congenital cystic adenomatoid malformation

[Doctors]

Acongenital disorder similar to bronchopulmonary sequestration. In CCAM, usually an entire lobe of lung is replaced by a non-working cystic piece of abnormal lung tissue. This abnormal tissue will never function as normal lung tissue.

In most cases the outcome of a fetus with CCAM is very good. However in a rare few cases the cystic mass grows so large as to limit the growth of the surrounding lung and cause pressure against the heart. In these situations, the CCAM can be life-threatening for the fetus.
DIAGNOSIS;
CCAM on chest radiograph in a newborn. Large cystic changes in the left lung, leading to a mediastinal shift to the right due to their mass effect.
CCAMs are often identified during routine prenatal ultrasonography. Identifying characteristics on the sonogram include: an echogenic (bright) mass appearing in the chest of the fetus, displacement of the heart from its normal position, a flat or everted (pushed downward) diaphragm, or the absence of visible lung tissue.
CCAMS are classified into three different types based largely on their gross appearance. Type I has a large (>2 cm) multiloculated cysts. Type II has smaller uniform cysts. Type III is not grossly cystic, referred to as the "adenomatoid" type. Microscopically, the lesions are not true cysts, but communicate with the surrounding parenchema.
TREATMENT;
In most cases, a fetus with CCAM is closely monitored during pregnancy and the CCAM is removed via surgery after birth. A few fetuses may develop fluid collections within the chest cavity and in those situations a Harrison catheter shunt can be used to drain the fluid into the amniotic fluid. Most babies with a CCAM are born without complication and are monitored during the first few months. Many patients have surgery, typically before their first birthday. However, many CCAM patients live a full life without any complication or incident. It is hypothesized that there are thousands of people living with an undetected CCAM and it is only in recent years that the diagnosis of a CCAM due to a fetal ultrasound, that many patients are aware that they live with this condition.

Very large cystic masses might pose a danger during birth because of the airway compression. In this situation, a special surgical type of delivery called the EXIT procedure may be used.

In rare extreme cases, where fetus's heart is in danger, fetal surgery can be performed to remove the CCAM. If non-immune hydrops fetalis develop, there is a near universal mortality of the fetus without intervention. Fetal surgery can improve the survival percentage up to 50-60%. Recently, several studies found that a single course of prenatal steroids (betamethasone) may increase survival in hydropic fetuses with microcystic CCAMs to 75-100%.[1][2] These studies indicate that large, macrocystic lesions may be treated prenatally without surgical intervention.