Four cases of disseminated Mycobacterium bovis infection following intravesical BCG instillation for treatment of bladder carcinoma.

: Intravesical BCG (bacillus Calmette-Guerin) instillation is a first-line treatment for superficial transitional cell carcinoma of the bladder. A rare but severe complication of BCG immunotherapy is the development of disseminated BCG disease, which can result in miliary pneumonitis, granulomatous hepatitis, soft tissue infections, bone marrow involvement, and sepsis. Symptoms can present as early as a few hours or as late as several months following the BCG therapy. The key finding in disseminated BCG disease is the formation of caseating granulomas in distant organs; detection of BCG organisms from tissue samples can be difficult. Recommended treatment for disseminated BCG disease includes a combination of antituberculous medications (with the exception of pyrazinamide, to which BCG is typically resistant) and a tapering course of steroids. We present the cases of four patients who developed granulomatous infection consistent with disseminated disease after intravesical BCG treatment and provide a summary of current clinical management recommendations.