Large vessel pulmonary arteritis mimicking chronic thromboembolic disease

Chronic obstruction of pulmonary arteries can be due to a variety of disease processes, including chronic thromboembolic disease, fibrosing mediastinitis, or neoplasia. Large vessel arteritis is another unusual cause of pulmonary artery obstruction and can be difficult to distinguish from the above-listed etiologies. We present four patients referred to our institution with the provisional diagnosis of chronic thromboembolic pulmonary hypertension who were subsequently diagnosed with Takayasu's arteritis involving the pulmonary arteries. We review the historical, physical examination, and radiologic characteristics that help distinguish Takayasu's arteritis from chronic thromboembolic disease.