Issue Description Testicular tumors are considered one of the
most common tumors in older intact (unneutered) male dogs. Other Names Canine Testicular Cancer, Testicular Cancer, Testicular Neoplasms
Causes 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 (cryptorchid)
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
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 mestasize 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.
Diagnosis 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 chemical panel and a blood count.
Treatment 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.
Prognosis 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.