Paediatric Imaging

Cryptorchidism

undescended testis. The testis develops in the abdomen and normally descends following the gunernaculum and processus vaginalis through the inguinal canal into the scrotum by the 8th month of gestation. Cryptorchidism is present in about 4% of term neonates. By one year the incidence of cryptorchidism is about 0.8% and is bilateral in 10%. The undescended testis may be located within the abdomen, anywhere from the renal hilum to the inguinal canal. Cryptorchidism is seen in a number of conditions in which there is a deficient production of gonadotrophin, e.g. pituitary hypoplasia or aplasia, or where there is a defect in androgen synthesis, or activation.

The undescended testis must be brought into the scrotum or removed as there is an increased risk of malignancy if left outwith the correct location. The role of imaging to identify an undescended testis is variable. Both ultrasound and MRI can identify the ectopic testis but in many centres imaging is not used, the testis being located at laparoscopy. Ultrasound is helpful in identifying ipsilateral renal agenesis, which if present means the testis is also absent. For a general description, see cryptorchidism.

HC