Cryptorchidism (Retained Testicle)

What is it?

Testicles develop near the kidneys and normally move into the scrotum by about two months of age, rarely later than six months. In cryptorchidism, one (usually) or both stay in the abdomen, the groin canal, or under the skin of the groin. It affects less than 2% of cats, appears to be inherited, and may be more common in breeds such as Persians, Himalayans, and ragdolls.

What signs should I watch for?

It is rarely painful. You may notice only one testicle, or none, in the scrotum after two to four months of age. The most common signs are male behaviors such as urine spraying, aggression toward other cats, and a strong tomcat odor, which may be the clue in a cat with no visible testicles. A retained testicle can twist, causing pain and requiring emergency surgery.

How is it diagnosed and treated?

Your veterinarian may find the testicle by feeling the groin, or locate it with ultrasound or X-rays or at surgery. Checking for penile spines, which disappear about six weeks after neutering, or hormone tests can show whether testicles remain. The recommended treatment is neutering, removing both testicles.

Can it be prevented, and what's the outlook?

• The outlook is excellent when surgery is done early.
• A retained testicle may become cancerous, and affected cats should never be bred because the condition is inherited.