Intralobar pulmonary sequestration: a clinical and pathological spectrum.

Pulmonary sequestration is a mass of abnormal pulmonary tissue that does not communicate with the tracheobronchial tree and is supplied by an anomalous systemic artery. Whereas extralobar sequestration is clearly congenital, intralobar sequestration, which frequently presents in older children with pathological findings showing acute and chronic inflammation, may have an acquired origin secondary to frequent infections. Several large autopsy series support an acquired etiology of intralobar sequestration. Four cases of intralobar sequestration are presented that demonstrate a spectrum of inflammatory change that support its congenital, rather than acquired origin. Case 1 was a newborn who presented with tachypnea and a right lower lobe density. Resection at 3 weeks of age showed no inflammation in the sequestration specimen. Case 2 presented as a newborn infant with congestive heart failure. Pulmonary sequestration was confirmed by arteriogram. Resection at 3 months of age showed chronic inflammation. Case 3 presented at 7 months of age with chronic pneumonia. The resected specimen demonstrated moderately severe acute and chronic inflammation. Case 4 presented as a 6 year old. The operative specimen showed extensive bronchiectatic changes with marked acute and chronic inflammation. These cases support the congenital origin of intralobar sequestration and suggest a temporal progression from no inflammation to severe acute and chronic inflammation.