**2.2. Ultrasound diagnosis**

CCAM ultrasound diagnosis is used for pointing out a cystic or solid lung tumor growth with the absence of systemic Doppler vasculature (**Figure 1**).

**Figure 1.** CCAM microcystic, parasagittal view: arrow—lung mass, line—diaphragm.

It is possible to highlight the vascular flow of the lesion that comes from a branch of the pulmonary artery. The use of color Doppler is mandatory to highlight the absence of systemic vasculature and the presence of pulmonary vasculature for CCAM. From the ultrasound point of view, CCAM will be classified in macrocystic and microcystic (**Figures 2**–**4**).

Both the macrocystic form and the microcystic form can cause fetal hydrops and mediastinal shift (**Figure 5**).

The macrocystic types are rarely accompanied by fetal hydrops. The size of the lesion determines whether a fetus will develop hydrops or not [9]. Large scale macrocystic lesions cause mediastinal shift and cardiac decompensation, accompanied by increased venous central pressure, followed by the appearance of the fetal hydrops (**Figure 6**).

What is important to emphasize, is that the degree of the mediastinal shift has no predictive value for the appearance of the hydrops.

It should be underlined that there are CCAM hybrid lesions which refer to the presence of both pulmonary and systemic circulation that originates directly from the descending aorta [10].

The ultrasound differential diagnosis will consider the following: congenital diaphragmatic hernia (CDH), bronchopulmonary sequestration (BS), pericardial teratoma, enteric or bronchogenic cysts, bronchial atresia, esophageal duplication, neuroblastoma, brain heterotopia.

The differential diagnosis from CDH is not easy. The macrocystic form of CCAM can be confused with CDH left-sided; the intrathoracic stomach may resemble the macrocystic form. Highlighting intestinal peristalsis or emptying the herniated stomach can yield the diagnosis in favor of CDH. In addition, the size of the abdomen is normal, and the abdominal organs are in the normal position in case of CCAM (**Figures 7** and **8**).

**Figure 2.** CCAM macrocystic: white arrow—lung cyst.

**Figure 1.** CCAM microcystic, parasagittal view: arrow—lung mass, line—diaphragm.

the absence of systemic Doppler vasculature (**Figure 1**).

• The lack of maturation of the bronchial tissue during the pseudoglandular stage of pulmo-

• Focal pulmonary dysplasia with hamartomatous development at the terminal bronchioles [2]

The estimated incidence is of 1 in 25,000 births, up to 1 in 30,000 births [4]. Most ultrasound detected CCAM lesions are unilateral and only 2–3% of them are bilateral and they are more frequently encountered in male fetuses [5]. In the case of unilateral lesions, a single lobe is usually involved and in rare situation it is the whole lung. Vascularization of the multicystic mass comes from a branch of the pulmonary artery. Recently, Stocker has classified CCAM in 5 types, depending on the group of airways involved: Type 0, the lesion is bronchial. Type 1, the lesion is bronchial/bronchiolar. Type 2, the lesion is bronchiolar. Type 3, the lesion is bronchiolar/alveolar. Type 4, the lesion is peripheral [6, 7]. A more practical classification is that which considers the ultrasound antenatal aspect, proposed by Adzick [8] and which describes the lesions as macrocystic or microcystic. Thus, CCAM has the following classification: Macrocystic type I with single or multiple cysts larger than 2 cm in diameter, CCAM type 2 with multiple cysts smaller than 2 cm and larger than 0.5 cm in diameter and type 3 with multiple cysts, less than 5 mm in size and with a hyperechogenic aspect. By advancing Adzick's classification, a simpler ultrasound classification was established by Wilson [9]. Thus, the ultrasound appearance is a cystic variant and a solid (or microcystic) variant. The cystic variant is multilocular lesions with cysts of various sizes from a few millimeters to 10 cm. The solid microcystic variant comprises a

CCAM ultrasound diagnosis is used for pointing out a cystic or solid lung tumor growth with

nary development, which is between the 5th and 6th week of gestation [2]

• Secondary to the airway obstruction [3]

166 Congenital Anomalies - From the Embryo to the Neonate

hyperechogenic mass.

