Approximately 50% of all congenital lung malformations are pulmonary and me
diastinal bronchogenic cysts (BC). Therefore, their diagnosis and managemen
t is of clinical importance. Usually asymptomatic in the first months of li
fe, bronchogenic cysts are frequently clinically inapparent even adulthood.
Early diagnosis and elective surgery can prevent late complications such a
s pneumothorax, pulmonary hypertension, and recurrent infections; prognosis
after surgery is excellent. If mediastinal shifting is present, fetal thor
acocentesis is indicated to prevent cardiovascular insufficiency. We report
a case of a prenatally diagnosed intrapulmonary BC of the right lung. Foll
owing in utero thoracocentesis of the cyst and transient spontaneous regres
sion postnatal on set of severe clinical symptoms due to rapidly developing
hyperinflation and mediastinal shifting within the first days of life requ
ired early surgical intervention.