Subclavian mycotic aneurysm presenting as mediastinal abscess

A 60-year-old man was admitted to a hospital for evaluation of intermittant fever, dysphagia, hoarseness, and general chest discomfort. Great vessel mycotic aneurysm was suspected when antibiotic trials failed and chest X-ray showed paraaortic mass with pleural effusion mimicking mediastinitis. Although the correct diagnosis of mycotic aneurysm of innominate artery was made thereafter and vigorous treatment was initiated immediately, this patient succumbed to overwhelming sepsis, probably due to a 2-week delay in another hospital. This case is reported to remind readers of the possibility of this unusual location of mycotic aneurysm. A high index of suspicion should be maintained to make an earlier diagnosis and obtain better prognosis. Computed tomography and 3D magnetic resonance angiography also significantly improve the diagnosis when mycotic aneurysm location is unusual and presentation is equivocal.