MSRA-2731

A 70-year-old male, who migrated to the UK from India 8 years ago, presents to the respiratory clinic with a persistent cough and recent episodes of haemoptysis. The patient has never smoked and there are no notable findings on physical examination. A chest X-ray reveals a crescent of air partially outlining a cavitating mass in the right upper lobe. A CT scan of the chest is performed in both supine and prone positions, demonstrating movement of the mass within the cavity. The patient has not previously been screened for tuberculosis. What is the most probable cause of the mass?