A meningocele is a protrusion of the meninges without any accompanying spinal cord or nervous tissue. It typically occurs along the spinal column and can range in size. It is an occult form of spinal dysraphism resulting from a neural tube defect involving failed closure of the caudal neural tube. The etiology is multifactorial, and reduced folic acid is associated with the condition. A midline fluid-filled mass covered by skin is typically visible on examination. There is no spinal cord or nerve involvement; therefore, meningoceles are not typically associated with neurologic deficits. If spinal neural tissue is contained in the defect, it is called a meningomyelocele.
Cranial or high cervical meningoceles can be associated with hydromyelia or Chiari II malformations. If the cranial herniation contains neural tissue, it is called a meningoencephalocele.
Rarely, meningoceles can occur spontaneously or be iatrogenic (eg, occur after surgery).