We report the case of a 3-yr-old boy who presented an acute right hydrocele. A rapid scrotal swelling under tension developed the first hours and the child complained for discomfort especially during palpation of the scrotum. Three days later, surgical exploration revealed an incomplete torsion of a communicated and pedunculated peritoneal sac arising from the tunica vaginalis testis.The present case report represents the eleventh report of torsion of processus vaginalis saccular protrusion in the literature, being unique due to painless hematocele.