Miliary Mycobacterium bovis induced by intravesical bacille Calmette-Guérin immunotherapy

Intravesical instillation of bacille Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis, is the treatment of choice for many patients with bladder cancer. In a small percentage, this therapy is associated with systemic side effects including pneumonitis. It is uncertain whether these systemic manifestations are due to dissemination of infection or due to hypersensitivity, an etiologic distinction that has important therapeutic implications. We report the first case in which miliary M. bovis was proven to be the responsible mechanism, by culture of M. bovis biovar BCG from a transbronchial lung biopsy and complete resolution on anti-tuberculous chemotherapy.