Malignant fibrous histiocytoma mimicking pulmonary embolism.

A rare case of malignant fibrous histiocytoma occurring in the pulmonary artery is reported. Such primary pulmonary artery sarcomas may have the diagnosis suggested by angiography or echocardiography; radiographically and in perfusion-ventilation scanning their usual unilateral origin (with later spread) and the persistence of the perfusion defect are among the features normally distinguishing them from thromboembolism.