Bacille Calmette-Guérin (BCG) spondylitis with adjacent mycotic aortic aneurysm after intravesical BCG therapy: a case report and literature review

Although intravesical bacille Calmette-Guérin (BCG) therapy is accepted as an effective treatment for bladder cancer, serious complications may occur in rare cases. To date, only 4 cases have been reported in which the patient developed a combination of mycotic aortic aneurysm and BCG spondylitis. Accurate diagnosis of BCG spondylitis is important because it is an iatrogenic disease, and its treatment is different from usual tuberculous spondylitis. However, distinguishing BCG spondylitis from usual tuberculous spondylitis is very difficult and takes a long time. In this study, we were able to suspect BCG spondylitis at an early stage from the result of the interferon-gamma release assay (IGRA). We encountered a case of BCG spondylitis with adjacent mycotic aortic aneurysm after intravesical BCG therapy in a 76-year-old man. We performed a 2-stage operation to obtain spine stabilization and replace the aneurysm with a synthetic graft. We started multidrug therapy with antituberculosis medication, excluding pyrazinamide, because the patient's history of BCG therapy, negative IGRA, and positive of tuberculosis-polymerase chain reaction (Tb-PCR) suggested that the pathogenic bacteria of the spondylitis was BCG. Eventually the bacterial strain was identified as BCG by PCR-based genomic deletion analysis. BCG infection should be considered in patients who have been treated with BCG therapy, even if the treatment was performed several months to several years previously. In the case of a patient with a history of BCG therapy, a positive Tb-PCR result and negative IGRA result probably suggest BCG infections, if the possibility of false-negative IGRA result can be excluded.