Meningoencephalocele is a type of encephalocele, which is an abnormal sac of fluid, brain tissue, and meninges (membranes that cover the brain and spinal cord) that extends through a defect in the skull. There are two main types of Meningoencephalocele, which are named according to the location of the sac. The frontoethmoidal type is located at the frontal and ethmoid bones while the occipital type is located at the occipital bone. Hydrocephalus, abnormalities of the eyeball and tear duct, and other findings have been associated with the condition. Some affected individuals have intellectual or physical disabilities while others have normal development and abilities. The condition is typically congenital (present at birth) but has been reported to develop by chance in older individuals in rare cases. The underlying cause of the condition is uncertain, but environmental factors are thought to play a role.