Cephalocele refers to the outward herniation of CNS contents through a defect in the cranium. The vast majority are midline.

The estimated incidence is 0.8-4:10,000 live births 13 with a well recognised geographical variation between sub-types. These may be a greater female predilection 11.

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It is thought to arise due to failure of closure of the rostral end of the neuropore resulting from either overgrowth of neural tissue in the line of closure or a failure of induction by adjacent mesodermal tissues which in turn interfere with normal closure of the skull.

There are two main subtypes:

Cephalocoeles can also be subclassified into 5 subtypes 15:

Additional congenital anomalies may be present in up to 50 % of cases. They include

  • maternal serum alpha-fetoprotein (MSAFP) may be elevated

Sonographically, these lesions may appear as:

  • a cyst protruding from the fetal calvarium representing a meningocele or cyst within cyst appearance
  • a solid mass protruding from the calvarium representing a herniated brain: encephalocele 
  • either or both of the above associated with a defect in the calvarium

The overall prognosis is variable dependent on severity and other associations (presence of hydrocephalus, microcephaly, etc). If a large cephalocele is noted in an antenatal ultrasound scan it generally implicates a poor prognosis.

Malformations of the central nervous system
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Article information

rID: 9710
Synonyms or Alternate Spellings:
  • Cephaloceles
  • Cephalocoeles
  • Cephalocoele

Cases and figures

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    Case 1: atretic cephalocele
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