exencephaly

Exencephaly is a lethal congenital fetal brain developmental anomaly (neural tube defect) considered to be a precursor to anencephaly in the acrania-exencephaly-anencephaly sequence.

Pathology

It is characterized by calvarial absence and loss of fetal brain tissue to variable degrees and is considered a precursor to anencephaly  in the acrania-exencephaly-anencephaly sequence.

Markers

• maternal serum alpha fetoprotein (MSAFP) levels are highly elevated (x 2.5 MoM)

Radiographic features

Imaging features have some overlap with that of anencephaly except that there is some brain tissue presence:

• cranial vault is absent or poorly formed, cephalad to orbits
• the nasal bone may be absent in most cases
• brain tissue is herniating or dangling in amniotic fluid
• brain tissue may be attached to the amniotic membrane

Treatment and prognosis

Exencephaly is a precursor to anencephaly, and essentially a fatal condition. Depending on local laws, advise and counseling for abortion are to be given to the parents.

See also

• acrania: calvarial absence but almost all brain tissue present
• anencephaly: absence of calvarium as well as brain tissue

Siehe auch:

• Osteogenesis imperfecta
• Amniotisches-Band-Syndrom
• Meningoenzephalozele
• Neuralrohrdefekt
• Hypophosphatasie
• Anenzephalie
• Achondrogenesie
• Mikrohydranenzephalie

und weiter:

• obstetric curriculum
• cyllosoma
• rachischisis
• acrania-exencephaly sequence
• Hydranenzephalie