[Bilateral pulmonary artery occlusion due to primary pulmonary artery sarcoma; report of a case].

60-year-old female who complained of severe dyspnea was admitted with a diagnosis of massive pulmonary embolism. An emergency operation was undertaken due to right side heart failure. Under extracorporeal circulation with beating heart, large, white and smooth surface mass which was originated from right pulmonary artery was removed. Pathology of the mass showed low differentiated sarcoma. No evidence of other primary lesion by positron emission tomography-computed tomography (PET-CT) suggested primary pulmonary artery sarcoma. We scheduled total resection of the right lung, however postoperative CT showed large mass occupying from right pulmonary artery to main pulmonary trunk. Palliative chemo radiation therapy was introduced. Pulmonary artery sarcoma mimicking pulmonary thromboembolism is so malignant that the diagnosis and treatment should not be delayed.