Osteosarcoma of the bladder: a case report

BACKGROUND: Osteosarcoma arising from the bladder is extremely rare, with only 38 cases reported to our knowledge. It is often detected owing to hematuria, and is treated by surgery (for example, total cystectomy), radiation therapy, and chemotherapy; however, the prognosis is extremely poor. CASE PRESENTATION: An 83-year-old Japanese man underwent cystoscopy for postoperative follow-up of urothelial carcinoma of the bladder, which revealed a 2-cm nodular tumor on the right wall. He had a history of abdominal aortic aneurysm and hypertension, and had been smoking 15 cigarettes per day for 45 years. Seven years previously, the patient underwent transurethral resection of bladder tumor for a 5-cm tumor on the right wall of the bladder. The histopathological diagnosis was urothelial carcinoma. No recurrence had been detected since then. Transurethral resection of bladder tumor was performed, and the histopathological diagnosis was cystosarcoma. Because of his advanced age, we decided that it would be difficult to perform total cystectomy. We therefore performed a second transurethral resection of bladder tumor and found no residual tumor. At 29 months after surgery, the patient remains alive without recurrence. CONCLUSION: Bladder osteosarcoma has a poor prognosis. However, our case was detected early, and treatment with transurethral resection of bladder tumor alone resulted in long-term survival without recurrence. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13256-022-03346-2.