A 66-year-old woman with a history of mitral valve replacement with a Starr-Edwards ball valve 25 years ago was treated for refractory heart failure but died of right heart failure. At autopsy, primary pulmonary artery sarcoma was found in the right ventricular outflow tract, main pulmonary trunk, and bilateral pulmonary artery, and had invaded the aortic arch. The pathohistologic diagnosis was osteosarcoma. Echocardiography, chest computed tomography and right ventriculography performed 1 year before death did not reveal the presence of a tumor in the pulmonary artery. The history of this patient shows that primary pulmonary artery sarcoma grows rapidly, with, in this case, the patient dying within 1 year of its appearance. (Jpn Circ J 1998; 62: 379 - 381)
