Congenital Cystic Adenomatoid malformation of Lung (CCAM)

Congenital cystic adenomatoid malformation (CCAM) or congenital pulmonary airway malformation (CPAM) are benign (non-cancerous) lung lesions. CCAM appears before birth as a cyst or mass in the babies chest, which is made up of abnormal lung tissue that does not function properly, but still continues to grow in size. CCAM’s usually arises from one lobe of the lung. Lower lobes are the most common sites for CCAM although it can involve any lobe. CCAM lesions have an equal left- and right-sided incidence in the lungs.

What are the types of CCAM?
CCAM cases can be classified into several types based largely on their gross appearance. Type I (the macrocystic or large cyst type) accounts for over 50% of all cases, consisting of single or multiple cysts, which are usually large in size (2 to 10 cm in diameter) and few in number (one to four). Type II has smaller uniform cysts. Type III is not grossly cystic and more solid. Some CCAM have an abnormal connection to a blood vessel from an aorta and these are referred to as "hybrid lesions", a combination of CCAM with sequestration.

What are the symptoms of CCAM?
In the current era children with CCAM are diagnosed before birth by an antenatal ultrasound scan. In majority the CCAMs either shrinks or are small enough and does not cause any problems with fetal growth or pregnancy. However, some large CCAM can cause serious problems and displacement of the heart to the other side leading to fetal hydrops. Most of these babies will not have any symptoms at birth, if the CCAM is small. Babies with a large CCAM have fast breathing, difficulty in breathing and oxygen need. Some babies may not be having any significant symptoms at birth, but might present with recurrent episodes of pneumonia with the CCAM getting infected.
Congenital Cystic Adenomatoid malformation of Lung (CCAM)

In developing countries like India where antenatal care is not uniform, most cases with CCAM are diagnosed later. Symptoms will vary depending on the size of the CCAM. Repeated pneumonia at the same site of the lung is the most common presentation in children. In some cases symptoms may not be apparent until they are adults.

How do we diagnose a child with CCAM?
Children who have CCAM in antenatal scans but have no significant symptoms get a CT scan chest at around 3 months of age. Many children present with repeated episodes of pneumonias. Diagnosis can be difficult in such cases. Other causes of repeated pneumonias should be considered in children, including cystic fibrosis, immune deficiency problems, tuberculosis etc.

How are children with CCAM treated? Do all patients with CCAM require surgery?
There is no controversy that a surgery will be required in children who have symptoms or large CCAM. There is still a controversy whether small CCAM not leading to any symptoms should be operated or can be left alone. The reasons cited for getting a surgery are a small risk of infection and a risk of developing cancer on the CCAM. Surgery is usually scheduled at 6 months of age.

Many experts believe that the risk of infection is negligible in children with small CCAM and recent literature does not suggest that there is a significant risk of cancer. Hence, many centres have started to adopt conservative treatment.

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