Encephalocele, also referred to as meningoencephalocele, is a cranial defect that causes brain tissue and the membranes that cover the brain to protrude through an opening in the skull. This diagnosis includes both encephaloceles, which are sacs that contain brain tissue and the membranes that cover the brain, and meningoceles, which are sacs that contain the membranes and cerebrospinal fluid but no brain tissue.
Encephaloceles can occur at the back and base of the skull (occipital) or in the front, center of the skull where the forehead is. An occipital encephalocele is considered part of the spectrum of neutral tube defects. 7-15% of cases of neutral tube defects present with an encephalocele.
The vast majority of encephaloceles have an associated congenital anomaly, chromosomal abnormality, or structural malformation. Encephaloceles are associated with agenesis of the corpus callosum, amniotic band syndrome, anencephaly, body-stalk anomaly, Chiari malformation, cleft lip and palate, hydrocephalus, oligohydramnios, polyhydramnios, trisomy 13, and trisomy 18.
The prognosis for encephaloceles depends on the location and the presence of additional anomalies. Encephaloceles are associated with a higher rate of intrauterine death.
The recurrence risk for encephalocele is based on the presence of additional anomalies; the recurrence risk for an isolated encephalocele is non-existent.