Pulmonary artery intimal sarcoma(PAIS) is a rare tumor with a very poor prognosis. Clinical and radiological findings usually mimic thromboembolic disease, leading to diagnostic delays. The treatment of choice is surgery, and adjuvant chemotherapy and radiotherapy have limited results. We report the case of a 48-year-old male patient, initially suspected with pulmonary thromboembolism. The angio-CT revealed a filling defect in the pulmonary artery trunk. The patient underwent surgery, resulting in with complete resection of the mass with a diagnosis of PAIS. The tumor progressed rapidly in the lung, requiring surgery of multiple lung metastases. The patient was treated with stereotactic body radiation therapy(SBRT) on two occasions for new pulmonary lesions. In the last follow-up(4 years after initial diagnosis), the patient was disease-free. In conclusion, SBRT proved to be an alternative treatment to metastasectomy, allowing palliative chemotherapy to be delayed or omitted, which may result in improved quality of life. Pulmonary artery intimal sarcoma (PAIS) is a rare tumor with a very poor prognosis. Clinical and radiological findings usually mimic thromboembolic disease, leading to diagnostic delays. The treatment of choice is surgery, and adjuvant chemotherapy and radiotherapy have limited results. We report the case of a 48-year-old male patient, initially suspected with pulmonary thromboembolism. The angio-CT revealed a filling defect in the pulmonary artery trunk. The patient underwent surgery, resulting in with complete resection of the mass with a diagnosis of PAIS. The tumor progressed rapidly in the lung, requiring surgery of multiple lung metastases. The patient was treated with stereotactic body radiation therapy (SBRT) on two occasions for new pulmonary lesions. The last follow-up (4 years after initial diagnosis), the In conclusion, SBRT proved to be an alternative treatment to metastasectomy, allowing palliative chemotherapy to be delayed or omitted, which may result in improved quality of life.