Antenatal sonographic findings associated with unilateral pulmonary agenesis

Unilateral pulmonary agenesis is a rare anomaly that has a relatively frequent association with other congenital malformations. Prognosis depends in part upon associated anomalies and whether the right or left lung is involved. The prenatal sonographic findings of this defect share some similarities with those of other intrathoracic lesions or congenital diaphragmatic hernia.

Our patient had a twin gestation complicated by early discordant growth and hydramnios. The smaller fetus had cardiac dextroposition, abnormally echogenic left lung tissue, and a flattened but clearly visible left hemidiaphragm. No abdominal viscera were seen in the thoracic cavity. Postnatally, this infant was found to have agenesis of the right lung, a tracheoesophageal fistula, and pyloric stenosis.

The diagnosis of unilateral pulmonary agenesis should be considered in a fetus with the sonographic findings of a shift of the mediastinal structures, echogenic lungs, and an intact diaphragm.