Congenital Cystic Adenomatoid Malformation
What is congenital cystic adenomatoid malformation?
CCAM is a rare congenital (present at birth) birth defect that includes a cystic mass (a non-cancerous tumor that may be filled with fluid or other material) of abnormal lung tissue. This cystic mass cannot function as normal lung tissue. It is usually found in only one of the lungs (less than 2 percent are seen in both lungs) and in 80 to 95 percent of cases, is only present in one lobe of that lung. The right lung has three lobes and the left lung has two lobes. CCAM can affect any of these lobes. It is found at a slightly higher rate in males versus females. We do not know the cause of CCAM. There is no reported incidence of this type of disorder recurring in a subsequent pregnancy. We know that it is not related to anything the mother did or did not do during pregnancy.
|Type 1 lesion, which occurs in 50 percent of CCAM cases.|
Type I lesions account for 50 percent of the postnatal (after birth) cases. These are usually quite large, cystic lesions that are few in number (1 to 4). This type has a very favorable outcome.
Type II lesions account for 40 percent of the postnatal cases. This type consists of more numerous smaller cysts. This type is more commonly associated with other congenital anomalies, including those of the genitourinary, cardiac, skeletal systems as well as hydrocephalus and diaphragmatic hernia. The prognosis for type II is dependent on the severity of the associated anomalies.
Type III lesions account for only 10 percent of the postnatal cases. These are usually large, microcystic lesions that cause shifting of the organs normally found in the chest. This means that the windpipe, heart and unaffected lung are shifted and compressed. For this reason, heart function may be less than normal. This can lead to the development of hydrops (abnormal accumulation of fluid in at least two fetal cavities such as in the abdomen, around the heart, or lungs or under the skin). The prognosis for Type III is poor, especially when hydrops is seen.
Prenatal Diagnosis of CCAM:
With the use of prenatal ultrasound, CCAM is being detected earlier in pregnancy. This diagnosis must be confirmed because there are other congenital anomalies (or birth defects) that may appear similar on ultrasound. It will appear as a bright mass in the area of the chest where only lung tissue should be seen. The heart may be shifted out of position, depending on the size and location of this cystic mass.
Your obstetrician will most likely refer you to a specialist that handles high-risk pregnancies. These doctors are called perinatologists. The perinatologist will perform a targeted ultrasound and potentially other diagnostic tests to confirm the diagnosis. Fetal magnetic resonance imaging may be performed to confirm the diagnosis and document the size and location of the CCAM.
The perinatologist will follow the growth of the mass by performing serial ultrasounds. That means targeted ultrasounds will be done at regular intervals determined by the perinatologist. CCAM lesions may shrink in size; grow in size, or remain the same size. If the CCAM does grow, which will occur in a small number of cases, it can cause increasing problems for you and/or the baby, including the development of hydrops. Hydrops is abnormal fluid accumulation in various parts of the baby's body such as in the abdomen, skin, scalp or around the heart and/or lungs. Most lesions will either stay the same size or actually decrease or even disappear as the pregnancy progresses.
|Type II lesions include more numerous and smaller cysts, but they often are accompanied by other birth defects. Type II lesions occur in about 40 percent of CCAM cases.|
You will also meet with a variety of other specialists who will be caring for your baby after he/she is born. These specialists may include a neonatologist, a pediatric surgeon and a pediatric cardiothoracic surgeon if a cardiac defect is confirmed or suspected.
How does congenital cystic adenomatoid malformation (CCAM) affect my baby?
Many babies with CCAM will appear "normal" at birth without any apparent complications. If it is not diagnosed prenatally, these babies would typically go home and either never be diagnosed or would be diagnosed later when a chest X-ray or after recurrent respiratory infections. At birth, some babies born with CCAM will not be able to breath effectively due to the large mass in their chest. If the baby is unable to breath effectively on their own, this may have an effect on their heart rate. These babies need immediate intensive care to stabilize them until surgery is performed. Approximately 10 percent of the prenatally diagnosed masses will get smaller or even disappear on their own.
Because of the possible need for immediate interventions in the delivery room, it is best if these babies are born at a hospital that can care for baby and mother alike.This keeps the two of you together and avoids the trauma of having to transport the baby after birth.
There are a few institutions that offer experimental interventions prenatally for these babies. The indication for such an intervention depends on the size of the lesion, whether it appears solid or cystic, and the development of hydrops. If this is an option for your baby, it will be discussed with you.
How does congenital cystic adenomatoid malformation (CCAM) affect the pregnancy?
If CCAM is suspected, your obstetrician will likely refer you to a specialist who handles high-risk pregnancies for a targeted ultrasound. These specialists are called perinatologists. The ultrasound will assist with confirming the diagnosis.Ultrasound is also used to look at the general anatomy of the fetus for associated anomalies as well as to provide an idea of fetal well-being. Another diagnostic tool that has proven very useful in differential diagnosis for chest masses is magnetic resonance imaging, or MRI. Fetal MRI is helpful in distinguishing a cystic type tumor versus a solid tumor. Some affected fetuses will begin to accumulate fluid in various body cavities such as in the lungs, abdomen, around the heart and under the skin. This is called hydrops. If this develops, it is an ominous sign. These babies do not usually survive. Many die before birth and of those who survive to be born, the majority will die shortly thereafter.
The diagnosis of CCAM may have implications for the health of the mother. If hydrops develops, this diagnosis places the mother at a slightly increased risk for "mirror syndrome." Mirror syndrome is a preeclamptic state in which the mother "mirrors" what is happening with the baby. This syndrome can become life-threatening. The only treatment for mirror syndrome is immediate delivery.
Type III lesions are large tumors that cause other organs in the chest to shift. Type III lesions account for 10 percent of CCAM cases.
