Recurrent pneumonia in a young adult

Pulmonary sequestrations are rare lesions divided into intralobar and extralobar varieties. Intralobar and extralobar sequestrations are distinguished by the lack of an investing pleural envelope surrounding the former. Furthermore, the typical ages of presentation and clinical manifestations of the 2 lesions differ: intralobar sequestrations present as recurrent pulmonary infection in young adults, whereas extralobar sequestrations are usually incidentally detected during the neonatal period and are often associated with other congenital anomalies. Additionally, intralobar sequestrations are usually drained by the pulmonary venous system, whereas extralobar sequestrations are usually drained by the systemic venous system. Intralobar sequestrations usually present as a lower lobe mass, but areas of cavitation, cystic change, or air trapping are commonly encountered as well. The aberrant systemic arterial supply of intralobar sequestrations from the descending thoracic or upper abdominal aorta is usually readily demonstrable with helical computed tomography angiography. Pulmonary venous drainage is also usually readily visible. Extralobar sequestrations usually present as lower lobe masses without air. The aberrant arterial supply to the lesion is readily visible and allows extralobar sequestration to be distinguished from other causes of thoracic masses in the neonate. Intralobar sequestrations are usually treated surgically. Although extralobar sequestrations may not require surgery, they are often resected during the course of treatment of other congenital anomalies.