Canine, Labrador Retriever, 12 years old, male, 73 pounds.
The dog presented for ear infection. Therapy has included ketoconazole and Otomax.
The findings include rectal temperature 101.2° F, heart rate 110/min, respiratory rate 20/min, pink mucous membranes, normal
capillary refill time, and normal heart and lung sounds. The physical examination showed BAR, asymmetrical testicles, tense
abdomen and ear infection.
Table 1: Results of laboratory tests
A complete blood count, serum chemistry profile and urinalysis were performed and are outlined in Table 1.
Thorough abdominal ultrasonography was performed with the dog positioned in dorsal recumbency.
The liver shows an inhomogeneous to homogeneous texture in its parenchyma. No masses noted within the liver parenchyma. The
gall bladder is mildly distended, and its walls are not thickened or hyperechoic. The gall bladder does contain some sludge
material. The spleen shows an inhomogeneous texture in its parenchyma - no masses noted. The left and right kidneys are similar
in size, shape and echotexture. Each kidney shows an inhomogeneous texture in the renal cortex. No masses or calculi were
noted in either kidney. The urinary bladder is distended with urine and contains some urine sediment material - no masses
or calculi noted.
The prostate gland shows a symmetrical shape and a mixed echogenicity in its parenchyma. The left testicle is enlarged and
some cavitations noted in the parenchyma. A mixed echogenic irregular-shaped mass-like structure is seen attached to the cranial
aspect of the left testicle. The right testicle is normal in shape and echotexture. The left and right adrenal glands are
similar in size and shape. The stomach, small intestine and pancreas are normal. The pancreas is prominent and shows a decreased
inhomogeneous texture in its parenchyma.
In this case, most likely neoplasia of the left testicle is present. There was no obvious evidence of cancer noted during
this abdominal ultrasound study. Castration is recommended and histopathologic examination done.
Review on testicular tumors
Testicular tumors are common tumors in older intact male dogs. The 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. Testicular tumors are most common in intact older
male dogs; however, they can occur in intact males of any age. There does not appear to be any breed predilection for these
tumors. 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 readily apparent.
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. Sertoli cell tumors show signs 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 percent of the Sertoli cell tumors will produce estrogen, and the dog will suffer signs 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 percent of the cases. Seminomas will also appear as swellings of the testicle, scrotum and inguinal or abdominal
Seminomas produce estrogen or metastasize in less than 5 percent of the cases. Interstitial cell tumors show very few signs
and do not produce estrogen or metastasize. They are usually incidental findings and not considered to be much of a problem.
Diagnosis is based on history, clinical 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 thoracic radiography to check for
metastasis as well as a serum chemistry profile and a CBC.
Treatment usually consists of surgical neutering. Because of the success of testicular removal and the low rate of metastasis,
neutering is often the only treatment needed. Some dogs have been treated successfully with chemotherapy and in dogs that
have metastasis chemotherapy is sometimes recommended.