Congenital cystic adenomatoid malformation (CCAM), a type of lung tumor, is benign, but can grow so large during pregnancy that the fetus eventually dies of cardiovascular failure. In such cases the only option for preventing intrauterine death of the fetus is prenatal surgical removal.
These malformations are visible in ultrasound scans from about mid-pregnancy. Where the option of intrauterine surgery is being considered, an MRI scan is performed for more detailed diagnosis.
Prenatal intervention is indicated as soon as the fetus shows any signs of incipient cardiovascular failure. The tumor, which by this time is usually huge, is removed by open surgery. This returns the fetus to cardiovascular normality and enables its lungs to grow essentially without hindrance.
Though the fetuses in whom this operation is performed are severely ill, roughly two-thirds can be expected to survive this major and traumatic operation and show adequate lung function after birth. Provided that no other serious problems arise later in pregnancy or after birth, the child’s prognosis for normal development is favorable.