Pulmonary Artery Sarcoma: A Rare Enemy Behind the Mask of Pulmonary Embolism

Abstract Pulmonary artery sarcoma (PAS) is a very rare and highly aggressive malignancy arising from the intimal layer of the pulmonary arteries. It commonly presents with nonspecific symptoms, often mimicking pulmonary embolism (PE), leading to treatment delays that worsen outcomes. We report a case of PAS initially managed as presumed PE in a middle-aged man. A 47-year-old man presented with intermittent right-sided chest pain, dyspnea, and fatigue following treatment for presumed pneumonia. Initial evaluation, including chest computed tomography (CT) angiography, revealed a filling defect in the right pulmonary artery, and anticoagulation was initiated for suspected PE. Six months later, the patient returned with persistent symptoms; repeat CT imaging demonstrated an unchanged intraluminal defect, an enlarged right hilar lymph node, and a right adrenal mass. Mediastinal lymph node biopsy was nondiagnostic. CT-guided biopsy of the adrenal lesion confirmed high-grade undifferentiated sarcoma. Positron emission tomography–computed tomography (PET-CT) demonstrated intense fluorodeoxyglucose (FDG) uptake in the right pulmonary artery, right hilum, and adrenal gland, consistent with metastatic PAS. Given distant metastasis and inoperability, the patient received palliative chemotherapy. PAS frequently resembles thromboembolic disease. Lack of response to anticoagulation, persistent vascular filling defects, extraluminal extension, and FDG uptake on PET-CT are important clues favoring PAS. Histopathological confirmation remains essential for definitive diagnosis. Early recognition is critical, as delayed diagnosis is associated with significantly increased mortality. Management includes surgery, chemotherapy, and radiotherapy, though prognosis remains poor in advanced disease. Increased clinical awareness may facilitate earlier detection and improved management of this rare but lethal entity.