Pulmonary Sequestration

  • Etiology: lung tissue not connected to bronchial tree or pulmonary artery, comes from accessory lung bud, if it develops early before pleura develops is intralobar, if it develops later after pleura develops is extralobar
  • Imaging: most commonly in lower lobes (left lower lobe), arterial blood supply from subdiaphragmatic aorta, only contain air when infected
    — Intralobar – within visceral pleura, drains via pulmonary veins to left atrium (normal drainage)
    — Extralobar (majority) – outside visceral pleura, drains via systemic veins to vena cava or azygous vein, 10% infradiaphragmatic usually in a left suprarenal location
  • Clinical: present with recurrent infections, 60% of extralobar sequestrations are associated with congenital abnormalities (congenital diaphragmatic hernia, cardiac anomalies, congenital pulmonary airway malformation = hybrid lesion)

Cases of Pulmonary Sequestration

CXR and MRI of pulmonary sequestration
CXR shows a large round opacity in the left lower lobe that abuts the diaphragm. Coronal T1 MRI with contrast of the chest shows a uniformly enhancing mediastinal mass that extends into the retrocrural regions of the chest bilaterally and that has a feeding vessel arising from the aorta.
Gross pathological image of extralobar pulmonary sequestration
Gross pathological images show a right-sided subdiaphragmatic / suprarenal mass similar in appearance to the lung above it (above left). When the aorta was opened (above right), the orifice of an arterial vessel supplying the mass was seen coming off of the aorta just above the tip of the upper hemostat on the right side of the aorta. The relationship of the feeding vessel off of the aorta to the mass is more clearly demonstrated on the specimen image (below).