Testicular Tumors
There are three types of testicular tumors that occur with similar rate of incidence within the dog.
Sertoli cell tumor: Sertoli cells are located on the walls of the seminiferous tubules within the testicles and support the development of the spermatozoa. Tumors that originate from the Sertoli cells occur with less frequency in normal descended testicles, but have the highest incidence for occurrence in cryptorchid testes. These tumor cells have a high incidence for metastasis (spreading to other parts of the body). Sertoli tumors present as a firm nodule on the testis, and may reach significant size prior to diagnosis in an abdominal testis. Often males with Sertoli tumors present other systemic symptoms associated with hyperestrogenism (excess production of estrogen) which include anemia, hair loss, feminization, and attraction of other male dogs.
Seminomas: Seminomas arise from spermatogenic cells of the seminiferous tubules within the testicles. These tumors have a low incidence of metastasis (5-10% are metastatic). Seminomas usually are small and present as a soft mass within the testes. Some, however, particularly those that arise in abdominal testes, may become quite large. Like Sertoli tumors, seminomas may also secrete estrogen, however, they more commonly are associated with hyperandrogenism (excess production of androgen), which may lead to prostatic enlargement and/or development of perianal adenomas.
Interstitial cell tumors: Interstitial cell tumors originate from the Leydig cells of the testicle, which are testosterone-secreting cells. These tumors are usually benign and are found predominantly in descended testes and only rarely in abdominal testes. Interstitial cell tumors present as a soft mass within the testicles.
Diagnosis: Though ultrasound imaging is capable of detecting testicular tumors, only histopathologic examination will be able to differentiate between the three types of testicular tumors. Radiographs of the chest and abdomen are essential for conducting clinical staging of the cancer. When metastases occur, they typically are found in the lumbar lymph nodes, the spleen, and liver.
Treatment and Prognosis: Castration is frequently curative for testicular tumors, especially when performed in the early course of the disease. When staging indicates progressed disease as evidenced by distant sites of metastases, combination chemotherapy with vinblastine, cyclophosphamide and methotrexate has been observed to provide greater than 50% reduction in metastatic tumors. Seminoma metastases are also responsive to radiation therapy.
There are three types of testicular tumors that occur with similar rate of incidence within the dog.
Sertoli cell tumor: Sertoli cells are located on the walls of the seminiferous tubules within the testicles and support the development of the spermatozoa. Tumors that originate from the Sertoli cells occur with less frequency in normal descended testicles, but have the highest incidence for occurrence in cryptorchid testes. These tumor cells have a high incidence for metastasis (spreading to other parts of the body). Sertoli tumors present as a firm nodule on the testis, and may reach significant size prior to diagnosis in an abdominal testis. Often males with Sertoli tumors present other systemic symptoms associated with hyperestrogenism (excess production of estrogen) which include anemia, hair loss, feminization, and attraction of other male dogs.
Seminomas: Seminomas arise from spermatogenic cells of the seminiferous tubules within the testicles. These tumors have a low incidence of metastasis (5-10% are metastatic). Seminomas usually are small and present as a soft mass within the testes. Some, however, particularly those that arise in abdominal testes, may become quite large. Like Sertoli tumors, seminomas may also secrete estrogen, however, they more commonly are associated with hyperandrogenism (excess production of androgen), which may lead to prostatic enlargement and/or development of perianal adenomas.
Interstitial cell tumors: Interstitial cell tumors originate from the Leydig cells of the testicle, which are testosterone-secreting cells. These tumors are usually benign and are found predominantly in descended testes and only rarely in abdominal testes. Interstitial cell tumors present as a soft mass within the testicles.
Diagnosis: Though ultrasound imaging is capable of detecting testicular tumors, only histopathologic examination will be able to differentiate between the three types of testicular tumors. Radiographs of the chest and abdomen are essential for conducting clinical staging of the cancer. When metastases occur, they typically are found in the lumbar lymph nodes, the spleen, and liver.
Treatment and Prognosis: Castration is frequently curative for testicular tumors, especially when performed in the early course of the disease. When staging indicates progressed disease as evidenced by distant sites of metastases, combination chemotherapy with vinblastine, cyclophosphamide and methotrexate has been observed to provide greater than 50% reduction in metastatic tumors. Seminoma metastases are also responsive to radiation therapy.