Unsuspected rectal adenocarcinoma causing a urinoma.

A middle-aged man with a history of Hodgkin's disease presented with loin pain and microscopic hematuria. Radiologic studies demonstrated a urinoma secondary to ureteric obstruction at the pelvic brim. Percutaneous nephrostomy was performed to decompress the collection and a ureteric stent inserted to maintain drainage. Laparotomy revealed an unsuspected rectal adenocarcinoma. A metastatic deposit compressing the ureter had produced the urinoma. Metastatic colorectal carcinoma is a rare cause of urinoma.