Multiple Arterial Aneurysms in a Patient with Spondylitis Following Intravesical Bacillus Calmette-Guérin Administration for Bladder Cancer: A Case Report

Mycobacterium bovis is one of the species belonging to the Mycobacterium tuberculosis complex; its attenuated form-Bacillus Calmette-Guérin (BCG)-is used as a live vaccine against tuberculosis. Besides its use as a vaccine, BCG is widely used for treating bladder cancer. However, complications related to its use can lead to disseminated infection with M. bovis, known as BCGosis. BCGosis has multiple manifestations, and its culture requires a long time and complex polymerase chain reaction (PCR), posing challenges to its diagnosis. Herein, we report a case of a 74-year-old man with bladder cancer in whom multiple new arterial aneurysms developed during spondylitis treatment following intravesical BCG administration. The patient presented with syncope and left neck swelling. His medical history included transurethral bladder tumor resection and intravesical BCG therapy for bladder cancer. Sixteen months before he visited our institution, he developed spondylitis (L5/S1), an epidural abscess (L5/S1), and an abscess on the right thigh. Biopsy cultures and PCR confirmed M. tuberculosis complex, leading to antituberculosis drug therapy. Upon admission, multiple aneurysms were identified, and drug therapy was continued. However, new multiple aneurysms developed with the rupture of the right femoral aneurysm, leading to surgical interventions and arterial biopsy. The biopsy showed no signs of mycobacterial infection. Other aneurysm etiologies were ruled out and M. bovis was confirmed by PCR in the specimen from the initial intervertebral disc biopsy; thus, a diagnosis of BCGosis was made. This case highlights the importance of a thorough follow-up to detect new complications, even during treatment.