Failure of Migration and Descent of the Testis

One cause of cryptorchidism [Greek: hidden - gonad]

Incidence: Because the testis descends into the scrotum during the last month of pregnancy, many premature boys are delivered before the descent process is completed. Cryptorchidism occurs in about 3% of full term boys and 30% of boys born at 30 weeks of gestational age. Most undescended testes will spontaneously descend within the first six months of life.

Diagnosis: The boy should be relaxed and in a warm room. Cold examining hands will make the cremaster muscle contract pulling the testis into the inguinal canal. Start palpation along the inguinal canal, moving from a point just above the internal ring toward the scrotum. Try to entrap the testis between the hand moving along the inguinal canal and a finger placed on the scrotum. If the testis is not palpable or if it cannot be brought into the scrotum, cryptorchidism is present. Non-invasive imaging studies have been investigated to document the presence of a non-palpable testis (ultrasound, CAT scan, MRI scan, etc.), but none of these have proven sufficiently accurate to be useful.

Treatment: Through an inguinal incision, the patent processus vaginalis is opened. The testis usually lies inside the patent processus vaginalis. It is surgically freed from the surrounding attachments and the processus vaginalis is closed. At tunnel is made into the scrotum and the testis is brought through the tunnel and anchored in the scrotum. This is usually outpatient surgery.

Return to Normal Testis Development

Return to G/U Development home page.

©David A. Hatch, M.D., 1996