Extralobar Pulmonary Sequestration
|Lt. Extralobar Sequestration|
Extralobar sequestration is seen in 15-25% of all sequestrations and approximately 0.5-6% of all congenital malformations of the lung. It is sequestered lung that arises after formation of the pleura and thus has its own pleural covering. Eighty percent occur on the left side, posteriorly. While most cases occur within the thorax, cases have been described within the mediastinum, pericardium or below the hemidiaphragm. The blood supply is from the aorta and venous drainage is through systemic veins in over 80% of cases. Extralobar sequestration occurs more frequently in males with a ratio of 4:1. Approximately 50-60% of patients have associated malformations, the most common being congenital diaphragmatic hernia. Other associated malformations include communications with the esophagus or stomach (T-E fistula), bronchogenic cyst, pericardial defect, congenital heart disease, vertebral abnormalities, megacolon and cystic adenomatoid malformation of the lung. Type II cystic adenomatoid malformation of the lung has been reported in 15-25% of patients with extralobar sequestration.
Sonographically, sequestrations appear as an echogenic solid mass in the left lower thorax. If the lesions are large they may cause mediastinal shift and may cause either polyhydramnios or hydrops or both, likely due to compression of either the esophagus or venous or lymphatic structures. As was mentioned above, the hallmark of this disease is identification of aortic supply and sytemic venous drainage. This can be demonstrated nicely with color Doppler flow imaging. In the past several years there have been numerous reports of resolution of hydrops in patients with sequestration, as well as decreased size of the sequestration, itself. Therefore, while it is appropriate to consider the prognosis poor when hydrops develops in patients with this condition, the parents should be advised that it is not uniformly fatal.
Piccone W, Burt ME. Pulmonary sequestration in the neonate. Chest 97:244-246, 1990
Jones DA, Vill MD and Izquierdo LA. Lung, extralobar intrathoracic sequestration. Fetus 2:6:5-7, 1992
Abuhamad AZ, Bass T, Katz ME and Heyl PS. Familial recurrence of pulmonary sequestration. Obstet Gynecol 87:843-845,1996
daSilva OP, Ramanan R, Romano W, Bocking A and Evans M. Nonimmune hydrops fetalis, pulmonary sequestration, and favorable neonatal outcome. Obstet Gynecol 88:681-683, 1996
Home | Teaching Files | Literature | Bulletin Board