ABSTRACT
There are various types of congenital tumors and they may be classified in accordance with their embryonic origin (Box 76.1).
At an early stage of development there is a protrusion of the forebrain and dura through the foramen cecum into the prenasal space, which is limited by frontal and nasal bones on the anterior aspect and a cartilaginous capsule posteriorly. During further development the dural process is sealed and the foramen obliterated. Any failure of this obliterating procedure leaves a canal, a pathway favoring extension of the glial tissue, hence the development of encephaloceles or gliomas.
