Chorioangioma

A chorioangioma is a benign (noncancerous) tumor of the placenta. Chorioangiomas are made up of blood vessels from the chorionic tissue, which is the tissue on the fetus’s side of the placenta.

Chorioangiomas are relatively rare, occurring in about 1 percent of pregnancies. Larger chorioangiomas (bigger than 4 cm) are even less frequent, appearing in approximately 1 in every 3,500 to 9,000 pregnancies.

Most chorioangiomas don’t cause symptoms or adverse effects on the fetus or the pregnant person. Rarely, these pregnancies can be complicated by high fetal cardiac output failure that leads to excessive accumulation of amniotic fluid (polyhydramnios). In these cases, the pregnant person may feel abdominal tension caused by the overextended uterus, difficulties breathing, or even premature contractions. Complications in fetal development might not cause symptoms and can only be detected by imaging.

The exact cause of chorioangiomas hasn’t been identified. However, it’s understood that they typically develop during the early stages of pregnancy, specifically during the development of the placenta.

Chorioangiomas are typically diagnosed through prenatal ultrasounds in the second trimester. Larger chorioangiomas may be seen as solid masses, often near where the umbilical cord enters the placenta. In pregnancies complicated by chorioangioma, fetal echocardiograms are important diagnostic tests that check fetal heart function. When chorioangiomas are smaller or asymptomatic, they may go undetected in prenatal ultrasounds and are only discovered when the placenta is examined after delivery.

In most cases, small chorioangiomas that don’t cause symptoms won’t require treatment and can be managed through close prenatal monitoring. However, larger chorioangiomas or those that cause complications might require intervention. At Boston Children’s Hospital, we consider a number of factors when treating chorioangiomas, including their size, their location on the placenta, and their effect on the well-being of the fetus and pregnant person. Treatment options may include:

• Delivery: If the chorioangioma poses a significant risk to the fetus in relatively advanced gestational ages, early delivery may be considered to minimize potential complications.
• Fetal interventions: In certain cases, specialized fetal therapies may help address complications associated with chorioangioma. Fetal treatments include:
  • Laser coagulation: Direct delivery of laser energy into chorionic vessels through a fiber optic cable inserted into the tumor using a special camera called a fetoscope.
  • Radiofrequency ablation: Thermal energy generated by radiofrequency waves to heat and shrink the tumor tissue.
  • Embolization: Injection of substances like microspheres into the blood vessels that feed the chorioangioma. These particles block blood flow to the tumor, causing it to clot and shrink.
• Postnatal management: After birth, the newborn will be evaluated. Managing chorioangiomas may involve monitoring for complications related to the condition and providing appropriate care as needed.

At Boston Children’s, the Fetal Care and Surgery Center takes a multidisciplinary approach to treating placental chorioangiomas and other fetal conditions. Our team includes maternal-fetal medicine specialists, neonatologists, fetal surgeons, radiologists, cardiologists, and others who work with your own prenatal care and obstetrics team to assess, manage, and treat these conditions, ensuring the best possible outcome.