Encephalocele is a neural tube defect that occurs when the neural tube (the narrow channel that connects the brain and the spinal cord) does not close completely during pregnancy. Encephaloceles are characterized by the herniation of brain through the skull that is still connected to intracranial tissues.
An encephalocele is present at birth and appears as a sac-like protrusion of the brain and membranes through a hole in the skull. Encephaloceles typically form on the face — between the forehead and nose — or at the back of the skull.
Although rare in Europe and North America, encephaloceles are relatively common in Asia and the Middle East. The cause of these conditions remains unknown but is not thought to be genetic in most cases. Associated anomalies include microcephaly, hydrocephalus, macrophthalmia, agenesis of the corpus callosum, cortical atrophy and ventricular dilatation.
These masses may appear anywhere in the skull and are most common on the back of the head. Those originating in the face account for 15 percent of cases and are classified by their location (e.g., nasal frontal, nasal orbital, frontal nasopharyngeal, etc.).
Management of these masses includes removal or reduction of the herniated tissue, reduction of the herniated membranes and repair of any bony defects or bony displacements.
Surgery is performed early in life to prevent progression of the process and prevent damage to the herniated tissue. Encephaloceles present in the face are most often treated with a combined procedure requiring the expertise of plastic surgery and neurosurgery.
In this operation, an ear-to-ear, or coronal incision is used and the encephalocele and its sac are removed. Your child’s surgeon may need to remove the frontal bone and adjacent bones through which the encephalocele protrudes. Following excision of the encephalocele, any displaced bones are returned to their more anatomically correct position and any defects are bone grafted. The external soft tissue is tailored and tucked for optimal aesthetic results.
If the encephalocele is located at the base of the skull, typically in the sinuses or clival region, it may be removed completely through the nose. This minimally invasive procedure (nasal endoscopic neurosurgery) is done with a tool called an endoscope (a small camera that passes in through the nose), without any incision on the face or skin. Since this procedure accesses the tumor through the nose (or sometimes the mouth depending on the exact location), your child’s neurosurgeon will typically work with an ENT specialist.
Prognosis is dependent upon the amount of tissue in the sac that needs to be removed and the character of the residual brain tissue which remains.
CHOP has a long history of providing multidisciplinary care for children with encephaloceles. Treatment of this complex neural tube defect requires the expertise of both neurosurgeons and plastic surgeons to optimize neural function and facial appearance and form. It is important that your child be treated in a center that has experience in the management of these lesions, especially since the condition is so rarely seen in North America.
CHOP’s Craniofacial Program provides coordinated, multidisciplinary care to children with encephaloceles, bringing together the many pediatric specialists needed to provide the best outcomes for your child in one institution.
Reviewed by: Scott P. Bartlett, MD and Jesse Taylor, MD
Date: April 2014