Carcinosarcoma of urinary bladder mimicking vesical calculus: a case report.

We report a 50 year old male who presented with a short history of gross hematuria. An ultrasonogram detected a mass arising from the right lateral wall of the urinary bladder. Computed tomography of the abdomen revealed that the mass was a calcified lesion mimicking a bladder stone. Cystoscopy confirmed the presence of the calcified lesion and biopsy revealed a rare biphasic tumor of the urinary bladder comprising of osteosarcoma and a papillary urothelial neoplasm of low malignant potential. The rarity of this tumor and its associated exuberant calcification make this case an interesting one.