Peripelvic extravasation, urinoma formation and tumor obstruction of the ureter.

We report 4 cases of peripelvic extravasation caused by tumor obstruction of the ureter. A urinoma developed in 3 of the 4 cases. Review of the literature reveals only 5 previously reported cases of peripelvic extravasation secondary to tumor obstruction of the urinary tract. We discuss the mechanics of peripelvic extravasation and urinoma formation, and conclude that tumor obstruction of the ureter must be considered in all cases of peripelvic extravasation.