Osteosarcoma of the urinary bladder occurring simultaneously with prostateand bowel carcinomas - Report of a case and review of the literature

Osteosarcoma is a very rare tumor of the urinary bladder, with only 28 well -documented cases reported in the literature to date. The tumors have chara cteristically been large and polypoid and most commonly have been located i n the trigone. An abdominal mass has occasionally been palpated, and rectal examination has frequently revealed a mass in the region of the bladder. T he prognosis for this tumor is very poor. In this report, a 75-year-old man with hematuria was found to have a primary osteosarcoma of the urinary bla dder with superficial invasion. Radical cystoprostatectomy and ileal condui t urinary diversion were performed. During surgery, a synchronous mucinous adenocarcinoma of the ascending colon was found, and a right hemicolectomy was performed. Prostatic adenocarcinoma was discovered from the histology. The patient died 7 months after surgery with systemic spread of the osteosa rcoma. Osteosarcoma of the bladder should be distinguished from other bladd er tumors that may be associated with bone formation, such as carcinosarcom as and transitional cell carcinomas with osseous metaplasia of their stroma , both of which have a better prognosis than osteosarcoma.