Pulmonary arterial aneurysm

Pulmonary arterial aneurysms (PAA's) refer a focal dilatation of the pulmonary arterial system.

Overall it is considered a rare entity with autopsy prevalence rates of around 1 in 14,000 to 100,000 4-5.

A true pulmonary artery aneurysm results from dilatation of all three layers of  the vessel wall while a pulmonary artery pseudoaneurysm does not involve all layers of the arterial wall. Most of the aneurysms affect the main pulmonary arteries 4.

They can arise from a number congenital as well as acquired pathologies (the latter is considered more common):

  • acquired
  • congenital
    • congenital cardiac anomalies leading to pulmonary arterial hypertension - patent ductus arteriosus is the most common cause
      • increased flow due to left to right shunts
      • increased hemodynamic shear stresses
    • pulmonary valvular and postvalvular stenosis
    • certain pulmonary vasculitides

Radiographic features are nonspecific and they may appear as hilar enlargement or a lung nodule.

CT angiography (CTA) allows much better appreciation of anatomy. Some consider the upper limit of normal diameter of the pulmonary trunk on CT scan as 29 mm and the right interlobar artery as 17 mm 1.

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Article information

rID: 25912
Systems: Vascular, Chest
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Pulmonary arterial aneurysms
  • Aneurysm of pulmonary artery
  • Focal dilatation of the pulmonary arteries
  • Focal dilatation of the pulmonary artery
  • Pulmonary artery aneurysm
  • Pulmonary artery aneurysms

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Cases and figures

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    Case 1: with Behcet disease
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    Case 2: with Behcet disease
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    Case 3: infective aneurysm
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