Pulmonary artery intimal sarcoma is an uncommon tumor with a poor prognosis. We report a case of a 75-year-old man with a pulmonary artery sarcoma, recurrent following surgical resection. To palliate symptoms of this recurrence, he underwent CyberKnife stereotactic radiosurgery with a clinical and radiographic response of his treated disease. No acute or sub-acute toxicity was seen until the patient's death due to metastatic disease 10 weeks following treatment. The feasibility and short-term safety of this technique are reviewed, with emphasis on the stereotactic planning considerations, such as mediastinal organ movement and radiation tolerance.