Granulomatous myocarditis arising from intravesical Bacillus Calmette–Guérin therapy leading to death diagnosed by postmortem examination: a case report

Background Intravesical Bacillus Calmette–Guérin (BCG) is used as a standard adjuvant therapy for non-muscle invasive urothelial cancer. Most patients tolerate the treatment well, with mild side effects. Systemic complications are extremely rare, occur due to BCG dissemination and are associated with immunocompromised state and urothelial breach. Case presentation We present a case of a 78-year-old male, a former smoker, with history of non-muscle invasive urothelial carcinoma status post partial resection followed by intravesical BCG therapy. An autopsy was performed due to the sudden nature of his death. Autopsy showed multiple necrotizing granulomas in the brain, atrium, ventricles, lungs, kidneys, and urinary bladder. Stains for acid-fast bacilli and fungi were negative. In addition, bilateral lungs showed evidence of bronchopneumonia secondary to cytomegalovirus. Conclusion Granulomatous myocarditis arising from BCG therapy is extremely rare. Our patient with urothelial cancer treated with BCG developed multiorgan granulomas, most likely due to a hypersensitivity reaction to intravesical BCG. Arrhythmia induced by granulomatous myocarditis was the cause of his death. Although there have been few cases of systemic BCG-osis causing fatal sepsis leading to death, a cardiac cause of death is unique.