Cephalocele

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 recognized geographical variation between types; however, this has been speculated to be underestimated as many may result in elective termination, in utero demise, or stillbirth. There may be a female predilection 11.

The presentation may vary widely depending upon the type of defect.

Examples include:

  • large mass seen extending from cranium on prenatal ultrasound
  • small cranial soft tissue mass palpated in childhood (e.g. atretic cephalocele)
  • in utero demise (severe defect)

It is thought to arise due to failed closure of the rostral end of the neuropore. This may result from either overgrowth of neural tissue in the line of closure, or a failure of induction by adjacent mesodermal tissues which interferes with normal skull closure.

Cephaloceles can be classified into 5 types, based upon the herniated contents 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 implies a poor prognosis.

Malformations of the central nervous system
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Article information

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

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Cases and figures

  • Case 1: atretic cephalocele
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