Retained Testicle (Cryptorchidism) in Cats

By Krista Williams, BSc, DVM, CCRP; Ryan Llera, BSc, DVM; Robin Downing, DVM, CVPP, DAAPM; Ernest Ward, DVM


What is cryptorchidism?

Cryptorchidism refers to the failure of one or both testicles (testes) to descend into the scrotum. Cryptorchidism is much less common in cats than in dogs. The testes develop near the kidneys within the abdomen and normally descend into the scrotum by two months of age. This may occur later in some cats, 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.

If the testicles aren't in the scrotum, where are they?

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 may be located in the subcutaneous tissues (just under the skin) in the groin region, between the inguinal canal and the scrotum.

How is cryptorchidism diagnosed?

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 cat that does not appear to have testicles but is exhibiting male behaviors, a hormonal test called an hCG stimulation test could be done to see if he is already neutered. Even simpler, your veterinarian can check for penile spines which are dependent on testosterone and will disappear six weeks after neutering.

What causes cryptorchidism and how common is it?

Cryptorchidism affects less than 2% of cats but may occur more often in purebred or pedigreed cats such as Persians, Himalayans, and Ragdolls. The condition is commonly seen in families of cats and appears to be inherited, although the exact cause is not fully understood.

What are the signs of cryptorchidism?

The most common signs of cryptorchidism are male marking behavior (spraying), male cat-associated odors, and aggression. Cats appear to have fewer incidences of testicular cancer and complications associated with cryptorchidism than dogs. 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. This condition, however, is rarely associated with pain or other symptoms unless a complication develops.

"If both testicles are retained, the cat may be infertile."

In the early stages, a single retained testicle is significantly smaller than the other, normal testicle. If both testicles are retained, the cat may be infertile. This is because retained testicles continue to produce testosterone but do not produce sperm.

There is also a risk that a retained testicle will become cancerous. The clinical signs associated with testicular cancer depend upon the specific type of cancer.

What is the treatment for cryptorchidism?

Neutering and removal of the retained testicle(s) are recommended. If only one testicle is retained, the cat 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.

What if I don't want to neuter my cat?

There are several good reasons for neutering a cat with cryptorchidism. The first reason is to remove the genetic defect from the breed line. Cryptorchid cats should never be bred. Second, cats with a retained testicle will continue to exhibit male behaviors such as marking and spraying, odors, and aggression toward other cats. Finally, the retained testicle may develop a cancerous tumor.

What is the prognosis for a cat with cryptorchidism?

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

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