Cryptorchidism is the medical term that refers to the failure of one or both testicles (testes) to descend into the scrotum. The testes develop near the kidneys within the abdomen and normally descend into the scrotum by two months of age. In certain dogs, it may occur later, but rarely after six months of age. Cryptorchidism may be presumed to be present if the testicles cannot be felt in the scrotum after two to four months of age.

In most cases of cryptorchidism, the testicle is retained in the abdomen or in the inguinal canal (the passage through the abdominal wall into the genital region through which a testicle normally descends). Sometimes, the testicle will be located in the subcutaneous tissues (just under the skin) in the groin region, between the inguinal canal and the scrotum.

In cases of abdominal cryptorchidism, the testicle cannot be felt from the outside. An abdominal ultrasound or radiographs (X-rays) may be performed to determine the exact location of the retained testicle, but this is not often done before surgery, as it is not required to proceed with surgery.

Typically, only one testicle is retained, and this is called unilateral cryptorchidism. If you have a dog that does not appear to have testicles, but is exhibiting male behaviours, a hormonal test called an hCG stimulation test can be performed to see if he is already neutered.

Cryptorchidism occurs in all breeds but toy breeds, including Toy Poodles, Pomeranians, and Yorkshire Terriers, may be at higher risk. Approximately 75% of cases of cryptorchidism involve only one retained testicle while the remaining 25% involve failure of both testicles to descend into the scrotum. The right testicle is more than twice as likely to be retained as the left testicle.

Cryptorchidism affects approximately 1-3% of all dogs. The condition appears to be inherited since it is commonly seen in families of dogs, although the exact cause is not fully understood.

One complication of cryptorchidism is spermatic cord torsion (twisting onto itself). If this occurs, there will be signs consistent with sudden and severe abdominal pain. More frequently, a retained testicle will become cancerous. The clinical signs associated with testicular cancer depend upon the specific type of cancer.

The treatment is neutering and removal of the retained testicle(s). If only one testicle is retained, the dog will have two incisions - one for extraction of each testicle. If both testicles are in the inguinal canal, there will also be two incisions. If both testicles are in the abdomen, a single abdominal incision will allow access to both.

There are several good reasons for neutering a dog with cryptorchidism. The first reason is to remove the genetic defect from the breed line. Cryptorchid dogs should never be bred. Second, dogs with a retained testicle are more likely to develop a testicular tumour (cancer) in the retained testicle. The risk of developing testicular cancer is estimated to be at least ten times greater in dogs with cryptorchidism than in normal dogs. Third, as described above, the testicle can twist, causing pain and requiring emergency surgery to correct. Finally, dogs with a retained testicle typically develop the undesirable characteristics associated with intact males like urine marking and aggression.

The prognosis is excellent for dogs that undergo surgery early before problems develop in the retained testicle. The surgery is relatively routine, and the outcomes are overwhelmingly positive.

If you are concerned about your male dog, please call us on 01665 252 250 to book in for a pre neutering check.