Angiosarcoma of Bladder
The patient was a 65 y/o female with a history of uterine malignancy treated by radiation in the 1950's. She presented with gross hematuria and was found on cystoscopy to have a reddish tumor in the bladder wall. The image shows variably-sized vascular channels lined by atypical endothelial cells under an uninvolved intact urothelium. Immunostaining with CD31 and CD34 was positive in the atypical cells confirming the diagnosis of angiosarcoma.