Pulmonary artery aneurysms are rare thoracic vascular lesions. They may result from a variety causes, including congenital cardiovascular disease, infections, noninfectious inflammatory diseases, trauma and metabolic and idiopathic etiologies. The clinical presentation of pulmonary artery aneurysms is frequently nonspecific and is often dominated by underlying disease. Pulmonary artery aneurysms often present as solitary nodules or masses on chest radiography, and therefore a large differential diagnosis is often required. One circumstance in which pulmonary artery aneurysm should be specifically sought is the intensive care unit patient that develops a nodule near the pulmonary hilum at the site where a pulmonary arterial catheter tip was located. Cross-sectional imaging, particularly thoracic computed tomography, often allows a specific diagnosis of pulmonary artery aneurysm. Pulmonary artery aneurysms may be treated surgically, although catheter-based therapy with coils or detachable balloons is now usually the treatment of choice.