Background/purpose: The natural history of parenchymal lung lesions such as congenital cystic adenomatoid malformation (CCAM) and pulmonary sequestration (PS) has been altered by the advent of antenatal ultrasonography. Initial reports were characterized by a high (about 30%) incidence of adverse features (eg, hydrops) and a poor outcome and did not accord with our recent experience. The authors have reviewed the outcome of fetuses that had been diagnosed in a large tertiary referral fetal medicine unit with the aim of delineating current experience. The term cystic lung disease was used throughout to avoid unjustifiable histologic precision.
Methods: The scans of all fetuses that had been diagnosed with cystic lung disease between January 1995 and July 2001 were reviewed. The outcome of each pregnancy was established, and, where possible, all infants underwent appropriate investigations, including thoracic computed tomography (CT) scans.
Results: Sixty-seven fetuses had a cystic lung abnormality diagnosed from January 1995 to July 2001. The median (range) age at diagnosis was 21 (19 to 28) weeks. The lesion was right sided in 29 (43%), left in 36 (54%), and bilateral in 2 (3%); it was characterized as dominantly macrocystic in 27 (40%), microcystic in 35 (52%), and mixed in 5 (8%). Mediastinal shift was present in 30 fetuses (45%). Severe signs of fetal distress (eg, hydrops) were present in 5 fetuses (7%). Antenatal intervention was performed in 4 fetuses (thoraco-amniotic shunts [n = 3] and percutaneous intrauterine laser therapy [n = 1]). Sixty-four (96%) of the fetuses were born alive. There was 1 termination of pregnancy and 2 intrauterine deaths (all severe microcystic lesions). Forty-two infants (63%) underwent thoracotomy and appropriate excisional surgery at a median of 7.5 months (range, 1 day to 34 months). Two infants (which included the fetus having intrauterine laser therapy) died early in the postnatal period. Both were large microcystic lesions and had antenatal features of severe fetal distress. Twelve infants were investigated in the postnatal period but did not undergo surgery. Ten infants were not appropriately investigated or were lost to follow-up. Histologic examination showed definitive diagnostic features of CCAM (n = 25) or PS (n = 6). Other lesions with hybrid features of both were also seen (n = 11). There was a degree of correlation between antenatal ultrasound features (size of cyst [P =.03], in-utero behavior [P =.06], mediastinal shift [P = 0.05]) and the need for surgery but not with the final histologic diagnosis. Surgical excision was required in 45% of lesions showing late-gestation "resolution."
Conclusions: Antenatally diagnosed "cystic lung disease" has an excellent prognosis in the absence of signs of severe fetal distress. The need for surgery should be based on appropriate postnatal investigations (eg, CT scans), rather than on antenatal behavior.