Leiomyosarcoma of the pulmonary vasculature is an extremely rare condition that has not been previously diagnosed by endobronchial ultrasound (EBUS) bronchoscopy. We present the case of a 43-year-old white male with a history of leiomyosarcoma who was diagnosed with pulmonary embolism 2 years ago. As the filling defects on follow-up chest computed tomography continued to worsen despite anticoagulation, EBUS-guided transbronchial needle aspiration (EBUS-TBNA) of the right pulmonary artery lesion was safely and successfully performed. Cytopathological examination revealed the “thrombus” to be metastatic leiomyosarcoma. In experienced hands, and carefully selected cases, EBUS-TBNA seems to be a safe and effective in diagnosing thoracic endovascular lesions.