Mycotic aneurysm of the aorta as a complication of Bacillus Calmette-Guérin instillation.

Bacillus Calmette-Guérin (BCG) is a live attenuated strain of Mycobacterium bovis that has been widely used for the treatment of superficial transitional cell carcinoma of the bladder. We describe a rare case of supra-renal mycotic aortic aneurysm secondary to BCG instillation in a 75-year-old male. Patients presenting with systemic symptoms post-instillation, possibly with an aneurysm, should raise suspicion of BCG dissemination, which requires early instigation of anti-mycobacterial drugs.