Multiple mycotic aneurysms due to Mycobacterium bovis after intravesical bacillus Calmette-Guérin therapy

Mycotic aneurysms are exceptional complications after intravesical instillations of bacillus Calmette-Guérin (BCG) for bladder carcinoma. We report a patient who underwent an emergency operation for a ruptured carotid aneurysm 16 months after BCG therapy. Postoperative investigations discovered multiple other synchronous aneurysms. Culture of an abscess surrounding the right carotid artery identified Mycobacterium bovis var BCG. The patient improved clinically with antituberculous agents prescribed for 9 months but died from recurrence of bladder carcinoma 16 months later. A mycotic origin should be evoked when an aneurysm is discovered after BCG therapy. Microbiologic investigation of the artery wall is diagnostic.