From the archives of the AFIP - Intralobar sequestration: Radiologic-pathologic correlation

Intralobar sequestration accounts for 75% of pulmonary sequestrations. The lesion consists of lung tissue that lacks normal communication to the tracheobronchial tree, has systemic arterial supply, and shares the pleura of the parent lobe. The majority of intralobar sequestrations are probably acquired lesions, Patients usually present before the age of 20 years with recurrent infection. At pathologic examination, intralobar sequestration is characterized by inflammation and fibrosis. At radiologic examination, intralobar sequestration typically appears as a consolidation or mass, with or without cavitation, within a lower lobe. In many cases, cystic change may be present within the affected lobe, Identification of a systemic arterial supply supports the diagnosis. Patients are treated with surgical excision, and prognosis is favorable.