A 38-year-old nonsmoker spent six months getting steadily more breathless. A CT scan of his lungs showed saddle-shaped filling defects straddling both main pulmonary arteries, the classic radiologic sign of a large pulmonary embolism. He was started on anticoagulation for pulmonary embolism.
Three months later, on adequate blood thinners, he was worse. He had gone from mild limitation to breathlessness at rest. The scans had not cleared. When surgeons finally opened his chest expecting to scrape out an organized clot, they found a firm mass invading the artery wall.
