Usually, while the kitten is still developing in its mother’s womb, the testicles begin to migrate from the abdomen to the scrotum through the inguinal canal. Typically this process is complete between ten days and two months of age, but always by six months of age. Although it is very rare in cats, in some instances this migration process either never begins or it is not completed. When this occurs, one or both testicles remains in the abdomen, becomes lodged in the inguinal canal, or becomes stuck just under the skin in the groin. Any cat that is found to have this condition should receive treatment immediately as the retained testicle or testicles can cause pain and put the cat at a higher risk for developing tumors. Make sure to have all kittens examined by your veterinarian as well as any adult cat that you suspect of having one or both testicles retained.

Retained testicle, which is also called cryptorchidism, meaning “hidden testicle,” is a rare condition in male cats that results in one or both testicles being retained perpetually in the abdomen rather than lowering into the scrotum, which usually occurs by two months of age and always before six months of age. Unilateral cryptorchidism, which is the retaining of one testicle, is much more common than bilateral cryptorchidism, the retaining of both. A cat with only one retained testicle still produces sperm, while a cat with both testicles retained is sterile. Cats with either one or both testicles retained still produce testosterone.

In a kitten, there is generally only one symptom of retained testicle.

When an unneutered adult cat appears to have no testicles in its scrotum, as though it has been neutered, yet still displays the following behaviors, the cat should be examined by a vet to determine if the cat has one or two retained testicles:

A cat of any age with one or both testicles retained must be treated immediately as a cat with this condition can experience the following two symptoms:

Retained testicle is congenital in nature. Some breeds of cats, because of their breeding, are more commonly diagnosed with retained testicle than other breeds. 

Most cases of retained testicle in cats are discovered when kittens are six months in age or younger. Some pet-owners may become concerned, but usually, it is a veterinarian that diagnoses the condition during a visit to the vet for vaccinations.

Your veterinarian may:

The preferred treatment for retained testicle in cats is the removal of both testicles, whether in the abdomen or the scrotum, while your cat is under general anesthesia. If there is a testicle in the scrotum, it will be removed in the common procedure for neutering a cat, which is an incision in the scrotum. The abdominal testicle or testicles are generally removed by laparoscopy, which is a minimally invasive surgery that requires as few as two small abdominal incisions. Using laparoscopic tools, the abdominal testicle is removed through one of these incisions. 

On very rare occasions, more invasive abdominal surgery may be needed if the testicle cannot be located through laparoscopy. 

It is technically possible to surgically place the retained testicle into the scrotum. This is not recommended, however, because veterinarians usually deem it best that cats with this genetic abnormality not be allowed to breed.

Prognosis is excellent for cats that have been treated for one or two retained testicles. Your cat will likely be sore for as much as a week after surgery. Recovery time will be significantly less after a laparoscopic surgery than after a more invasive surgery. Your vet may prescribe pain medications during this period as well as antibiotics to prevent infection. After kittens heal you will likely observe no difference in their behaviors from before the surgery. Once both testicles have been removed from an adult cat, aggression, spraying, and sexual behaviors should disappear. Although your veterinarian will request a follow up appointment in order to assess your cat’s progress in healing, over the long-term your cat will likely have no further need of veterinary care for this particular condition.