Suspected Urine-Induced Chemical Peritonitis Secondary to Invasive Bladder Cancer: A Case Report.

Chemical (urine-induced) peritonitis is a rare but potentially life-threatening complication in patients with advanced bladder cancer. It may result from sterile urinary leakage into the peritoneal cavity, typically through microscopic wall disruption or tumor necrosis. This condition can mimic perforation or bacterial peritonitis, posing a significant diagnostic challenge. We describe the case of a 78-year-old male with de novo high-grade urothelial carcinoma, presenting with persistent gross hematuria, bilateral hydronephrosis, and severe anemia. Despite initial tumor resection and nephrostomy placement, the patient's condition deteriorated with signs of peritoneal irritation and systemic inflammation. Emergency cystoprostatectomy revealed extensive tumor necrosis and inflammatory peritoneal fluid, but no macroscopic bladder perforation. Histopathology confirmed muscle-invasive high-grade urothelial carcinoma (pT2b) with necrosis and angioinvasion. This report illustrates a diagnostic and therapeutic challenge in the management of advanced bladder cancer complicated by suspected sterile chemical peritonitis, emphasizing the importance of early source control in critically ill patients.