FLASH CARD: Pulmonary Sequestration

• Extralobar sequestrations have systemic arterial supply (usually from the aorta) as well as systemic drainage (usually into the IVC, azygous, hemiazygous, or the portal vein), thus creating a L to R shunt (functionally it is an AVF).  90% are related to the left hemidiaphragm.  It possesses its own pleural investment and 30% are associated with diaphragmatic hernias.  They may also communicate with the GI tract.   They are congenital
• Intralobar sequestrations occur most commonly in the lower lobes (usually the left) and are infrequently associated with other anomalies.  Their arterial supply is via systemic circulation (usually the aorta or a branch) but their drainage is via the pulmonary veins, creating a L to L shunt.