Testicular Tumors of 54 Birds and Therapy in 6 Cases
Presenting Author: Drury Reavill, DVM, Dipl ABVP (Avian) and Scott Echols, DVM, Dipl ABVP (Avian)
Zoo/Exotic Pathology Service, West Sacramento, CA
Westgate Pet & Bird Hospital, Austin, TX
Interpretive Review and comments by Dr. Nemetz:
This year Dr. Reavill concluded her retrospective study into reproductive tumors of birds. Last year she wrote on the Ovary and Oviduct tumors (Click here). This year she discussed the "male" side of things. Testicular tumors of birds are best described in budgerigars ( Melopsittacus undulatus) and pigeons ( Columba livia). Reported tumors include seminoma, Sertoli cell tumor, interstitial cell tumor, lymphosarcoma, undifferentiated sarcoma, and teratoma. Seminoma and Sertoli cell tumor are the most common. At the BIRD Clinic diagnosis of testicular tumors correlate with this study but other species are represented similar to the ones to be described.
In a review of 11,163 companion bird samples submitted to her pathology service from July 1, 1998 to January 1, 2004 there were 54 cases of male reproductive tract tumors.
Twenty-four (44%) Sertoli cell tumors were identified. These are primary testicular tumors of gonadal-stroma that arise from the Sertoli (sustentacular) cells. Clinical signs included anorexia, dyspnea, and cardiac changes (murmurs, slow heart rates). Two budgerigars had a color change of their cere from blue to brown, as Sertoli cell tumors are capable of producing high levels of male hormone precursors (feminizing hormones). Two cockatiels of the seven submitted demonstrated metastasis to the liver. Average age at diagnosis was 10.2 years.
Twenty-one (39%) seminomas were identified. These are tumors of immature germ cells of the testis. Vague signs of lethargy, anorexia, and dyspnea (difficult breathing) were most commonly reported. Average age at diagnosis was 9.2 years.
Nine (17%) other tumors included interstitial cell tumors, lymphosarcoma, leiomyosarcoma, undifferentiated sarcoma, and an undifferentiated tumor.
Various treatment modalities have been tried including surgical removal, chemotherapy, radiation therapy, and hormonal therapy with mixed results dependent on species afflicted.
Surgical removal seems to be the best overall treatment in species over 200gms and recommended by Dr. Nemetz. This is a delicate surgery that requires good microsurgical equipment and skills. For species under 200gms, mainly budgerigars and cockatiels, radiation therapy by orthovoltage (Dr. B. Speer) or Strontium-90 (Dr. L. Nemetz current research) therapy has promise in the future.