[Right upper lobar mass of the lung caused by subclavian artery aneurysm]

Subclavian artery aneurysm is a rare condition. The main causes are degenerative disease and, less often, trauma. We report the case of a sawmill worker with a large mass in the upper right lobe found in a routine X-ray. Imaging studies revealed the aneurysm to be 12.2 x 13.1 cm, partially thrombosed and located in the right subclavian artery. Our experience suggests that this cause of lung mass should be considered early in the diagnostic process, before undertaking invasive diagnostic (puncture-biopsy) or therapeutic procedures that might place the patient at risk.