Prevalence:

• 1 in 5,000 pregnancies.

Ultrasound diagnosis:

• Hypo- or hyperechoic, well-circumscribed mass, which is usually located underneath the chorionic plate near the umbilical cord insertion, and often protrudes into the amniotic cavity.
• Color Doppler demonstrates large vascular channels around and within the tumor.

Associated abnormalities:

• Large tumours may result in fetal anemia and thrombocytopenia (due to sequestration of red blood cells and platelets by the tumor), fetal heart failure, hydrops and placentomegaly (due to a hyperdynamic circulation as a result of arteriovenous shunting), polyhydramnios (due to direct transudation into the amniotic fluid and due to fetal polyuria, secondary to the hyperdynamic circulation) and maternal mirror syndrome (generalized fluid overload and preeclampsia).

Investigations:

• Detailed ultrasound examination, including echocardiography for assessment of cardiac function and measurement of fetal middle cerebral artery peak systolic velocity (MCA PSV) for diagnosis of fetal anemia.

Follow up:

• Follow-up scans every 2 to 3 weeks to monitor growth of the tumor, heart function, MCA PSV and amniotic fluid volume.

• Ultrasound guided laser coagulation of vessels within the tumor, fetal blood transfusions and amniodrainage may become necessary.

Delivery:

• Place: hospital with neonatal intensive care.
• Time: 38 weeks. Earlier if there is evidence of poor growth, fetal hypoxia or hydrops.
• Method: induction of labor aiming for vaginal delivery, unless the fetus is hydropic and hypoxic.

Prognosis:

• Symptomatic chorioangiomas carry a high risk of perinatal death. The neonate may have severe microangiopathic hemolytic anemia and thrombocytopenia.

Recurrence risk:

• No increased risk of recurrence.