What Are Fetal Neck Masses (FNM)?

FNM are rare conditions that include cervical teratomas and lymphangiomas. These masses can grow so large that they can block the fetal airway and esophagus. A blocked esophagus impairs the ability of the fetus to swallow resulting in increased amniotic fluid (polyhydramnios). This condition increases the risk for preterm labor and premature delivery. If the mass blocks the airway, the baby may not be able to breathe normally after delivery. This results in decreased oxygen and potential brain injury. If these pregnancies are not properly managed, babies can die from the inability to breathe at the time of delivery.

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Cervical teratomas are tumors of the neck that arise from many different cell types of the body. This condition is extremely rare and those requiring fetal intervention are even less common. The cause of cervical teratomas is unknown and has not been associated with any other maternal or fetal conditions. Lymphangiomas are also rare and develop from abnormal growth of lymphatic tissue. If they occur in the neck, cervical teratomas and lymphangiomas can present as a FNM that obstructs the esophagus and airway. A fetal MRI may be recommended to evaluate these structures.

Although these are two very different conditions, they can cause the same problems during pregnancy and at the time of delivery. As a result, they are managed and treated similarly during pregnancy.

How are Fetal Neck Masses (FNM) Treated?

Neck masses typically do not require fetal intervention. If the mass is small and does not appear to be obstructing the esophagus or airway, your pregnancy may continue with careful monitoring. However, special considerations and planning are made at time of delivery if the mass becomes extremely large and results in an increase in amniotic fluid volume (hydramnios). This condition may increase your risk for preterm labor and premature delivery. Your doctors at the Center will continue to monitor your pregnancy for these changes.

What Special Considerations Should Be Made for Delivery?

Type of delivery: If the neck mass remains small and your doctors are not concerned about an obstructed airway, then cesarean delivery is not necessary. However, if the neck mass grows large enough it may obstruct the labor process or cause concern for airway obstruction. Your doctors at the Center may suggest an EXIT procedure (Ex Utero Intrapartum Treatment) which requires a Cesarean delivery.

Place of delivery: Babies with a large FNM require a hospital with adult and pediatric specialists to care for mother and child. Because of the concerns with breathing at birth and the potential need for an EXIT procedure, this disease requires specialists that can care for the mother and child at delivery as well as after birth. If the FNM requires surgical removal, the infant must be in a facility that has neonatal surgical and intensive care capabilities. Therefore, delivery should be in a facility with a neonatal intensive care unit and immediate access to a pediatric surgeon.

Time of delivery: There is no reason to intentionally induce early delivery. As long as the fetus and mother are stable, the pregnancy should be allowed to proceed to term. If the baby's condition deteriorates, earlier delivery may be necessary.

What Will Happen at Birth?

If the FNM becomes extremely large, your doctors at the Center may have concerns about breathing difficulties for your baby at birth. If the mass appears to grow, an EXIT procedure may be considered at the time of delivery.

An EXIT procedure allows your doctors to examine the airway and provide a breathing tube (intubation) while the baby is still connected to the placenta by the umbilical cord and supported by the mother. This allows doctors to perform several procedures to ensure your baby's safety. The EXIT procedure is performed through a Cesarean incision. Immediately following delivery, doctors will carefully evaluate mother and child and begin treatment if necessary. If all goes well, most infants will be born without immediate problems. For more details, please visit the section on EXIT procedures

What Are the Long-Term Outcomes and Considerations?

Depending on the diagnosis, most infants will need an operation to remove the mass. Further treatment after removal of cervical teratomas depends on the characteristics of the tumor. Similarly, lymphangiomas will be carefully evaluated and depending on its characteristics, surgery may be an option. Your pediatric surgeon will educate you on your specific FNM and appropriate treatments.

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When you contact The Fetal Center, you will be in touch with a dedicated coordinator who will walk you through the process step-by-step and help you to understand every aspect of your care.

The Fetal Center at Children's Memorial Hermann Hospital
UT Professional Building
6410 Fannin, Suite 210
Houston, Texas 77030

Phone: (832) 325-7288
Toll free: (888) 818-4818
Fax: (713) 383-1464
Email: thefetalcenter@memorialhermann.org

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Located within the Texas Medical Center, The Fetal Center is affiliated with McGovern Medical School at UTHealth Houston, UT Physicians and Children’s Memorial Hermann Hospital.