A 69-year-old woman presenting with dyspnea had a pericardial window created for fibrinous pericarditis. The patient subsequently developed pulmonary hypertension and a ventilation perfusion scan was compatible with pulmonary thromboembolism. A primary tumour of the pulmonary artery was suggested by angiography, computerized axial tomography and magnetic resonance imaging. Pathology confirmed a spindle cell pulmonary artery sarcoma.