A 72-year-old man presented with right-sided pleuritic chest pain, chronic cough and weight loss. Chest x ray revealed a moderate sized pleural effusion. Chest CT showed thromboembolism of the right main pulmonary artery, and pleural effusion with compression atelactasis of the right lower lobe of the lung (fig 1). As the thrombus appeared suspicious, being unilateral, central and occupying the entire lumen of the pulmonary artery without abnormality in the contralateral lung, magnetic resonance arteriography was performed which showed heterogeneous enhancement (fig 2). Positron …