Retained Testicle (Cryptorchidism) in Cats
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.
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.
In cases of abdominal cryptorchidism, the testicle cannot be felt from the outside. Abdominal ultrasound or radiographs (x-rays) may be performed to determine the exact location of the retained testicle. Most cats have only one retained testicle, and this is called unilateral cryptorchidism.
What causes cryptorchidism, and how common is it?
The testes develop near the kidneys within the abdomen and normally descend into the scrotum by 2 months of age. This may occur later in some cats, but rarely after 6 months of age. Cryptorchidism may be presumed to be present if the testicles can’t be felt in the scrotum after 2 to 4 months of age.
"Cryptorchidism may be presumed to be present if the testicles can’t be felt in the scrotum after 2 to 4 months of age."
Cryptorchidism affects approximately 1.7% of all cats but occurs more often in purebred or pedigreed cats. Persians and Himalayans are the most likely to have this condition, with 10% to 29% of these breeds affected. 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 symptoms of cryptorchidism?
This condition is rarely associated with pain or other clinical signs (symptoms), until or unless a complication develops. 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 not sperm. The most common clinical 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.
"Cryptorchidism is rarely associated with pain or other symptoms, until or unless a complication develops."
Certain congenital abnormalities may occur with cryptorchidism. These include patellar luxation (dislocated kneecap), shortened or kinked tail, tetralogy of Fallot (a life-threatening heart defect), tarsal deformity (abnormal legs), microphthalmia (abnormally small eyes), and upper eyelid agenesis (eyelids that don’t develop).
What is the treatment for cryptorchidism?
Neutering and removal of the retained testicle(s) are recommended as soon as possible. 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 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.