Bone marrow infection with bacillus Calmette-Guérin (BCG) after intravesical immunotherapy

Instillation of bacillus Calmette-Guérin (BCG) into the urine bladder is an effective treatment of superficial bladder cancer. BCG-mediated anti-tumor activity appears to be a local phenomenon in which cell-mediated immunity, involving cytotoxic T cells, lymphokine-activated killer cells and natural killer cells, is important for the elimination of malignant cells. Serious side-effects of BCG therapy are rare; nevertheless, BCG is a live, attenuated strain of Mycobacterium (M.) bovis and may exhibit invasive properties. Both local and distant or generalized infections have been reported after treatment with BCG. We describe the case of a 68-year-old man who developed bone marrow infection with BCG two years after intravesical instillation of BCG for treatment of superficial bladder cancer. He presented with intermittent fever, weight loss and pronounced pancytopenia. A bone marrow biopsy specimen showed granulomatous inflammation and BCG was cultured from the urine. Anti-mycobacterial treatment with isoniazid, rifampicin and ethambutol (pyrazinamide is inactive against M. bovis) led to full clinical recovery of the patient.