Pulmonary aneurysms and primary neoplasms of the great vessels are very rare entities; pulmonary aneurysms are commonly associated with congenital heart diseases, and less frequently in atherosclerosis, medial cystic necrosis, trauma, infection, and inflammatory processes. Many patients have pulmonary hypertension, most frequently resulting from pulmonary artery sarcomas mimicking pulmonary thromboembolism. Symptoms are vague. In 30% of cases, rupture and death occur, related to pulmonary aneurysms. We present the case of a patient with a diagnosis of pulmonary artery pleomorphic malignant histiocytoma that presented as a right pulmonary aneurysm thrombosis and a contained rupture of a left pulmonary aneurysm.