Congenital pulmonary airway malformation

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Congenital pulmonary airway malformation
Classification and external resources
Computerized tomography of the chest of a patient with congenital cystic adenomatoid malformation.jpg
ICD-10 Q34.8 (EUROCAT Q33.80)
ICD-9 748.4
DiseasesDB 32408
eMedicine ped/534 radio/186
MeSH D015615

Congenital pulmonary airway malformation (CPAM), formerly known as congenital cystic adenomatoid malformation (CCAM), is a congenital disorder of the lung similar to bronchopulmonary sequestration. In CPAM, 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 CPAM is unknown. It occurs in approximately 1 in every 30,000 pregnancies.[1]

In most cases the outcome of a fetus with CPAM is very good. In rare 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 CPAM can be life-threatening for the fetus. CPAM can be separated into five types, based on clinical and pathologic features.[2] CPAM type 1 is the most common, with large cysts and a good prognosis. CPAM type 2 (with medium-sized cysts) often has a poor prognosis, owing to its frequent association with other significant anomalies. Other types are rare.[3]

Diagnosis[edit]

CPAM 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.

CPAMs 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.

CPAMs 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."

Treatment[edit]

In most cases, a fetus with CPAM is closely monitored during pregnancy and the CPAM is removed via surgery after birth.[4] Most babies with a CPAM 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 CPAMs. Some pediatric surgeons can safely remove these lesions using very tiny incisions with the aid of a telescope (thoracoscopy). However, some CPAM patients live a full life without any complication or incident. It is hypothesized that there are thousands of people living with an undetected CPAM. Through ultrasound testing employed in recent years, many more patients are aware that they live with this condition. Rarely, long standing CPAMs 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 CPAM. If non-immune hydrops fetalis develop, there is a near universal mortality of the fetus without intervention. Fetal surgery can improve the chances of survival to 50-60%. Recently, several studies found that a single course of prenatal steroids (betamethasone) may increase survival in hydropic fetuses with microcystic CPAMs to 75-100%.[5][6] 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.

Popular culture[edit]

In season 3 of the television show House, episode 17 ("Fetal Position") features a pregnant woman whose fetus is ultimately diagnosed with CPAM. In the climax of the episode, the team performs open fetal surgery to remove the cysts.[7]

References[edit]

  1. ^ http://synapse.koreamed.org/Synapse/Data/PDFData/0003TRD/trd-72-501.pdf
  2. ^ Nihal Kilinç et al, "Congenital Pulmonary Airway Malformation: Case Report". Perinatal Journal, vol. 15, issue 1 (April 2007)
  3. ^ Robbins and Cotran, Pathologic Basis of Disease 7th ed.
  4. ^ Ehrenberg-Buchner, S; Stapf, AM; Berman, DR; Drongowski, RA; Mychaliska, GB; Treadwell, MC; Kunisaki, SM (Nov 15, 2012). "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. 
  5. ^ 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. 
  6. ^ 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. 
  7. ^ Fetal Position (House)

External links[edit]