**2.2. Ultrasound diagnosis**

**Figure 3.** CCAM microcystic: arrow—lung mass, star—normal lung.

Bronchogenic cysts are uniloculated, rarely multicystic, located adjacent to the bronchus, but difficult to distinguish from the macrocystic form of CCAM. Pericardial teratoma may contain large cysts but they are usually associated with the pericardial fluid. The main differential diagnosis of microcystic form of CCAM is with BPS and CDH right

**Figure 6.** Fetal hydrops: arrow—stomach and star—ascites.

**Figure 5.** CCAM microcystic: arrow—lung mass, circle—cardiac shift.

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**Figure 7.** Differential diagnosis CCAM versus CDH left.

**Figure 4.** CCAM microcystic: white line—enhancement of diaphragm.

**Figure 5.** CCAM microcystic: arrow—lung mass, circle—cardiac shift.

**Figure 6.** Fetal hydrops: arrow—stomach and star—ascites.

Bronchogenic cysts are uniloculated, rarely multicystic, located adjacent to the bronchus, but difficult to distinguish from the macrocystic form of CCAM. Pericardial teratoma may contain large cysts but they are usually associated with the pericardial fluid. The main differential diagnosis of microcystic form of CCAM is with BPS and CDH right

**Figure 4.** CCAM microcystic: white line—enhancement of diaphragm.

**Figure 3.** CCAM microcystic: arrow—lung mass, star—normal lung.

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**Figure 7.** Differential diagnosis CCAM versus CDH left.

**2.3. Prognostic**

could need a surgical postnatal resection.

**2.4. Prenatal management**

**Figure 9.** CCAM microcystic intraoperator view.

perinatal demise being the most frequent outcome, around 100%.

HC. If CVR is more than 1.6 the incidence of hydrops is 75%.

large masses and low for small-medium masses (**Figure 9**).

CCAM is not associated with syndromes, the risk of chromosomal anomalies being extremely low. In the absence of hydrops, the long-term outcome of the fetuses with CCAM is good. The incidence of hydrops is 10% in cases of a large cystic mass [12]. Termination of pregnancy before 24-week gestation remains an option for the couple. In cases of prenatal diagnosis of CCAM, the parents should be counseled about the good prognosis even though the CCAM

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The most important factor for prognosis is the presence of hydrops, which is the most important predictor of poor prognosis. If hydrops is present, the chances of survival are very low,

Another prognostic factor has been established with the use of 3D ultrasound, in determining the CAM volume ratio, (CVR) [13]. This parameter is calculated by dividing the volume of CCAM by the HC (head circumference). That is diameter (L × AP × T) × 0.52 divided by the

It is important to emphasize that the mass has an important potential growth between 20 and 26-week gestation, then there is a plateau, and afterwards the mass tends to regress. Thus, since the volume of a mass is not expected to increase after 26 weeks, and if there is no hydrops, then it is unlikely for the hydrops to appear after 26-week gestation. In cases of large masses, it is recommended to plan delivery in a tertiary center because of the risk of lung hypoplasia, cardiovascular decompensation and high mortality. The postnatal risk is high for

Prenatal fetal therapy is indicated in cases that develop hydrops or cardiac failure.

**Figure 8.** Differential diagnosis CCAM versus CDH right: white line—heart shift.

associated with liver herniation. Basically, the main distinguishing ultrasound element is that in BPS, vascularization originates from the systemic circulation, primarily the direct branch from the descending aorta, which can be easily demonstrated with Doppler color or HD-flow Color Doppler [9, 10]. The differentiation criteria between CCAM and BPS are shown in **Table 1**.

Therefore, the identification of the systemic circulation for a lung tumor mass is pathognomonic for BPS. Recently, Cass described 6 cases of CCAM that also had systemic vasculature and specific histological elements for BPS and CCAM, so these lesions were called hybrid lesions [10]. CDH right with hernia of the liver determines a significant mediastinal shift and secondary pulmonary compression. The highly hyperechogenic aspect of the CCAM microcystic form requires the differentiation from neuroblastoma as well. The association of CCAM with extrapulmonary abnormalities ranges from 0 to 26%, renal agenesis or dysgenesia being the most common associations [11, 12].


**Table 1.** Differential diagnosis CCAM versus BPS.
