Pulmonary embolism with pulmonary hypertension or something far worse? Unveiling a rare and lethal pulmonary artery angiosarcoma: a case report.

Background: Pulmonary artery angiosarcoma is a rare and highly malignant tumour. Its clinical presentation often mimics common pulmonary disorders such as pulmonary embolism or pneumonia, which frequently leads to misdiagnosis. Due to its aggressive nature and typical diagnostic delay, prognosis is generally poor, with survival often limited to a few months post-diagnosis. Case Summary: A 70-year-old female with a history of hypertension and no previous cardiac issues presented with progressive exertional dyspnoea unresponsive to anticoagulation after a diagnosis of pulmonary embolism. A chest computed tomography (CT) initially suggested a pulmonary embolism with an endoluminal filling defect in the right pulmonary artery. However, further investigation revealed a mass in the right pulmonary artery with a subsequent obliteration of the perihilar fat spaces, leading to a diagnosis of pulmonary artery angiosarcoma. Discussion: This case underscores the importance of considering pulmonary artery angiosarcoma in differential diagnoses for persistent pulmonary symptoms, especially when imaging and clinical signs are atypical for thromboembolic disease. Early recognition and a multidisciplinary approach are essential for improving outcomes in this rare but lethal malignancy, where prompt diagnosis may extend survival significantly.