Testicular Tumors in Dogs
In-depth Information on Diagnosis Complete physical examination. All intact male dogs should have their testicles palpated as part of their routine physical exam. Most testicular tumors are found incidentally during the exam, since most dogs do not display any symptoms of illness. The complete blood count evaluates the red and white blood cells. Low red blood cell counts indicate anemia, and elevations in the white blood cell count may indicate infection. The test is especially useful when an estrogen secreting tumor is suspected. Low red cell and white cell counts (leukopenia) would indicate a serious condition. The reticulocytes, which are young, recently released red cells from the bone marrow, might be counted, to determine whether the bone marrow was responding to the anemia by producing new red cells. The reticulocyte count would be low (non-regenerative) if the anemia was due to estrogen toxicity. Just as the red and white cell lines are decreased with bone marrow hypoplasia, the platelets also produced in the bone marrow may also be decreased. This test is especially important to run if any excessive bleeding or bruising is noted. The biochemical profile evaluates for liver or kidney disease, diabetes, and changes in electrolytes. Since most dogs are older if they have a Sertoli cell tumor, it is a valuable screening test for other concurrent diseases. If the tumor is malignant, and has metastasized (spread), elevations in liver enzymes might be noted. Additionally, all animals that are to undergo a surgical procedure should have a biochemical profile done as part of their preoperative blood work. If the testicular swelling is caused by an infection, a urinalysis (with a culture and sensitivity) might show bacteria and an increased white blood cell count. A urinalysis is also needed to fully assess kidney function. Even though metastatic disease is uncommon with most testicular tumors, thoracic radiographs are useful in evaluating the lungs for any potential tumor spread. In older animals, it is also a good preoperative screening test to evaluate for evidence of heart disease or other lung conditions. In the cryptorchid dog, abdominal radiographs are taken, as many larger testicular tumors may be easily visualized. Abdominal x-rays are also useful in evaluating the size and shape of other abdominal organs. Occasionally, with metastatic disease, the sublumbar (under the lumbar vertebrae) lymph nodes may be enlarged, and visible radiographically. An abdominal ultrasound is useful to better identify a mass within the abdomen as can be seen with a cryptorchid testicular tumor. The rest of the abdomen can also be checked for signs of tumor spread and other organ involvement. In non-cryptorchid dogs, generalized scrotal swelling is sometimes present. This may prevent accurate identification of a specific mass. A scrotal ultrasound is an excellent test to determine if a tumor is present in a swollen scrotum. With the aid of ultrasound, an abdominal mass can be aspirated by fine needle. The collected cells are then examined microscopically (cytology). A fine needle aspirate is generally a safe and effective method of tissue evaluation, but may not be diagnostic, since only a small amount of cells are collected. Intra-scrotal testicular masses generally do not require ultrasound for aspiration. A biopsy provides a better sample as a core of tissue is obtained for histopathology or microscopic examination of tissue. Biopsy usually provides more accurate information since a larger amount of tissue (usually the entire testicle) can be evaluated. Cryptorchid testicles are biopsied using ultrasound as a guide or at surgery. Many times the biopsy is combined with the full removal of the entire tumor (excisional biopsy). Based on the previous diagnostics, it is not always needed to biopsy a tumor prior to its removal.
In-depth Information on Treatment
Most dogs with testicular tumors have no symptoms and feel fine. Often the tumors are found incidentally on a routine physical examination. When found, the recommendation should be castration, unless the dog is a poor anesthetic risk, and the diagnostic evaluation suggests a benign condition.
Based on these findings, it may be more prudent to postpone surgery and observe the tumor for changes. This decision must be carefully discussed with your veterinarian, and the potential problems from not removing the tumor weighed carefully against anesthetic and other risks. If possible the tumor should be removed.
Cryptorchid testicles with tumors have a higher incidence of malignancy, and it is strongly recommended to have them removed. Cryptorchid testicles that are located under skin in the inguinal region are fairly easily removed, however, for cryptorchid tumors located within the abdominal cavity an abdominal exploratory is needed. Orchiectomy (castration). The treatment of choice for any testicular tumor is the surgical removal of both testes. Since the majority of testicular tumors are benign, the surgery is usually curative. Both testes are removed due to the high incidence of tumors involving both testicles. When removing abdominal cryptorchid tumors a complete evaluation of all internal organs should be done to check for evidence of metastatic disease. Chemotherapy is a treatment option for Sertoli cell tumors that have spread. Some of the drugs that have been used in treatment include: cisplatin, cyclophosphamide, vinblastine and methotrexate. Unfortunately, the prognosis of metastatic Sertoli cell tumor is grave regardless of therapy. Chemotherapy may decrease the tumor volume, and improve an animal’s quality of life for a few months but it is not a cure. Radiation therapy for metastatic seminomas is an option that may be available at certain referral institutions. Although metastatic seminomas are extremely rare, the tumors are relatively responsive to radiation therapy. Dogs that have bone marrow hypoplasia may be quite ill and require significant care. Therapy for anemia, infection, and potential bleeding problems needs to be addressed. Intravenous fluids, broad-spectrum antibiotics, and blood or platelet transfusions may be needed to stabilize the patient prior to the surgical removal of the tumor.
Bone marrow stimulating factors may also be used in an attempt to speed the recovery of the bone marrow cells, although its efficacy is uncertain. Specifically, erythropoietin is used to stimulate the red blood cell lines and granulocyte colony-stimulating factor (G-CSF) may be used for the white blood cell lines. Multiple blood transfusions may be needed to sustain an animal before the bone marrow recovers. Signs of bone marrow improvement may take three to six weeks, but not be normal for several months. Unfortunately, most animals with bone marrow involvement do not respond to therapy.