Congenital cystic adenomatoid malformation
|Congenital cystic adenomatoid malformation|
|Classification and external resources|
|ICD-10||Q34.8 (EUROCAT Q33.80)|
Congenital cystic adenomatoid malformation (CCAM) is a congenital disorder of the lung similar to bronchopulmonary sequestration. The disorder is often referred to by another name, congenital pulmonary airway malformation (CPAM). 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. The underlying cause for CCAM is unknown. It occurs in approximately 1 in every 30,000 pregnancies. 
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.
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 parenchyma. Some lesions have an abnormal connection to a blood vessel from an aorta and are referred to as "hybrid lesions."
In most cases, a fetus with CCAM is closely monitored during pregnancy and the CCAM is removed via surgery after birth. 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, because of the risk of recurrent lung infections associated with CCAMs. Some pediatric surgeons can safely remove these lesions using very tiny incisions with the aid of a telescope (thoracoscopy). However, some 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. Rarely, long standing CCAMs have been reported to become cancerous.
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%. These studies indicate that large microcystic lesions may be treated prenatally without surgical intervention. Large macrocyst lesions may require in utero placement of a Harrison thoracoamniotic shunt.
In the 17th episode of season 3 of House entitled "Fetal Position", the primary patient is a pregnant woman whose fetus is ultimately diagnosed with CCAM. In the climax of the episode, the team performs open fetal surgery to remove the cysts. 
- Ehrenberg-Buchner, S; Stapf, AM; Berman, DR; Drongowski, RA; Mychaliska, GB; Treadwell, MC; Kunisaki, SM (2012 Nov 15). "Fetal lung lesions: can we start to breathe easier?". American journal of obstetrics and gynecology 208 (2): 151.e1–7. doi:10.1016/j.ajog.2012.11.012. PMID 23159697.
- Curran PF, Jelin EB, Rand L, Hirose S, Feldstein VA, Goldstein RB, Lee H (2010). "Prenatal steroids for microcystic congenital cystic adenomatoid malformations". J Pediatr Surg. 45 (1): 145–50. doi:10.1016/j.jpedsurg.2009.10.025. PMID 20105595.
- Peranteau WH, Wilson RD, Liechty KW, Johnson MP, Bebbington MW, Hedrick HL, Flake AW, Adzick NS (2007). "Effect of maternal betamethasone administration on prenatal congenital cystic adenomatoid malformation growth and fetal survival". Fetal Diagn Ther 22 (5): 365–371. doi:10.1159/000103298.
- CCAM Treatment at Jackson Fetal Therapy Center Jackson Memorial Hospital-Miami, Florida
- Congenital Cystic Adenomatoid Malformation | UCSF Fetal Treatment Center
- Congenital Cystic Adenomatoid Malformation | Congenital Pulmonary Airway Malformation Radiology and Pathology
- Congenital Cystic Adenomatoid Malformation (CCAM) and Bronchopulmonary Sequestration | Center for Fetal Diagnosis and Treatment | The Children's Hospital of Philadelphia