Appendiceal abscess masquerading as acute urinary retention in children.

Two boys with acute urinary retention were found to have a persistent pelvic mass after bladder decompression. Evaluation in each disclosed a large pelvic abscess secondary to a ruptured appendix. The diagnosis of appendicitis may be difficult and appendiceal abscess presenting with acute urinary retention in children has been reported previously in only 7 instances. History, physical examination, laboratory studies, and radiographic and ultrasonic evaluations should lead to the correct diagnosis, and surgical intervention restores normal voiding.