glioma represents an ectopic focus of astrocytes, comparable to a hamartoma, rather than a true tumor or a herniation of brain tissue.