LearningRadiology - Sequestration

Bronchopulmonary Sequestration

Congenital malformation of the primitive foregut in which a part of the lung is not attached to the rest and gets its blood supply from a systemic artery

Lies within the same visceral pleura as the lobe in which it occurs
Non-functioning — intralobar sequestrations are closed systems not communicating with the tracheobronchial tree unless infected
Gets its arterial supply from the aorta, most commonly descending thoracic aorta
Venous drainage is almost always to the pulmonary venous system (left-to-right shunt)
In about 2/3 of cases, the sequestration is in the left lower lobe, posterior segment; in the remainder it is in the right lower lobe, posterior segment
Not usually associated with other anomalies
Frequently recognized in adulthood because of pneumonia

X-ray

When not infected, they appear as solid masses in the left lower lobe usually touching the diaphragm
If infected and communicating with the bronchial tree, they may be cystic, air-containing with fluid levels
May be obscured by surrounding pneumonia in normal lung
Classically, a bronchogram shows the bronchi draped around the mass, a distinctive finding

Develops as an accessory lung contained within its own pleura
Related to the left hemidiaphragm in 90% of cases
It usually drains via the systemic venous system – the IVC, azygous or hemiazygous
The systemic arterial supply is commonly from the abdominal aorta
Associated with other anomalies (congenital diaphragmatic hernias are common)

X-ray

· Since it is enveloped in its own pleural sac, it rarely gets infected so it almost always presents as a homogeneous soft tissue mass

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