Prevalence:

• 1 in 10,000 births.

Ultrasound diagnosis:

• One or multiple cystic lesions in the brain that communicate with the ventricles, subarachnoid space or both. The cysts are either in the fissures or in the midline.
• There are two types of porencephaly:
  • Type I: unilateral, due to hemorrhage or ischemia.
  • Type II: bilateral, due to neuronal migration disruption.

Associated abnormalities:

• Incidence of chromosomal defects is not increased.
• Structural defects: mainly ventriculomegaly.

Investigations:

• Detailed ultrasound examination, including neurosonography.
• TORCH test for fetal infections.
• Fetal brain MRI at ≥32 weeks’ gestation for diagnosis of grey matter heterotopias, late sulcation and migration anomalies.

Follow up:

• Ultrasound scans every 4 weeks to monitor the evolution of the lesion and that of ventriculomegaly.

Delivery:

• Standard obstetric care and delivery.

Prognosis:

• Depends on the size and location of the lesion but neurodevelopment is often normal.

Recurrence:

• No increased risk of recurrence.