Mycotic aneurysm of the left subclavian artery: CT findings.

Mycotic aneurysms caused by aspergillosis are rare. We report a nine-year-old girl with acute lymphoblastic leukaemia who had invasive pulmonary aspergillosis and subsequently developed a left subclavian artery aneurysm. Prior to the aneurysm, computed tomography (CT) of the chest showed a nodule with an air crescent in the left upper lobe, adhering to the mediastinum and the left subclavian artery. The left subclavian artery was ill-defined and had a small lumen, and it was embedded in the wall of the nodule. 37 days after the chest CT, the patient underwent a left thoracotomy because of massive haemoptysis, at which time a false aneurysm in the left subclavian artery was found. Plication of the aneurysm was performed. On a follow-up CT with multiplanar reconstruction six days after surgery, there were the plicated aneurysm and a small amount of pleural effusion in the upper portion of the left hemithorax, adjacent to the plication. In invasive pulmonary aspergillosis, it is important to be aware of the possibility of mycotic aneurysms, particularly in patients with pulmonary lesions adjacent to mediastinal vessels with ill-defined borders and small lumens, since the aneurysms may increase in size and rupture. CT, particularly multidetector CT, helps in visualisation of mycotic aneurysms.