The treatment of choice for CCAM is a lobectomy. This means that the lobe in the lung that contains the cyst(s) is completely removed. The timing of surgery depends on whether your infant has breathing problems or not. If there are no breathing problems, the baby will go home from the newborn nursery. The baby will need to return for surgery after they have been given time to grow. Surgery will be performed at approximately 2 to 6 months of age. A chest X-ray and chest CT scan will be done as an outpatient procedure prior to surgery.
If the mass is so large that it interferes with the baby's ability to breath on his or her own, the surgery will be done within the first week of life. The baby will be stabilized, given time to adjust to life outside the uterus and an assessment of the mass is performed before surgery. Also, a general evaluation of the baby is performed to assess for any associated anomalies. Some of the more severely affected infants may develop persistent pulmonary hypertension. PPHN is a serious condition in which pressure in the lungs is high, forcing blood flow away from the lungs. This results in decreased amounts of oxygen in the blood going to the body. High pressure in the lungs is normal for a fetus before birth because they are not using their lungs in this function. However, after birth this high pressure needs to decrease so that an adequate blood flow can pass through the lungs to rid itself of carbon dioxide and pick up oxygen. Treatment for this condition may include inhaled nitric oxide or ECMO.
At birth, if the size of the CCAM requires immediate assistance, a tube will be passed into the baby's trachea to assist with breathing. If at all possible, the parents will be allowed to see and hold the baby in the delivery room. As soon as deemed necessary, the baby will be transferred to the Neonatal Intensive Care Unit for further stabilizing procedures. If the baby goes to the NICU and requires immediate care for breathing issues, some special lines also may be placed. The umbilical cord of a newborn typically contains two arteries and one vein. A flexible tube for giving intravenous solutions called an umbilical venous catheter will be placed in the vein in the umbilical cord so nourishment (vitamins, minerals, calories, fat) and medications can be given for a prolonged period of time. Another flexible tube will be placed in one of the arteries of the umbilical cord. This is called an umbilical artery catheter. Intravenous fluid will be given, blood can be removed and the blood pressure monitored through this line.
Medications given before surgery could include: narcotics to keep your baby free from pain, paralytics to keep your baby from moving and blood pressure medication to maintain an adequate blood pressure.
What about after surgery?
The post-operative course varies depending on when the surgery is done, the size of the CCAM, and how much lung was removed. If the CCAM involved both lungs or more than one lobe, they will have a more limited breathing ability. Also, babies with hydrops normally have a much rockier course with a poorer prognosis. Some babies with hydrops will not survive to have surgery.
After surgery your baby will need continued assistance to breath effectively. A special tube (endotracheal tube) will be passed through the vocal cords and into the windpipe.This tube is used to help with the baby's breathing. He or she will need frequent blood draws for lab work to monitor oxygenation, electrolytes, blood count and other things. After surgery, your baby may need a variety of medications including: antibiotics to fight infection; pain medication to control post operative pain; blood pressure medication to stabilize and maintain an adequate blood pressure; sedation to keep baby quiet so they do not become agitated; and paralytics to keep the baby from moving. Your baby will have IV lines placed. The type of lines used will depend on the age at which the surgery is performed. If surgery is done soon after birth, the umbilical cord artery and vein will be used. Other IV lines can be placed in your baby's hands, arms, scalp, feet or lower legs. These are started just like they were for you while in labor.
Your baby may also have a chest tube on the side of the chest from which the CCAM was removed. This helps the lung on that side re-expand into the chest space where the mass used to be. It will also drain any fluids that accumulate in the chest.
Your baby may have a urinary catheter passed into his or her bladder. This helps us keep an accurate assessment of how much urine the kidneys are making and allows us to test the urine to ensure the baby's well-being.
Your baby will not be able to eat until his or her condition has stabilized but will continue to get nourishment through the IV fluids. Because these babies cannot eat for a period of time, special nourishment is given IV typically through a central line or UVC. Total parenteral nutrition (TPN) is an IV solution that contains protein, fats, sugar, vitamins and minerals. This will supply your baby with all his or her nutritional requirements until he or she is able to take food by mouth.
Will I be able to help care for my baby after surgery?
Yes. Ask your baby's nurse about ways to interact with and care for your baby.If you had planned to breastfeed your baby, you can start pumping your breasts and freezing the breast milk while you are still in the hospital. A lactation consultant can assist in answering your questions. Your milk will be frozen and stored in the NICU until your baby is ready for it. The NICU has breast pumps and private rooms available to you when you are visiting. You can bring in pictures, small toys, booties, and blankets for your baby while he or she is in the NICU.
When can my baby go home?
Your baby will go home when he or she can eat enough to maintain and gain weight and breathe sufficiently. The length of stay for a baby with CCAM varies depending on their initial course. If the cyst(s) is large, involves more that one lobe or is bilateral (involves both lungs) and requires immediate intervention and surgery, the stay will be longer. The average stay for this course of care can range from 4-12 weeks. This is compared to a baby who has milder symptoms, or is able to wait two to six months for surgery. Their average stay can range from a few days in the newborn nursery to one or two weeks in the NICU. If there are associated anomalies, (more common with Type II CCAM) this can prolong or complicate the length of stay as well, no matter the size of the CCAM.
What is my baby's long-term prognosis?
The long-term outcome for infants who have the cyst(s) removed is excellent. This is especially true when there are no other anomalies and hydrops is not present. After the cyst(s) is removed, the lungs grow to compensate for the part that was removed. These children usually have no limitations on their activities and have no increased risk for respiratory complications. However, if the CCAM is not removed, there is an increased risk of it becoming cancerous.
Learn more about the Pulmonary Clinic at Children's Hospital of Wisconsin.