- A congenital neural tube closure defect resulting in the protrusion of the brain through a skull opening. When the protrusion includes the meninges, the term encephalomeningocele is used.
- Brain tissue herniation through a congenital or acquired defect in the skull. The majority of congenital encephaloceles occur in the occipital or frontal regions. Clinical features include a protuberant mass that may be pulsatile. The quantity and location of protruding neural tissue determines the type and degree of neurologic deficit. Visual defects, psychomotor developmental delay, and persistent motor deficits frequently occur.