Society of Uroradiology Award paper. The pars infravaginalis gubernaculi: importance in the identification of the undescended testis.

The gubernaculum, a cordlike structure that extends from the testis to the scrotum and guides the testis in its descent, has a bulbous termination, the pars infravaginalis gubernaculi. We reviewed seven surgically proved cases in which the pars infravaginalis gubernaculi was mistaken for an undescended testis on imaging studies. The studies included sonography (five cases), CT (two cases), and MR imaging (two cases). Identification of the mediastinum testis on sonograms or MR images confirms that a structure is testis and not the pars infravaginalis gubernaculi. In two of these patients, testicular venography was used to further identify the undescended testis. In these two patients, the pampiniform plexus, which is used to identify the presence and position of testis, was located adjacent to the pars infravaginalis gubernaculi. Our experience indicates that the pars infravaginalis gubernaculi can be similar in appearance to the undescended testis on any imaging study. The finding of an apparent cord leading to a testislike structure on caudad sectional imaging does not obviate searching for the testis as far as the renal hila.