A 37-year-old man presented with months of weight loss, dysphagia and fatigue. He was an infrequent smoker, had no medical history and did not take regular medications. Endoscopy revealed gastro-oesophageal reflux only. Two months later, he presented with persistent cough and chest-X-ray (figure 1) revealed a large right-sided opacity.

Radiological appearances of the massive thymoma, showing plain chest X-ray, coronal CT and sagittal CT images.

Subsequent CT scan (figure 1) revealed a 165×122×128 mm mass in the right hemithorax, appearing to arise from the pleura, with compressive atelectasis of the lung. The diaphragm was intact, but the mass compressed the right atrium and superior vena cava (SVC).

He subsequently developed chest pains—blood tests were unremarkable, with no pulmonary embolus (PE) on CT …