This is the most common cause of cystic lung abnormality in children. The true incidence is not known but is thought to range between 1:4000- 1:8000 births. These may present antenatally (during your pregnancy) on routine ultrasound screening, following birth or at any time during childhood. The range of presentations may be related to the size of the CPAM or complications arising in the CPAM. Most often however children will have very few symptoms oreven none. Complications that may arise in the CPAM are secondary to compression of normal lung or heart by the lesion, infection (thought to be 5-10%), and rupture of the lesion causing a pneumothorax (leakage of air around the lung). Most of these complications are uncommon. There has been a reported association between CPAM and malignancy in later life. This link however is tenuous and unproven. Treatment depends on the size, and consistency of the CPAM as well as the likelihood for complications.