A cephalocele is a rare birth defect that is characterized by a sac-like mass protruding through a defective opening in the skull. The sac varies in size that typically consists of herniated meninges and brain tissue (meningoencephalocele or encephalocele) or fragments of disorganized neural tissue. Alternatively, the sac may contain only the meninges (cranial meningocele) or it may include part of the ventricle filled with CSF (encephalocystocele) covered by skin (from PMID:24931720).