Primary pulmonary angiosarcomas (PPAs) are rare, and often, their diagnosis is delayed because of insidious clinical symptoms and imaging findings mimicking pulmonary thromboembolism (PE). A 33-year-old female patient presented with chest pain and progressive dyspnoea. Her initial diagnosis, based on clinical symptoms and CT pulmonary angiography (PA) findings, was PE. However, after treatment with anticoagulants, the patient failed to improve. A follow-up CTPA and further CT-guided biopsy results were compatible with angiosarcoma.