- 1 in 25,000 births.
- Supratentorial mid-line translucent elongated cyst with active arteriovenous flow within the cyst demonstrated by color Doppler.
- The defect develops in the early first trimester, but the aneurysm becomes sonographically apparent just in the third trimester.
- In 90% of cases there is high-output heart failure with secondary hydrops.
- The incidence of chromosomal abnormalities or genetic syndromes is not increased.
- Neurosonography to exclude secondary brain lesions (ischemia and leukomalacia).
- Echocardiography for detection of early signs of heart failure.
- Follow-up scans should be arranged every 1 week, mainly to determine the time of delivery depending on the risk of developing heart failure.
- Place: hospital with neonatal intensive care and pediatric surgery.
- Time: 38 weeks.
- Method: cesarean section.
- One third have a good outcome after postnatal intervention by embolization. One third die during the procedure and one third survive but with neurodevelopmenal delay.
- If there is hydrops fetalis at the time of diagnosis then the prognosis is poor.
- No increased risk of recurrence.