A 55-year-old male was admitted with coughing blood for 4 days. He had a history of smoking for 25 years and a previous episode of coughing blood 3 months ago. Investigations revealed an aneurysm of the descending aorta measuring 5.3 cm in size that was leaking into the left lung and pleural cavity, causing the patient's symptoms. Thoracic aortic aneurysms are most commonly due to atherosclerosis and can cause symptoms through compression of nearby structures or rupture. Surgical repair is indicated for symptomatic or rapidly enlarging aneurysms over 5.5-6 cm in diameter.
