The incidence of pulmonary tumor embolism in patients with solid tumors is estimated to be between 3% and 26% yet is rarely diagnosed. In this case, a 74-year-old male with sarcomatoid variant of urothelial carcinoma and recently diagnosed left renal vein thrombus treated with low-molecular-weight-heparin, presented to the emergency department with acute syncope and dyspnea. He was found to have CT imaging of segmental and subsegmental arterial filling defects, a right atrial filling defect concerning for thrombus in transit and was diagnosed with pulmonary tumor embolism syndrome. The patient was treated with aspiration thrombectomy, with pathology demonstrating sarcomatoid urothelial carcinoma cells. He was initiated on a combination of gemcitabine plus carboplatin to decrease the tumor burden. While pulmonary tumor embolism syndrome is associated with a poor prognosis, prompt diagnosis and initiation of cancer-specific therapies can significantly improve survival.