Background: A 22-year-old pregnant woman was referred to our radiology clinic for routine obstetric ultrasound (US) examination. The fetus was in the 27th week of gestation. US examination showed numerous cystic lesions varying in size from 1 cm to 4 cm in the left lung surrounded by hyperechogenic solid tissue. The left lung was large, shifting the heart and mediastinum to the right and the diaphragm inferiorly.The lingula and the inferior lobe of the left lung were collapsed. According to the age of gestation excess of amnionic fluid was observed. The other organ systems were normal. After delivery, the fetus developed dyspnea, tachypnea and cyanosis.The newborn reflexes were weakened. The baby was followed up with chest X-rays and supported for respiration when necessary. Since dyspnea was getting worse, the baby underwent left upper lobectomy with preservation of the lingular segment on its 3rd day post-term.