This is Chocco, he is a 14 year old labrador. One day his owner contacted me because Chocco had been becoming slower and slower, he had lost much of his hair and what was left had changed colour to a light brown. His nipples were enormous as were his testicles and he couldn't pee normally. Chocco's owner was very sad but thought that it might be time to look at putting him to sleep as he was obviously not enjoying life. He was obviously suffering from - old age. She was surprised to find out that all of these signs were probably the result of a benign testicular tumour which was putting out the female hormone - oestrogen. As we say to our clients mutiple times each day - old age isn't a disease. 

These two photos are of Chocco when he first arrived at the clinic. We was quite lethargic. You can see he has lost most of his hair and what is left has turned a yellow/tan colour. He was also quite down in the dumps. He just wanted to lie down all the time.

So after a few other health checks (one revealing that he had a prostate the size of a grapefruit when normally it would be the size of a walnut) we castrated Chocco.

This is Chocco about seven weeks after his castration. You can see he is growing a new coat and it is dark brown as it should be. His owner also reports that he is happier and weeing much better.

Interestingly this photo was taken a long time before we saw Chocco. You can see by the colour of his coat that he probably had this tumour long before it really started having serious effects on him.

Canine testicular tumours

Testicular tumors are considered one of the most common tumours in older intact (unneutered) male dogs. The overall incidence in dogs is not very high because of the large number of dogs that are castrated. However, in intact male dogs these tumors are considered fairly common. The tumors are usually fairly easy to recognize and diagnose. Treatment consists of  castration and is usually curative.

Which dogs are at risk to develop testicular tumors?

Testicular tumors are most common in intact (unneutered) older male dogs. However, they can occur in intact males of any age. There does not appear to be any breed predilection for this tumor. The current cause of testicular tumors is unknown. Dogs that have one or both testicles that are not descended are 13 times more likely to develop a tumor in the undescended testicle than dogs with normal testicles. Except for the increased risk of these tumors in cryptorchid dogs, no other risk factors are readily apparent.

Are there different types of testicular tumors?

There are three common types of testicular tumors: Sertoli cell tumors, seminomas, and interstitial cell tumors. While there are differences in the types of tumors, they are often treated similarly and are therefore commonly lumped together as testicular tumors.

What are the symptoms?

Sertoli cell tumors show symptoms of swelling of the testicular and scrotal area. If the dog is cryptorchid, the swelling will occur in the inguinal or abdominal area depending on the location of the testicle. Up to 50% of the Sertoli cell tumors will produce estrogen and the dog will suffer symptoms of hyperestrogenism. These include an enlarged prostate gland, enlarged mammary glands and nipples, symmetrical hair loss, anemia, and the tendency to attract other male dogs. Sertoli cell tumors may metastasize to the abdomen, lung, thymus, and brain, however, this occurs in less than 15% of the cases.

Seminomas will also appear as swellings of the testicle, scrotum, and inguinal or abdominal area. Seminomas produce estrogen or metastasize in less than 5% of the reported cases.

Interstitial cell tumors show very few symptoms and do not produce estrogen or metastasize. They are usually incidental findings and not considered to be much of a problem.

How are testicular tumors diagnosed?

Diagnosis is based on history, presentation, and pathological identification through a biopsy or microscopic examination of the removed tumor. Dogs suspected of a testicular tumor should also have abdominal and chest x-rays to check for metastasis as well as a chemistry panel and a blood count (CBC).

What is the treatment for testicular tumors?

Treatment usually consists of surgical castration. Because of the success of testicular removal and the low rate of metastasis, castration is often the only treatment needed. Some dogs have been treated successfully with chemotherapy and in dogs that have metastasis, chemotherapy is sometimes recommended.

What is the prognosis for dogs that develop testicular tumors?

The prognosis for dogs with treated testicular cancer is usually very good. The low rate of metastasis makes surgical castration very successful and curative in most dogs. Dogs that develop hyperestrogenism from Sertoli cell tumors will often have a regression of symptoms, once the tumor has been removed. In severe hyperestrogenism that results in anemia some animals may require transfusions and more aggressive treatment. The prognosis for testicular tumors that have metastasized is more guarded and the outcome varies widely depending on location, type, and treatment.

How can testicular tumors be prevented?