Postnatal management of resolving fetal lung lesions

Objectives. Lung lesions are increasingly diagnosed since the advent of routine prenatal ultrasound. These lesions seem to involute in 15% to 30% of cases. Postnatal evaluation is frequently limited, particularly when repeated ultrasound or initial chest radiographs are normal. As careful follow-up or resection may be required, accurate diagnosis is essential. The objective of this study was to determine whether prenatal lung lesions that seem to resolve are still present when evaluated more closely. Methods. We followed 24 cases of prenatally diagnosed lung lesions at our center, using repeated chest radiographs and chest computerized tomography (CT). Results. Some lesions caused mild mediastinal shift, but none showed hydrops fetalis. In 7 cases, the last prenatal ultrasound was negative. In 15 cases, initial postnatal chest radiograph was normal and in only 4 of these, the lesion was seen on later chest radiographs. This apparently high rate of resolution was, however, misleading. In 22 of the 23 cases in which CT was performed, lung cysts or lobar overinflation was clearly demonstrated. Conclusions. Apparent involution of lung lesions on serial prenatal ultrasounds or neonatal chest radiograph can be misleading. We strongly recommend repeated radiographs and chest CT for definitive diagnosis in all cases.