Tumors of the Testicles

Condition Overview

Testicular tumors are common among male dogs. The 3 common testicular tumors in dogs are Sertoli cell tumors, interstitial (Leydig) cell tumor, and seminomas. A small percentage of Sertoli cell tumors and seminomas are malignant.

Symptoms

A swelling or firm mass in the inguinal canal in a dog with an un-descended testicle is characteristic of a testicular tumor (although the mass may simply be the un-descended testicle.

Tumors in descended testicles are less common. The affected testicle is often larger and firmer that its neighbor and has an irregular, nodular surface. At times the testicle is normal size but feels hard.

Some Sertoli cell tumors produce estrogen, which can result in feminization of the male with enlargement of the mammary glands, a pendulous foreskin, and bilateral symmetric hair loss. A serious complication of high estrogen levels is bone marrow suppression.

All symptoms +

Causes

Most affected dogs are over 6 years of age, with a median age of 10. The majority of tumors occur in un-descended testicles - located in the inguinal canal or abdominal cavity. In fact, tumors develop in up to 50% of un-descended testicles.

Diagnosis

Ultrasonography is particularly useful in locating un-descended testicles and determining whether a scrotal mass is a tumor, abscess, testicular torsion, or scrotal hernia. Fine needle biopsy provides information on the cell type of the tumor.

Treatment

Neutering is the treatment of choice. This is curative in nearly all cases, even when the tumor is malignant. For scrotal tumors in fully descended testicles, the normal testicle can be retained if future fertility is desired. Signs of feminization in Sertoli cell tumors may disappear after neutering - but this is not always the case.

Prevention

Tumors of the testicles can be prevented by neutering dogs early in life. It is particularly important to neuter all dogs with undescended testicles.

If one or both testicles are un-descended, both testicles should be removed, since the condition is inheritable and the dog should not be bred.

Support

Please contact your veterinarian if you have questions regarding this condition.