Torsion of a benign cyst arising from the tunica vaginalis testis.

We describe a rare case of torsion of a benign cyst originating from the parietal layer of tunica vaginalis. This case presented with acute scrotum. Surgical exploration revealed a cyst arising from the parietal layer of tunica vaginalis of which the pedicle was twisted. When a cystic mass is detected in the scrotum of boys with acute scrotum, torsion of a cyst in the cavum tunica vaginalis testis should be considered.