Extralobar bronchopulmonary sequestrations (ELS) and bronchogenic cysts are pulmonary congenital anomalies arising from ventral foregut malformations. Although uncommon, foregut malformations frequently occur together. Intralobar bronchopulmonary sequestrations (ILS), however, are rarely associated with bronchogenic cysts or other congenital lesions. This phenomenon raises controversy whether the origin of ILS is congenital or acquired. We present three cases of ILS occurring with a bronchogenic cyst, supporting that it is a congenital, not acquired lesion.CASE PRESENTATION: Case 1: 47-year-old woman presents with recurrent right lower lobe pneumonia since early adulthood. She was a non-smoker, denied tuberculosis exposure or risk factors for HIV and aspiration. Chest radiographs (CXR) revealed a right lower lobe opacity, which had been present on prior images. Computed tomography (CT) showed a right posterior basal infiltrate and 2-cm mediastinal cyst. An aberrant aortic branch directly feeding the posterior basal segment was identified. She was diagnosed with an ILS and underwent surgical resection. Pathology confirmed the cyst-like structure to be a bronchogenic cyst.Case 2: 44-year-old, asymptomatic woman referred for a mass incidentally noted on CXR. She was a non-smoker. Review of systems was unremarkable. CXR showed a 3-cm, well-circumscribed mass in the right lower lobe. CT revealed consolidation of the medial basal segment and 2.7-cm cystic lesion with mediastinal involvement. An aberrant branch of the aorta supplying this segment was identified. She was diagnosed with an ILS and underwent resection. Pathology confirmed the lesion to be a bronchogenic cyst.Case 3: 39-year-old, asymptomatic female referred for PPD-conversion. Screening CXR revealed a 3-cm superior mediastinal mass and right lower lobe infiltrate. Sputum was negative for acid-fast bacilli. Subsequent CT showed a 3.2-cm mediastinal cyst and an aberrant artery branching from the aorta, supplying a consolidated right posterior basal segment. ILS was diagnosed with subsequent resection of the cyst and right lower lobe. The mass was confirmed to be a bronchogenic cyst on pathology.DISCUSSION: Bronchogenic cysts are congenital anomalies arising from the ventral foregut. They are typically located in the mediastinum and commonly present with other congenital malformations. Bronchopulmonary sequestrations are congenital malformations of non-functioning pulmonary tissue that have inadequate communication with the tracheobronchial tree. They also derive from the ventral aspect of the primitive foregut resulting in aberrant development of the tracheobronchial tree. There are two forms of sequestration, extra and intralobar. ELS are associated with other congenital, foregut malformations in 60% of cases, commonly diaphragmatic hernias and bronchogenic cysts. However, congenital anomalies are rarely associated with ILS, leading to the theory that these may be acquired lesions, resulting from chronic inflammation or recurrent infections. In the three presented cases, an ILS was associated with a congenital bronchogenic cyst. Two were not associated with prior infections, suggesting that one anomaly was not the result of the other. The associated cyst supports that ILS is a congenital malformation and not an acquired lesion resulting from recurrent infections.Sequestrations are supplied by aberrant systemic arteries. Demonstration of this vessel confirms the diagnosis and guides surgical resection. Angiography is considered the gold standard. However, newer, less-invasive imaging techniques are equally effective; including CT angiogram, Doppler ultrasound and magnetic resonance angiography.
Although uncommon, ILS can be associated with bronchogenic cysts, further supporting the theory that these are congenital, foregut malformations and not acquired lesions. CT angiography is an invaluable diagnostic tool that can both demonstrate the aberrant arterial supply and identify other anomalous lesions.
C.J. Lettieri, None.