Prevalence:

• 1 in 50 fetuses at 20 weeks’ gestation.
• More than 90% resolve by 26 weeks.

Ultrasound diagnosis:

• Single or multiple cystic areas (>2 mm in diameter) in one or both choroid plexuses of the lateral cerebral ventricles.

Associated abnormalities:

• Associated with increased risk for trisomy 18 and possibly trisomy 21.

Investigations:

• Detailed ultrasound examination for presence of other markers of trisomies 18 and 21. In the absence of other markers there is no need for invasive testing.

Follow up:

• Follow-up should be standard.

Delivery:

• Standard obstetric care and delivery.

Prognosis:

• Good.

Recurrence risk:

• Isolated: no increased risk of recurrence.
• Part of trisomies: 1%.