Urothelial Bladder Carcinoma Incidentally Coexisting with an Ileovesical Fistula Caused by Perforation of Meckel’s Diverticulum: A Case Report

Background and Clinical Significance: Enterovesical fistulas are uncommon and are most often caused by inflammatory conditions. Cases caused by Meckel’s diverticulum are exceptionally rare, with only a few cases reported in the literature. To our knowledge, no previous reports have described an ileovesical fistula due to Meckel’s diverticulum coexisting with urothelial carcinoma. Case Presentation: A 74-year-old man was evaluated after presenting with fever and diagnosed with an ileovesical fistula. Since cystoscopy findings could not completely exclude bladder cancer, transurethral resection of the bladder tumor (TUR-Bt) was performed 1 month after the infection subsided. Histopathological examination confirmed the diagnosis of bladder cancer. Partial small intestine resection was performed 1 week after TUR-Bt to treat the ileovesical fistula. Histopathological examination of the resected specimen revealed perforation due to Meckel’s diverticulitis. TUR-Bt was repeated 3 months after the initial surgery, and no residual tumor was detected. At 6 months postoperatively, no recurrence of bladder cancer or fistula was observed. Conclusions: This case highlights an extremely rare coexistence of ileovesical fistula due to Meckel’s diverticulum and urothelial carcinoma. Given the potential for malignancy in or around fistulous lesions, careful diagnostic evaluation and appropriate management are essential.