Metastatic bladder tumor from prostate cancer causing a ball valve-like obstruction in urination

We report a rare case of prostate cancer that apparently metastasized to the bladder and formed a pedunculated mass that caused a ball valve-like obstruction in urination. A 57-year-old man with metastatic prostate cancer was referred to the emergency department for acute urinary retention. Cystoscopy and magnetic resonance imaging revealed a pedunculated mass measuring approximately 2 cm in size in the bladder neck that appeared to cause urinary obstruction in a ball valve-like manner. Transurethral resection of the bladder tumor was performed that resolved his symptom, and histopathological findings confirmed a diagnosis of poorly differentiated prostate adenocarcinoma.