On reviewing the CT angiography of the chest, the top two diagnoses were pulmonary artery sarcoma and massive pulmonary embolism. However, the expansile nature of the filling defect on the chest CT angiography and the failed attempt of using recombinant tissue plasminogen activator strongly pointed toward the diagnosis of a pulmonary artery sarcoma. The patient underwent a left thoracotomy and pulmonary endarterectomy. A large tumor was excised from the artery lumen (Fig 3
, top, a), which was histologically a leiomyosarcoma (Fig 3, bottom, b). The patient quickly recovered from the operation. Subsequently, she received radiation therapy (5,040 cGy in 28 fractions) with two cycles of mitomycin C (8 mg/m2), doxorubicin (40 mg/m2), and cisplatin (60 mg/m2). In addition, she has received three cycles of adjuvant chemotherapy (ifosfamide [3,750 mg/m2] and doxorubicin [30 mg/m2]). She has recovered well. There are no signs of recurrence of the disease 9 months after the initial diagnosis.