RESUMO
Pulmonary sequestration is a congenital anomaly of lung in which a portion of lung par-enchyma has no communication with the tracheobronchial tree and receives its blood supply via systemic artery. Sequestration represents a developmental anomaly of tracheobronchial branching with persistence and localized development of a separated branch fragment and retention of its embryonic systemic vascular supply. In the review of the literature, this disease is so rare that only 540 cases were reported worldwide. The anomaly is divided into 2 types; intralobar and extralobar. The ratio of intralobar type and extralobar type is about 3.5 : 1 and intralobar type is more common than the latter in all age groups. The intralobar type is contiguous with normal lung parenchyma and within the same visceral pleural envelope ; in contrast, the extralobar type is enclosed within its own pleural membrane, usually close to a normal lung but separated and discovered most commonly in the left hemithorax with rare cases in the abdominal cavity. Traditionally, this disease has been presented as an incidental lung mass in routine chest X-ray in the postnatal period and with confirmation by aortic angiography, but recently, pulmonary sequestration is diagnosed in the antenatal period along with the development of antenatal ultrasonography. Ultrasonography shows the pulmonary sequestration as a hyperechogenic mass near the diaphragm with posterior echo-free shadow. We have experienced one case of pulmonary sequestration which was found by antenatal ultrasonography and confirmed by operation and histopathologic report in the neonatal period, and we present the case with a brief review of the literatures.