Unilateral suprainguinal ectopic scrotum: the role of the gubernaculum in the formation of an ectopic scrotum.

A rare case of ectopic scrotum is described together with a review of the literature and a discussion of the embryological role of the gubernaculum in the formation and location of normal and ectopic scrota. We identified 16 reported cases of a suprainguinal ectopic scrotum, 4 cases of a femoral ectopic scrotum, 26 cases of penoscrotal transposition, and 19 cases of a perineal (accessory) scrotum. Although the gubernaculum is a prerequisite for the ultimate location of both the testis and scrotum, its role is complicated by the subsequent differential growth of the labioscrotal folds in which the gubernaculum is stabilized. If this interaction is disturbed, the result may be a suprainguinal ectopia, penoscrotal transposition or a perineal scrotum. A femoral ectopic scrotum, unlike the above, is the result of an aberrant gubernacular stabilization. While the etiology of these malformations is likely to be multifactorial, the existence of an inbred strain of rats characterized by a high incidence of an ectopic scrotum suggests a genetic component to this anomaly.