Disseminated Mycobacterium bovis Infection after Intravesical BCG instillation therapy

Abstract

Intravesical Bacillus Calmette-Guérin (BCG) therapy is an effective adjuvant treatment for non-muscle-invasive bladder cancer but may rarely cause disseminated infection. A
75-year-old man with an aortic vascular graft and high-grade urothelial carcinoma developed persistent fever, altered mental status, weight loss, and elevated inflammatory markers following BCG therapy. PET/CT revealed pathological uptake in
the liver and aortic prosthesis. Liver biopsy demonstrated granulomatous hepatitis, with identification of Mycobacterium tuberculosis complex, subsequently supported by positive mycobacterial blood and urine cultures.
Although antimycobacterial therapy rapidly controlled the infection, delayed diagnosis was followed by progressive clinical and functional deterioration. This case highlights the importance of early recognition of disseminated BCG infection and its diagnostic challenge.