Behcet's disease is a rare form of vasculitis of obscure etiology. Any large or small artery, vein, or organ may be involved in an unpredictable combination. Intrathoracic manifestations of Behcet's disease consist mainly of thromboembolism of the superior vena cava and/or other mediastinal veins; aneurysms of the aorta and pulmonary arteries; pulmonary infarct and hemorrhage; pleural effusion; and, rarely, myocardial or pericardial involvement, cor pulmonale, and mediastinal or hilar lymphadenopathy. Chest radiography is the best diagnostic method for evaluating thoracic involvement in Behcet's disease. Because aneurysms may develop at the arterial puncture sites and veins may be quickly thrombosed after injection of contrast material, angiography and venography should be avoided whenever possible. Although no comparative studies are available, CT and MR angiography appear to be imaging techniques of choice for evaluating vascular involvement. Pulmonary parenchymal alterations depicted on CT scan have not been fully explored.