The challenging sonographic inguinal canal evaluation in neonates and children: an update of differential diagnoses.

Bulging of the inguinal region is a frequent complaint in the pediatric population and sonographic findings can be challenging for radiologists. In this review we update the sonographic findings of the most common disorders that affect the inguinal canal in neonates and children, with a focus on the processus vaginalis abnormalities such as congenital hydroceles, indirect inguinal hernias and cryptorchidism, illustrated with cases collected at a quaternary hospital during a 7-year period. We emphasize the importance of correctly classifying different types of congenital hydrocele and inguinal hernia to allow for early surgical intervention when necessary. We have systematically organized and illustrated all types of congenital hydrocele and inguinal hernias based on embryological, anatomical and pathophysiological findings to assist readers in the diagnosis of even complex cases of inguinal canal ultrasound evaluation in neonates and children. We also present rare diagnoses such as the abdominoscrotal hydrocele and the herniation of uterus and ovaries into the canal of Nuck.