Cryptorchidism is the failure of one or both testes to descend into the scrotum. The retained testicle/s may be located subcutaneously, in the inguinal canal or in the abdomen. It is also possible to have absence of testicle/s (monorchism and anorchidism). If the retained testicle is in the abdomen, it will not contain sperm since the higher core body temperature suppresses sperm development. However, retained testicles still produce testosterone.
The picture shows the difference in testicular size for a normal and cryptorchid patient. As you can see, the abnormal testicles are usually smaller. The retained testes have a higher chance of testicular tumor therefore it’s recommended to surgically remove them.