• CCAM / CPAM Details

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    Newborns with CCAM / CPAM should be evaluated in the nursery to confirm the prenatal diagnosis and to exclude other health conditions.

    A chest CT scan will confirm the diagnosis and define the anatomy. Complete resection of the CCAM / CPAM is the preferred treatment. The reasons for recommending resection for CCAM / CPAM, which are otherwise asymptomatic, are infection and neoplastic transformation.

    All malformations have a connection with the tracheobronchial tree, which may predispose to bacterial contamination. Malformations can undergo malignant transformation. The youngest case reported was a patient only 13 months of age.

    While some recommend observation for asymptomatic CCAM / CPAM, we routinely recommend they be resected. These malformations remain a health concern for as long as they are present.

    Unfortunately, we do not know how to identify which malformations will become infected or develop a tumor before the problem actually occurs.

    The indications for fetal intervention depend on the type of lesion, whether solid or cystic, and the development of hydrops. In malformations with a dominant cyst, the development of hydrops indicates the need for a thoracentesis or thoracoamniotic shunt to decompress the fluid within the cysts. Thoracentesis alone, however, cannot provide the continuous decompression that thoracoamniotic shunting can. In the rare instances of Congenital Cystic Adenomatoid Malformation (CCAM / CPAM) with a single or a couple of large cysts responsible for hydrops, thoracoamniotic shunting is the treatment of choice.

    The first uses of thoracoamniotic shunting in fetuses with CCAM / CPAM were reported in 1987 by Nicolaides and associates and separately by Clark. Percutaneous placement of a thoracoamniotic shunt in a fetus of 20 weeks' gestation decompressed a large type I Congenital Cystic Adenomatoid Malformation, according to Clark, and resolved both the mediastinal shift and hydrops. The infant was successfully delivered at 37 weeks of gestation and then underwent uneventful resection of the CCAM / CPAM. Six subsequent cases of thoracoamniotic shunting in CCAM / CPAM have been reported by Adzick and coworkers, with a good outcome in five of the six fetuses treated, although the survivors had respiratory insufficiency and some have required ECMO or high-frequency ventilation.

    A more recent study by Wilson et al found that shunting of macrocystic (type I) CCAM / CPAM resulted in a 51 percent reduction in the CAM volume and resolved the hydrops over seven to ten days. Successful shunting prolonged pregnancy into the third trimester and seven of the ten fetuses treated with thoracoamniotic shunting survived. The authors concluded that a thoracoamniotic shunt should be considered as a treatment option for fetuses with macrocystic (type I) CCAM / CPAM with hydrops or a high risk of developing pulmonary hypoplasia (underdeveloped lungs), and failure of less invasive needle aspiration treatment of the macrocyst fluid (thoracentesis) to prevent rapid reaccumulation of the fluid after one to two aspirations.

    Another recent study by Vu et al sought to improve the ability to identify fetuses at especially high risk of developing hydrops because of large CCAM / CPAM. The study focused on large malformations because large size had already been associated with increased risk for developing hydrops. A combination of three features that could be seen by sonogram was associated with hydrops with a large chest mass. These features were: mass-thorax ratio (MTR) of at least 0.56; the predominance of cystic lesions, and inversion or depression of the diaphragm.

    With regard to in utero prognosis, poor outcomes are more common in the type III CCAM / CPAM. These microcystic lesions become enlarged, resulting in hydrops and intrauterine fetal demise. In these later cases open fetal surgery and resection are indicated.

    High risk CCAM / CPAMs (with a CVP of ≥1.6 or hydrops) should be treated with maternal steroids. We have found that in up to 50 percent of patients, the CCAM / CPAM will stop growing. This allows the baby to grow out of hydrops and for the lungs to develop.

    In the case of solid lesions, the development of hydrops manifests by ascites, pleural or pericardial effusions, skin or scalp edema or placentomegaly.

    In some cases, maternal steroids appear to arrest the growth of these lesions. This is sometimes a useful temporizing measure. In patients with large, solid CCAM / CPAM with associated hydrops, open fetal surgery is indicated. Without intervention, CCAM / CPAM associated with hydrops is almost always fatal.

    In experience with 26 cases of open fetal surgery with hydropic CCAM / CPAM, the survival has been 61 percent. The outcomes for fetal surgery for CCAM / CPAM have been improved by careful observation and by intervention at the earliest signs of hydrops.

    In addition, the use of intraoperative echocardiographic fetal monitoring and thoracoabdominal surgical exposure have helped improve outcomes in this surgery. The survival in these cases has increased to 78 percent. Perhaps the best way to improve outcomes in high risk CCAM / CPAM is through close surveillance to identify early signs of hydrops. Too often, patients are referred late in their course presenting with advanced hydrops.

    Cases in which CCAM / CPAM are large but have not resulted in hydrops may require resection during an EXIT procedure.

    In some cases, the CCAM / CPAM is so sufficiently large that the mediastinum is shifted and the lung compressed. Under these conditions, the lungs may not be able to be ventilated. Removing the CCAM / CPAM during an EXIT procedure allows the lungs to function.

    For more information about Congenital Cystic Adenomatoid Malformation diagnosis and treatment, download a list of references.
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