Cryptorchidism is a condition in male cats where one or both testicles fail to descend into the scrotum. The term cryptorchidism comes from the Greek words kryptos, meaning “hidden,” and orchis, meaning “testicle.”
Normally, the testes develop near the kidneys within the abdomen and descend into the scrotum by two months of age. In some cats, this may occur later but rarely after six months of age. If the testicles cannot be felt in the scrotum after two to four months of age, cryptorchidism may be suspected.
In most cases, the undescended testicle is retained in the abdomen or in the inguinal canal, which is the passage through the abdominal wall into the genital region. Sometimes, the testicle may be located just under the skin in the groin region between the inguinal canal and the scrotum.
If the testicle is retained in the abdomen, it cannot be felt from the outside. An abdominal ultrasound or radiographs may be used to determine its exact location but this is not often done before surgery. Typically, only one testicle is retained, known as unilateral cryptorchidism. If a cat does not appear to have testicles but exhibits male behaviors, a hormonal test called an hCG stimulation test can be done to see if he has already been neutered. Alternatively, a veterinarian can check for penile spines which disappear six weeks after neutering.
Cryptorchidism affects less than 2% of cats and may be more common in purebred or pedigreed cats such as Persians, Himalayans, and Ragdolls. It appears to be inherited but its exact cause is not fully understood.
The most common signs of cryptorchidism are male marking behavior (spraying), male cat-associated odors, and aggression. Cats have fewer incidences of testicular cancer and complications associated with cryptorchidism than dogs. One complication is spermatic cord torsion (twisting onto itself) which can cause sudden and severe abdominal pain.
The treatment for cryptorchidism is castration of both testes even if only one has not descended. Surgery involves making an incision into the abdomen or inguinal canal to locate and remove the retained testis.
In summary, cryptorchidism is a condition where one or both testicles fail to descend into the scrotum. It can be diagnosed through physical examination or imaging techniques such as ultrasound or radiographs. The exact cause of cryptorchidism is not fully understood but it appears to be inherited. Treatment involves castration of both testes.