Testicular Tumors in Cats

Malignant testicular tumors are extremely rare, and most often occur in testicles that have not yet descended. While most testicular tumors in cats tend to be benign and won’t spread, it is important to seek immediate veterinary attention if you suspect your cat has testicular tumors.

Testicular tumors are usually small nodes within the scrotum that don’t cause a cat any pain. These tumors are very rare in cats; there are only a few reported cases. While the condition is more common in unaltered males, rare cases of testicular tumors in castrated cats have been reported. This type of tumor is usually located in the spermatic cord.

It is likely that your cat will not exhibit any signs or symptoms if affected by testicular tumors. However, if you notice any of the following symptoms in your cat, consult your vet immediately:

• Swollen or asymmetric testicles
• Loss of hair
• Changes in urination habits
• “Feminine” characteristics such as swelling of the nipples or mammary enlargement  (uncommon)
• Reddened skin due to hyperpigmentation
• Pale gums

If your cat seems to be in any pain, it is imperative that you take it to the vet right away.

The cause of testicular tumors in cats is not fully understood. Most instances of testicular tumors in cats are discovered during a routine examination or unusually aggressive male behavior. Any of the cells present in the testicles may become cancerous and form tumors. In some cases, cancer can be caused by exposure to radiation or hormones. 

One potential cause of testicular tumors is an underlying genetic disorder such as cryptorchidism, in which the testicles do not descend. An extremely rare cause may also be due to polyorchidism, or the presence of more than 2 testes. Older, unaltered cats have an increased chance of developing testicular tumors.

First, your vet will conduct a thorough physical examination for a tentative diagnosis. Be sure to inform your vet of the duration and extent of your cat’s symptoms as well as a complete medical history, particularly of any prior testicular disorders.

In order to reach a definitive diagnosis, your vet will usually perform a histopathology. This will involve taking a sample of the testicular tissue and examining it using a microscope. These samples will be submitted to a laboratory to be analyzed. 

Your vet may also use other tests to determine whether or not an infection is causing the enlargement of the testicles. These may include blood and urine analysis, blood count, fine needle aspiration, x-rays, and ultrasound of the scrotum.

Castration is the typical course of treatment for unaltered males diagnosed with testicular tumors. Complete castration – the removal of both testicles – was permanently curative for all 5 cats involved in one case study of testicular tumors in cats and dogs. Castration, though curative, is also an excellent preventative measure, particularly if the testicular tumors are malignant.

In the same aforementioned case study, metastasis – or the spread of tumors or cancer cells – was not reported in any of the cats following surgery. However, for all the cats involved, surgery resulted in the loss of secondary sex characteristics such as aggression and spraying behavior.

Your vet will typically recommend that you don’t feed your cat for 12 hours before the procedure. If your cat is older, your vet may have to determine whether or not it is safe for them to undergo anesthesia. However, complications from the castration procedure are rare.

The prognosis following castration is generally good to excellent. Your vet will recommend a recovery plan based on your cat’s specific needs. Always follow your vet’s instructions for postoperative care.

Following surgery, you’ll want to ensure your cat has a warm, secure place to rest. Don’t allow the cat to overexert itself and try to prevent running or jumping as much as you can. It is imperative that you do not allow your cat to irritate the surgery site, as this could cause complications and result in bacterial infection. An Elizabethan collar may help with this. It may be wise to keep your cat indoors until completely healed, even if the cat is used to going outside regularly. 

It is also important to check the surgery site regularly. If it starts to swell, bleed, or become infected, consult your vet immediately. Your vet may schedule a follow-up appointment to monitor your cat’s condition and to make sure the tumors have not recurred. If your cat required sutures that are not dissolvable, your vet will schedule a follow-up appointment to remove them.