Abdominal BCGitis with hepatosplenic and lymphatic involvement following intravesical therapy: a rare complication.

Disseminated Bacillus Calmette-Guérin (BCG) disease, known as BCGitis, is a rare but potentially severe systemic complication of intravesical BCG therapy, which is used in the treatment of non-muscle invasive bladder cancer (NMIBC). Hepatic involvement in the form of granulomatosis typically presents as an early complication (within days to weeks after therapy), manifesting with clinical and laboratory findings such as abdominal pain, fever, and a cholestatic pattern. Definitive diagnosis is established through microbiological isolation of BCG and the identification of epithelioid granulomas in target organs, which enables the initiation of specific antituberculous treatment. The diagnostic process is often challenging due to the difficulty of microbiological confirmation and the variable timing of associated complications, necessitating a multidisciplinary approach involving gastroenterologists, pathologists, and other specialists.