From the archives of the AFIP. Extralobar sequestration: radiologic-pathologic correlation.

Extralobar sequestration

“…1 Sequestrations are believed to arise from supernumerary lung buds that arise from the primitive foregut in about the fifth week of gestation. 2,3 Two types are described: as intralobar sequestration and extralobar sequestration (ELS). Extralobar sequestration comprises B25% of all sequestrations and is covered by a separate pleural investment.…”

“…4 The venous drainage of ELS is usually through the systemic circulation into the hemiazygos veins, azygos veins, inferior vena cava or portal vein. 2 Approximately 65% of ELS are located on the left side and 70% of these are located between the left lower lobe and the diaphragm. 2 Approximately 10% of ELS are located below the diaphragm in the left suprarenal retroperitoneum.…”

“…2 Approximately 65% of ELS are located on the left side and 70% of these are located between the left lower lobe and the diaphragm. 2 Approximately 10% of ELS are located below the diaphragm in the left suprarenal retroperitoneum. 5 These abdominal retroperitoneal ELS need to be differentiated from other suprarenal masses, especially neuroblastoma.…”

“…8,9 Most cases of postnatally detected ELS are symptomatic, and are usually detected within the first 6 months of life. 2 At birth, presenting signs of ELS include nonimmune hydrops and large pleural effusions, believed to be because of venous obstruction from the sequestration inutero. 8 Later symptoms include pneumonia, cough, cyanosis, recurrent infection and high output congestive heart failure.…”

Pulmonary Sequestration

“…These are commonly found between the diaphragm and the lower lobe of the lung. 2 The blood vessels to extralobar sequestrations are often from the thoracic or abdominal aorta. 3 Sequestrations usually present before the age of 20.…”