Most fetuses with Congenital Cystic Adenomatoid Malformation do not require intervention during the pregnancy and will do well with management after birth (usually surgery to remove the abnormal piece of lung).
Fetuses with large CCAM on prenatal ultrasound are followed closely by our center, usually once per week, but sometimes 2-3 times/week. Fetuses that get sick exhibit hydrops fetalis on ultrasound. Fluid around the heart, lungs, intestine as well as thickening of the skin or placenta, and polyhydramnios are signs of hydrops fetalis. When hydrops fetalis develops in fetuses with CCAM, nearly 100% of fetuses will die without treatment. In fetuses with CCAM's without hydrops, nearly 100% survive.
At our fetal treatment center, we pioneered fetal surgical techniques for treatment of fetuses with CCAM and hydrops. Those fetuses that have macrocystic (large sacs) CCAM can have a procedure known as a thoracoamniotic shunt. This procedures drains fluid out of the large sacs, decreasing the size of the CCAM. The thoracoamniotic shunt procedure is performed through a needle, and the mother does not need an incision for this minimally invasive procedure.
A few fetuses with very large lesions that will make resuscitation after delivery dangerous will need special management at birth: a specialized delivery called the EXIT (ex utero intrapartum treatment) procedure. We developed the EXIT procedure for management of fetal airway emergencies, but it can be adapted to allow surgical resection of the CCAM while the baby remains attached to the placenta. The EXIT procedure can also be used to facilitate immediate support using extracorporeal membrane oxygenation (ECMO).
The most effective treatment of very large CCAMs causing hydrops is fetal surgical resection of the CCAM. Only the most severely affected fetuses are candidates for this intervention. In those with a microcystic CCAM (without a large sac), open fetal surgery has been the only option for a chance at survival. Fetal surgery is only offered when there is evidence of hydrops (heart failure) in the fetus. Women with signs of pre-eclampsia (high blood pressure, protein in the urine) have mirror syndrome and are not candidates for fetal intervention.
Fetal surgical resection to remove the abnormal lobe of the lung (lobectomy) is the same surgery that is done after birth. Open fetal surgery is similar to a c-section without clamping the umbilical cord. The fetus is returned into the womb after surgery to continue the pregnancy.
While this procedure gives hope for survival (about 50% of babies survive) mothers must undergo a significant procedure, and the risk for preterm labor after fetal surgery is high. Many of these babies, because of the preterm labor of the mother are born as premature infants and have the risks associated with prematurity.
A new treatment for fetuses with microcystic CCAMs that have hydrops has emerged here at UCSF. Our group has discovered that steroids, which are commonly given in pregnancy, may help fetuses with large CCAMs to either prevent or reverse hydrops fetalis. Our study published in 2003 showed the potential efficacy of steroids for treatment in these situations. Groups subsequently at the Children's Hospital of Philadelphia and the University of Cincinnati have found similar promising results.
Together, our three groups are embarking on a trial to determine whether steroids might be effective in preventing fetuses with large microcystic CCAM's from developing hydrops fetalis. This important study will help answer the question of whether administration of steroids to the mother, a benign treatment, is helpful to fetuses with large CCAM's whose previous prognosis was poor, and for whom the only previous treatment option was open maternal-fetal surgery.
You may be eligible to be considered for this clinical trial. For more information please visit Investigation of Prenatal Steroids for Treatment of Prenatally Diagnosed CCAMs.
Fetuses with small or moderate-sized Congenital Cystic Adenomatoid Malformations that do not change much during pregnancy can be successfully managed after a normal birth. They usually do not have any difficulty during pregnancy or any trouble breathing at the time of birth. If imaging studies (X-ray or CT scan) show a significant CCAM mass, or if the baby has any difficulty breathing, the CCAM should be surgically removed to prevent the development of infection or possible cancer later in life. This surgery is quite safe even in the first year of life and does not compromise lung function or the normal development of the baby. These children will have perfectly normal lung function.
If the mass is very small and the baby has no difficulty breathing, the baby can go home. If the mass remains very small on CT scan at 3-6 months, surgery is not necessary. However, if the CCAM is larger or the baby develops any symptoms, then the CCAM should be removed.