Disseminated Bacillus Calmette-Guérin (BCG) infection with pulmonary and renal involvement: A rare complication of BCG immunotherapy. A case report and narrative review.

Intravesical Bacillus Calmette-Guérin (BCG) instillation is a mainstay of adjunctive therapy for superficial bladder cancer that increases length of disease progression-free survival. Although usually well tolerated, moderate to severe local and systemic infectious complications can occur with this immunotherapy. Diagnosis is difficult and often based on high clinical suspicion since in many cases Mycobacterium bovis is not isolated. Treatment is not fully standardized but the combination of anti-tuberculosis drugs and corticosteroids is advocated in severe cases. The authors present an unusual case of a severe infectious complication following intravesical BCG instillation with pulmonary and kidney involvement. Prompt anti-tuberculosis treatment associated to corticosteroid resulted in a marked clinical and radiological improvement, supporting the diagnosis of disseminated BCG infection. Based on this, the authors aimed to review the literature on this exceptional complication of this immunotherapy.